# Why do some old school guys despise class D?



## PPI_GUY

I am a member of several FB-based old school car audio groups and the outright hatred for anything using class D topology is amazing! 
Now, I am as old school as they come. Started in car audio in 1987 and use old PPI class AB amps on a daily basis. But, I'm not so closed-minded to believe that time should stand still, that no progress has been made in mobile power supplies over those 28 years. 
You can even reference that several all-class D setups have won SQ competitions and that doesn't seem to matter either. 
I am not here to advocate for either class AB or D. Just wondering why all the hostility toward newer and ever improving technology?


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## turbo5upra

Because they haven't taken the time to a/b them...


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## thehatedguy

Because they are stuck in 1992 with Audio Control analog processors and like having 3 extra batteries in the trunk.


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## SkizeR

to add what the other guys said, they will say that stuff now "isnt made like it used to be", or american made stuff is better, or whatever. i actually think if you compare apples to apples now, the newer stuff is better. what ive noticed from the majority of them are just stuck clinging to the past back when their cars were worth talking about and have a crazy superiority complex where they automatically think your an idiot for using class d, or a dsp, or anything else from after the turn of the century


also, sub'd for the foreseeable ****storm approaching


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## Lycancatt

the first runs of many class d amplifiers weren't all that great, especially full range ones, and while those flaws have pretty much all been ironed out by now, many are jaded into thinking the class d is inferior. we have the same "tubes are the only way for best sound" in home audio and I'd never go back to my tube amps, my cats wish I did though, they were definitely warm lol.


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## gijoe

Until fairly recently, class D's switching frequency wasn't high enough to be used fullrange. Ten years ago class D sub amps were common, but not fullrange. Things have improved since then, the switching frequencies have gotten high enough that they can play fullrange without issues, but this wasn't the case not so long ago.


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## SkizeR

i dont even think it has to do with the actual topology of the amp that makes them not like it. its the era


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## hot9dog

I'm a stuck in the mud class A/B guy myself. For me it's based on nostalgia and for the finite high end details. But when it comes to the subwoofer stage, it's class D all the way!! I would love to run class A/B for the sub stage, but the electrical draw would be thru the roof and it take up a lot or real estate. 
My wife's car is class D , all channels, and it's super clean and efficient. I'm a nostalgic stick in the mud when it comes to my personal ride.


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## gijoe

SkizeR said:


> i dont even think it has to do with the actual topology of the amp that makes them not like it. its the era


Nostalgia certainly plays a role. It's the same reason why so many people love old cars even when most newer cars are superior in every objective way. We like things from our past, change is scary.


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## Brian_smith06

I'm too young to be an "old school" guy but I am a class a/b guy. All 3 amps in my car are a/b including the sub stage. Have I used class d before? Yep, when I first started out, jl 1000/1, followed by a pair of us amps xt2000d, and finally a powerbass asa1500d. I loved the 1000/1 and would run one again in a heartbeat. The other 2 not so much. They were turds. That being said also were made when class d was getting big so wouldn't be a fair comparison to todays class d amps. 

I have only heard one class d full range amp and was not impressed. That being said it was a low end DD amp with PA speakers on it so probably not the best setup to base an opinion on all of class d. I am open to auditioning some class d though if somebody in the area has anything I can listen to? I suppose I could also go down to a local audio shop. I know they sell JL HD amps and also push for people to buy upper end Hertz stuff. I may have a project for the weekend.


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## Lycancatt

this last post echos my approach as well. class a/b for everything I can, but with the levels of bass I want, its not remotely practical to use class a/b.

honestly I wish there were more class h car audio amplifiers like the qsc pro audio stuff I use and love.


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## SkizeR

only reason i dont use class d.. i cant find any that i like the look of except the arc xdi. then theres the cost and features. my ab amps i can get for cheap, and have built in dsp's. room and current draw werent really an issue so i had every reason to use ab


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## gijoe

Even if there was a sonic difference, it isn't worth it to me. I ran a Zuki Eleets 4 channel and a Xenon (class D) 600.1, and had to replace my alternator about once a year. To be fair, it was a re-manufactured autozone brand alternator that I just kept swapping out under warranty, but it was a hassle. With road noise, engine noise, reflections, etc. the strain on my electrical system wasn't worth any slight (and most likely inaudible) SQ improvement. I love my PDX amps, they are compact, make good power, no noise, super tidy wiring, and don't put much strain on my electrical system.


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## capea4

I'm just an old school guy cause it was the **** I grew up installing, and couldn't afford. I use some lab gruppen class d stuff in home audio, but the reliability hasn't been there.


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## 1996blackmax

Reminiscing about the good ole days. I get it, I was like that too. 

Out of curiosity, I wanted to try class d fullrange. I first tried the Soundstream Tarantula Nano amps earlier this year. I used a Boston GT-475, GT-2125, & GT-2200 before that. I felt that the TN's were good bang for the buck amps. I'm on board with fullrange class d now. I went with Rockford recently because I like their power series amps.


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## Victor_inox

Take from an engineer who is as old schools as it gets, those guys full of ****, deaf or must sell their old equipment. There is absolutely no other reasons to stick to old school. IMHO of course. 
I design class D amps myself and have a few patents pending.
going to introduce Single ended D class amp very soon. final testing stages.
up to 800Khz switching frequency. 200W at 8Ohm- 97% efficiency. 

actually have few of them build for customers, reviews coming.

I also have class A amps as well and prefer my new D for power, transient response, no heat and complete lack of sonic signature.


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## hot9dog

For me it's also aesthetics, I'm not trying to win a race here. If I was in a competitive mindset as far as car audio goes, then I might think differently. I like the monolithic look of a big ass amp in my trunk, this hobby is an artistic extention of myself. .. how I envision it looking in my mind and then making revision changes to that vision to produce an acceptable soundstage. I choose the amps as a form of canvas. But then again... I'm kinda ****ed up in the head! Lololo


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## 1996blackmax

hot9dog said:


> For me it's also aesthetics, I'm not trying to win a race here. If I was in a competitive mindset as far as car audio goes, then I might think differently. I like the monolithic look of a big ass amp in my trunk, this hobby is an artistic extention of myself. .. how I envision it looking in my mind and then making revision changes to that vision to produce an acceptable soundstage. I choose the amps as a form of canvas. But then again... I'm kinda ****ed up in the head! Lololo


I was about to say the same thing....I still love the looks of some of those old school amps.


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## Victor_inox

And that is fine with me, 
Do you believe that majority of cars will be electric in foreseeable future?
I do believe that. then there will be no class AB inefficient amplifiers in them.
absolutely no reason to waste battery power on heat. 
Like it or not that is the future. 
Home audio started transition process with best D amplifiers sold as much as 25000 per stereo. sometimes even cheaper models 500-1000 sounds great. Switching frequency going up just like computer processors did and already reaching Ghz range.
Depending on use of input stages and output stage design D can sound absolutely transparent- have no sound signature on it`s own. 

Aesthetics of old schools is nostalgia nothing more, once it`s faded out it will be forgotten.


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## 1996blackmax

I also think some guys just think the old school amplifiers were just better....better built, better looking, better sounding...etc. If that's what they want to run, that's fine. I myself am happy with the power, efficiency, & sound of my class d amps.


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## High Resolution Audio

1996blackmax said:


> I also think some guys just think the old school amplifiers were just better....better built, better looking, better sounding...etc. If that's what they want to run, that's fine. I myself am happy with the power, efficiency, & sound of my class d amps.


They are for a fact better built, but as far as aesthetics, that is subjective, and as far as better sounding, that is subjective as well. But as long as we are both happy with our systems, that is all that matters.


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## edzyy

High Resolution Audio said:


> They are for a fact better built, but as far as aesthetics, that is subjective, and as far as better sounding, that is subjective as well. But as long as we are both happy with our systems, that is all that matters.


Built better my ass.


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## 1996blackmax

While I haven't run fullrange class d for long, I have used them for sub duty for many years. No problems with any of them at all....I think they were built pretty damn well.


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## PPI_GUY

Good comments and observations guys. That's what I was hoping for instead of a AB vs. D crap storm. I've used both AB and D amps and in a moving vehicle, with road noise I can't tell any difference. Maybe I don't know what to listen for? Maybe I don't have a critical ear like a SQ judge might have? 

But, honestly how many people compete in an environment where someone might notice? Most people...those you'll never see post here...just want a little extra bass in the hatch of their compact SUV. I'd think the number of people who buy a new (or near new) vehicle and want a full-bore system revamp is fairly small. Just look at the way brick & mortar stores are vanishing. 

However, I will say that higher end companies still seem to be all-in on class AB amplification. That has to say something too. Are those companies (some heavy hitting, well known names) the last gasp of what we've come to call old school?


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## 1996blackmax

I think so....things are changing as Victor mentioned.


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## BlackHHR

I may be stepping into the class D amps for my front stage. Seriously looking at the JL 600/4`s bi lateral for the front stage. I am going to give it a go. 
This will be the first time I have ever used a class d for anything.


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## hot9dog

I like class D amps. They are evolving and are starting to be a heavy hitter in the audio world. I'm all for innovation, at this rate of progression. ..I'm sure we will see an 8 channel amp the size of a shoe box in a few years. This industry has taken it on the chin for a long time, innovationso like this will help it out. I'm nothinking saying I will NEVER run a full class D system, just not right now.


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## WestCo

The ppi 900.4 is impressive for what it is and will smoke a lot of the old school stuff on clarity and balanced sound. Every audio component has a sonic signature. What makes a great amp is not it's class necessarily, but the quality of the internals and the engineering behind them.

It's been my findings that damn near everything out there benefits for aftermarket modifications. What irritates me is that corners are cut to save cost.


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## High Resolution Audio

edzyy said:


> Built better my ass.


Come see me in 20-25 years. See if your amp is still running. I guarantee it wont be. Your amp is built to a price point. Do you know and understand what that means? It's considered disposable. It's built so in-expensively, it's considered throw away. The cost to fix your amp when it blows will outweigh the cost of a new one.


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## Lycancatt

victor, link us please, because all I ever hear about class d is power supply sag, which is obviously a problem in class ab too, but I want to know why in class di is it apparently so much worse.


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## wheelieking71

I just back to back tested a class-D full range against a high-bias class-A/B amp about a month ago. In the house. Power supply was an ASTRON RS-70. Speakers were JBL LOFT-40. Amps? Kenwood XR400-4 (bridged to two channels, according to specs, should have been 200watts x 2 @ 4ohms), ADCOM GFA-4302 (2 channels rated @ 30watts x 2 @ 4ohms). 

Results? I sold the Kenwood. The ADCOM walked all over it. It was more dynamic. It sounded more transparent. And, it was much more detailed.

I am not against class-D. But, I am not sold yet. Mostly because, if there are class-D amps out there that do what you say yours does, Victor, I can't afford them!

I just picked up 3 Crossfire CFA-602's for less than $300. That is 1800watts of class-A/B fury, for $300. It is nostalgic. And, GOOD equipment is cheaper.

Don't get me wrong, I thought the size of that Kenwood was freakin' amazing! But, it sounded like ****, and was not making anywhere near 200watts.
Its brother, the 600-1 on the sub wasn't doing half bad though.


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## soccerguru607

Lycancatt said:


> this last post echos my approach as well. class a/b for everything I can, but with the levels of bass I want, its not remotely practical to use class a/b.
> 
> honestly I wish there were more class h car audio amplifiers like the qsc pro audio stuff I use and love.


I believe Arc and Genesis makes class G/H. Arc se2300 is an excellent sub amp.


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## gregerst22

PPI_GUY said:


> Good comments and observations guys. That's what I was hoping for instead of a AB vs. D crap storm. I've used both AB and D amps and in a moving vehicle, with road noise I can't tell any difference. Maybe I don't know what to listen for? Maybe I don't have a critical ear like a SQ judge might have?
> 
> But, honestly how many people compete in an environment where someone might notice? Most people...those you'll never see post here...just want a little extra bass in the hatch of their compact SUV. I'd think the number of people who buy a new (or near new) vehicle and want a full-bore system revamp is fairly small. Just look at the way brick & mortar stores are vanishing.
> 
> However, I will say that higher end companies still seem to be all-in on class AB amplification. That has to say something too. Are those companies (some heavy hitting, well known names) the last gasp of what we've come to call old school?


There have been SQ winning vehicles at the national level running all class d. For example Gary Summers, 4 time oscar winner for sound recording, ran all PDX when he won at nationals. Of course there have been plenty of not so famous people winning with all class d too.


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## soccerguru607

I am not surprised Class D amps like JL HD wins SQ competitions. You have to factor in the top of the line HU and DSP these guys are using. Many even modify them with better opamps, caps etc...Isn't HU and great speakers makes bigger difference in sound than amps? 

In my case using Victory Tube preamp completely changed how my amp sound. I have used plenty class D amps for subs but class D is just not for me when comes to mids/highs especially I do not ran any DSP, even my HU is simple type, Denford 8240.
I ran all my speakers straight to my amps so I get to hear exactly how certain set of speakers or amps sound. 

I had used JL hd 600/4 I did not like it for mids/highs but the next one I find I am going to see if I can modify it with better parts (my point of view) and see if makes a difference.


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## #1BigMike

I am going through a testing process currently with the Helix P6 amp. I must say, for what it is, it is fantastic. This is my first go at class D and I am pleasantly surprised. For those non purist (majority), this amp would be a perfect match. Its small, efficient, powerful and very warm sounding.

However, when I step into my wife's touareg that has A/AB amps throughout, there is a significant difference. 

As of right now, I am still going to go with the AB design for my main system. But I am so pleased with the Helix P6 that I will push those to my non "discerning" friends. 

Now whats going to be interesting, is what the helix P6 will produce once I throw in one of Victors tube pre amps. 

**Both systems have quality drivers which I feel is most important.**


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## 1996blackmax

I've been thinking of giving Victor's Tube preamps a try for a while. Maybe a little Christmas present for myself .


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## Victor_inox

High Resolution Audio said:


> It's switched on and switched off.


yes 400 000 times per second that is. your digital file you playing switched 44100 times per second. 
I don`t see a problem here. If you do why don't you playing vinyl records in your car? to be free of sample rate switching.


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## quality_sound

For me it's all about the clipping characteristics. 


Sent from my iPhone using Tapatalk


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## Victor_inox

1996blackmax said:


> I've been thinking of giving Victor's Tube preamps a try for a while. Maybe a little Christmas present for myself .


 I have zero returns so far and lifetime warranty.what do you have to lose?


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## Victor_inox

quality_sound said:


> For me it's all about the clipping characteristics.
> 
> 
> Sent from my iPhone using Tapatalk


what does that mean you like distortion?


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## 1996blackmax

Victor_inox said:


> I have zero returns so far and lifetime warranty.what do you have to lose?


Exactly! I will be going this route shortly sir .


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## Hillbilly SQ

I prefer a/b but would give the higher end fullrange d a chance in my own rig if one of my a/b amps went dead. I do admit that I'm still stuck in the past to some extent where class d on a sub was "dirty power" (my jbl bp600.1 sure was dirty) and the first run of fullrange d amps were cool for their size but not the best way to go if sq was your goal.


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## Victor_inox

1996blackmax said:


> Exactly! I will be going this route shortly sir .


 It make sound of Phoenix gold SD about the same as Brax Matrix, so I sold all my braxs shortly after. I still have some old school AB amps for sentimental reasons. 
I still love Pure class A amplifiers like mosconi A class and my own tubers.
If I`ve had classic car I`d install it there to have tubes glow for looks and unbeatable overloaded characteristics of single tube output.


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## ca90ss

From what I've seen posted over the years, when a system running class d amps sounds bad it's because of the amps, if it sounds good it's because of good speakers, placement, tuning etc. When a system with a/ab amps sounds bad it's because of bad speakers, tuning, placement etc. but if it sounds good it's because it's running a/ab amps.


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## Zippy

Victor_inox said:


> Its not an argument more of observation.Mark my word- in 15years there will be no class ab left in product lines of any major manufacturer. all of brands you mentioned have Dclass in production, they will eliminate AB slowly but surely. Class D became cheaper to make just as reliable if not better and can sound better then AB.


I'm going to have to disagree based upon what auto manufactures are doing. Cars that shutdown engines at stops, alternators that only run when battery charge drops below a certain point, electric cars that will loose driving range with a high powered stereo, 20+ speaker systems leveraging the 3 db increase for each additional driver, etc. I foresee a regression to the 60's class A amps power range(10-15 watts) with insanely efficient drivers. The future trend, as I see it, will be how loud and accurate can we get with minimal power. 

There are already some insanely accurate 5 watt speakers from Fostex that are more detailed than some high cost home audio systems. The imaging and clarity is off the charts for the cost. I'm even toying with the idea of making my next build a low powered system leveraging speakers like Fostex and Markaudio.


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## soccerguru607

One can't improve or innovate if one's heart and mind is not flexible to change for the better.


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## High Resolution Audio

Victor_inox said:


> yes 400 000 times per second that is. your digital file you playing switched 44100 times per second.
> I don`t see a problem here. If you do why don't you playing vinyl records in your car? to be free of sample rate switching.


The weekend before last, I went to the New York Audio Show. Before that, I preferred CD's to Vinyl. But then I was listening to Vinyl on a Gamut System ( Scan Speak Drivers ) on a Pear Audio Blue Turntable and then an Eric Clapton red-book CD went into the CD Player. To be it sounded harsh and I didn't care for it at all. I just got converted and became a Vinyl fan. 

Funny you mentioned this, because I was just thinking if it would be possible to be able to play Vinyl on my system. And maybe use a tube phono pre-amp. Is that what you sell?


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## Victor_inox

Zippy said:


> I'm going to have to disagree based upon what auto manufactures are doing. Cars that shutdown engines at stops, alternators that only run when battery charge drops below a certain point, electric cars that will loose driving range with a high powered stereo, 20+ speaker systems leveraging the 3 db increase for each additional driver, etc. I foresee a regression to the 60's class A amps power range(10-15 watts) with insanely efficient drivers. The future trend, as I see it, will be how loud and accurate can we get with minimal power.
> 
> There are already some insanely accurate 5 watt speakers from Fostex that are more detailed than some high cost home audio systems. The imaging and clarity is off the charts for the cost. I'm even toying with the idea of making my next build a low powered system leveraging speakers like Fostex and Markaudio.


maybe, maybe not. I don`t see what part you actually disagree with. my money is on low power high efficiency factory systems. My stock last gen 4runner speakers crazy sensitive and sounds half decent on about 5 real watt build in amp provide. they sounds even better on 50W class D amp I put them on.while taking about the same current.


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## Victor_inox

High Resolution Audio said:


> The weekend before last, I went to the New York Audio Show. Before that, I preferred CD's to Vinyl. But then I was listening to Vinyl on a Gamut System ( Scan Speak Drivers ) on a Pear Audio Blue Turntable and then an Eric Clapton red-book CD went into the CD Player. To be it sounded harsh and I didn't care for it at all. I just got converted and became a Vinyl fan.
> 
> Funny you mentioned this, because I was just thinking if it would be possible to be able to play Vinyl on my system. And maybe use a tube phono pre-amp. Is that what you sell?


 I don`t sell phono preamps, I`m thinking of adding one to my lines.
I make and sell tube class A preamps for use on 12V power.
front stage amplification is very important, like op amps. What you get out of your front stage that what you usually hear. power amp just amplified that signal.


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## Zippy

Victor_inox said:


> maybe, maybe not. I don`t see what part you actually disagree with. my money is on low power high efficiency factory systems. My stock last gen 4runner speakers crazy sensitive and sounds half decent on about 5 real watt build in amp provide. they sounds even better on 50W class D amp I put them on.while taking about the same current.


My disagreement is the migration to class D amps. I think that class D will be base audio systems, class AB will be upgraded, and class A high end. It's a matter of detail reproduction. Off a class A amp I can hear a saxophonist pressing the keys of his sax, off an AB amp I can hear it with the volume up if I know what to listen for, off class D it's just not there. Keep in mind, this is coming from someone running class D Hertz HDP amps in my BRZ for performance reasons. I wanted a minimal impact on my engines performance from my stereo, so efficient power was the way to go. Does my car image well and sound good, yes. Does it sound anywhere near as detailed as Bertholomey's BRZ running mosconi class A amps, hell no.


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## wheelieking71

Victor_inox said:


> Car audio people almost as conservative as musicians. to get them to new thing is about impossible regardless of reasoning, objective or subjective tests.


Ehh, I kinda agree. Old school codgers are stuck in their ways.
Case in point:
There are two aspects of car-audio I don't like. 
I don't care for heavy-cone, low-efficiency, small-box subwoofers.
I prefer efficient subs, in larger boxes.
And, I have yet to hear a class-D amp I like better than a good class-A/B.

Now, I have not heard very many full-range class-D amps.
And my truck is so damn noisy anyways, it wouldn't matter.

I am also one of those goofy old codgers that listens to 12v gear in the house. That is where I do critical listening.


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## wheelieking71

Zippy said:


> It's a matter of detail reproduction. Off a class A amp I can hear a saxophonist pressing the keys of his sax, off an AB amp I can hear it with the volume up if I know what to listen for, off class D it's just not there.


This pretty much sums up what my experiences have been as well.

My reference is an old-ass Acurus CD player, ADCOM GTP-400 pre-amp, and an equally old pair of DENON headphones. I don't remember the model# of the DENONs, but I bought them around 1988, and paid, I think $400. That was big money then. Well, I have a lot of CD's that I spent countless hours listening to through that combo. (I used to sit for countless hours on end building model cars) And, it revealed a lot of things hiding in recordings, that you normally wouldn't hear, or notice. There is a whole bunch of background noise hiding in a lot of recordings. I found lots of it.

And, I have definitely found that some amps reveal it better than others. And that is how I judge an amp.

Another thing I find funny. I have bought many an amp (mostly ADCOM's) where the seller was selling because it sounded like ****. Only to get it on the bench, and find the amp is all out of whack. Lots of DC voltage at the outputs. Of course it sounds like ****. Lots of guys are rocking equipment that isn't even in a proper state of tune.
One of the reasons I love ADCOMs as much as I do is because I know how to tune them back up. I am no amp tech! But, a good friend taught me how to adjust the bias and offset in ADCOMs. And, a few hours adjusting can sometimes turn an average amplifier, in to something extraordinary.


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## High Resolution Audio

Victor_inox said:


> I don`t sell phono preamps, I`m thinking of adding one to my lines.
> I make and sell tube class A preamps for use on 12V power.
> front stage amplification is very important, like op amps. What you get out of your front stage that what you usually hear. power amp just amplified that signal.


PM Sent.


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## DBlevel

Class a/b sounds better............


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## ChrisB

I used to be one of those closed minded, old school fools. I really thought they just didn't make them like they used to and spent a lot of time buying old amplifiers on eBay. That trend continued, until I made friends with someone who manufactured amplifiers here in Louisiana. Unfortunately, I originally made friends with him because my old relics needed to be repaired, but, he introduced me to Lunar. If I hadn't gotten into this compact car phase, I'd still be running Lunar, even though the brand is no more.

But, let's backtrack a bit. My discussions with Kenny basically brought me to the conclusion that full-range class d had come a long way since the Ice Power days. I was encouraged to try a JL Audio HD900/5 based on our discussions. After doing so and seeing the amount of power I could get in such a tiny footprint, I was totally converted. Now, I will admit that I was wrong to diss class d in general and full-range class d with the new offerings out there. Tiny cars with small engines, alternators, and batteries have no place for inefficient, space heating, class ab amplifiers these days. Plus, I'd be hard pressed to tell the topology of the amplifier at 30 MPH or faster. It's just a moot argument that those living in the past can't move forward on. They may as well keep bragging about their four touchdowns in one game 25, or more, years ago...


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## Victor_inox

Zippy said:


> My disagreement is the migration to class D amps. I think that class D will be base audio systems, class AB will be upgraded, and class A high end. It's a matter of detail reproduction. Off a class A amp I can hear a saxophonist pressing the keys of his sax, off an AB amp I can hear it with the volume up if I know what to listen for, off class D it's just not there. Keep in mind, this is coming from someone running class D Hertz HDP amps in my BRZ for performance reasons. I wanted a minimal impact on my engines performance from my stereo, so efficient power was the way to go. Does my car image well and sound good, yes. Does it sound anywhere near as detailed as barthlomey's BRZ running mosconi class A amps, hell no.


 I suggest you keep listening... I`ve had that mosconi Class A in my possession and put it on QSC ABX comparator (look it up)
While I think mosconi sounds as perfect as about any amplifier can be i was only be able to pick it 57% of the time with comparison to Brax Matrix MX4 (AB class) and 62% in comparison to Phoenix Gold SD series amp.
PG SD is nothing to write home about D class with switching frequency of 100Khz or so. Now If I put 650Khz switcher to compare I can`t get more then 52% accuracy on mosconi over D class. Mind you in each test I used my tube preamps in front of every amplifier I compared.
What to take out of that test is up to you. 
Class D made a long way since first switchers were introduced.
I have patent pending on SED class amplifier. Single ended D class. Very soon i`ll start offering them here.


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## Zippy

Victor_inox said:


> I suggest you keep listening... I`ve had that mosconi Class A in my possession and put it on QSC ABX comparator (look it up)
> While I think mosconi sounds as perfect as about any amplifier can be i was only be able to pick it 57% of the time with comparison to Brax Matrix MX4 (AB class) and 62% in comparison to Phoenix Gold SD series amp.
> PG SD is nothing to write home about D class with switching frequency of 100Khz or so. Now If I put 650Khz switcher to compare I can`t get more then 52% accuracy on mosconi over D class. Mind you in each test I used my tube preamps in front of every amplifier I compared.
> What to take out of that test is up to you.
> Class D made a long way since first switchers were introduced.
> I have patent pending on SED class amplifier. Single ended D class. Very soon i`ll start offering them here.


So, you were comparing all the amps with a tube preamp in front? Isn't that like giving each horse steroids before a race? The tube preamp will alter the results greatly. Especially in the preamp stage as is impacts the source signal. I'd like to know what the results are without the preamp. Just measuring pure amplifiers.


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## carlos3621

There's no winning this debate!
for me , it all comes down to personal sound preference.

I just swapped out an arc audio class D amp, for a sonfoni class AB amp, and immediately noticed the difference in the mids and highs, and that's not just BS , I can clearly hear the difference.
Im all for trying out new tech, and gave it a shot, but to me there was clearly a difference in sound quality, and so now, im back to class AB amps, making my install a lot more expensive due to size differences in amps.

trust me, I would have preferred to save money , but to me, the arc audio xdi amp, was harsh sounding and distorted at higher volume levels, compared to the sinfoni I replaced it with.

Now im sure that with DSP and EQ, and maybe different speakers, I could have made the arc audio amp sound better, but I personally prefer to keep my setup as simple as possible.
Or maybe the class D amps sound better with the right set of speakers to match the amps sound.

I just don't get why when anyone brings up this topic, people freak out and start spewing out that class d amps are better, when in fact, they are a COMPROMISE in design, to improve efficiency and size.

lets just realize that sound is a personal preference and some people prefer what they do, and it's nothing against one technology or another, but what sounds better to Their EARS!


----------



## Victor_inox

Zippy said:


> So, you were comparing all the amps with a tube preamp in front? Isn't that like giving each horse steroids before a race? The tube preamp will alter the results greatly. Especially in the preamp stage as is impacts the source signal. I'd like to know what the results are without the preamp. Just measuring pure amplifiers.


 I was testing preamp vs no preamp but amplifier test emerged from that.
Each of both amps has tube pre in front making them even. each side sonic signature was altered in the same way by equal amount.


----------



## Victor_inox

Victor_inox said:


> I was testing preamp vs no preamp but amplifier test emerged from that.
> Each of both amps has tube pre in front making them even. each side sonic signature was altered in the same way by equal amount.


What comparator does is to calibrate input of each amplifier so they get equal amount of power to speakers. then it switches between them and you have to guess what amp playing each time, after 20 takes it shows you how many times you guessed right.
I noticed that better speakers I used more accurate my guess gets.
That makes speakers most important for SQ component, not amplifier.


----------



## Zippy

Victor_inox said:


> I was testing preamp vs no preamp but amplifier test emerged from that.
> Each of both amps has tube pre in front making them even. each side sonic signature was altered in the same way by equal amount.


You narrowed the gap with the preamp. I know what my home audio system sounds like with and without my preamp. It makes a big difference.


----------



## ChrisB

carlos3621 said:


> I just don't get why when anyone brings up this topic, people freak out and start spewing out that class d amps are better, when in fact, they are a COMPROMISE in design, to improve efficiency and size.


I'll take this one step further. Car audio is a compromise! The position of the speakers to the listener are not equal; cars have odd resonances that must be dealt with or worked around; you've got reflections off the glass, plastic and other interior surfaces; and we can't forget refraction. Another major limitation is that of the electrical system, 12 volts (give or take) DC. Now let's take a look at newer cars with head units that can't be replaced, yet they have built-in processing that can't be defeated. Sure, some aftermarket processors account for this, but good luck on the units with volume dependent auto-loudness.

I'm sure I can come up with more compromises, but it is bed time!


----------



## quality_sound

Victor_inox said:


> what does that mean you like distortion?



No. It means I don't have the space to run the power I would prefer to have and during those times I do overdrive the amps I don't want it to sound like complete ass. 

And coming from someone that sells tube products, you condescending post is just a bit heavy-handed. 


Sent from my iPhone using Tapatalk


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## Victor_inox

quality_sound said:


> No. It means I don't have the space to run the power I would prefer to have and during those times I do overdrive the amps I don't want it to sound like complete ass.
> 
> And coming from someone that sells tube products, you condescending post is just a bit heavy-handed.
> 
> 
> Sent from my iPhone using Tapatalk


I`m sorry I`m confused, if you don`t have space to run power you prefer why not to run D class as smaller more efficient and more powerful? 
then you don`t have to overdrive your amplifier at all?


----------



## cajunner

this is the old tube soft clipping vs. the solid state hard wall, redux.

the class D amp is brick wall, you run clean and in a single click of detent on the volume knob, (if you are lucky enough to have a real volume knob) you are in a hell of distortion because there is no ramp up.

class AB amps take their time, you might get 2 clicks before distortion that is barely audible becomes raking leaves on concrete.

tube amps give you 4 clicks, it's all about how you like that adjustment window.

I'd like to be able to get tube amp distortion characteristics in the beautifully efficient switched mode class D architecture, maybe if someone were apt, or tuned in, they could do a circuit that instead of reducing negative feedback it could increase it so someone could think they were listening to an AB or even tube amp, when it was really a class D.


like guitar amp modeling, the psychoacoustics of clipping is the frontier, and not the baseline for making an amp sound the way most of us want it.

because most of us can appreciate distortion, if we're honest. We may attempt to scrub it from every component but that's only because we want to get loud first, before experiencing the sublime distortion, it's no good if it's convo level, that's where we're sensitive to it, that's where we pick it out and wonder about it. Get it up into the region of sound playback that you can't hear your own talking voice very well, and distortion is more accepted, it's integration... the euphonics are an envelope.


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## Victor_inox

You would be surprised but distortion characteristics often depends on power supply design. Once amp starving to more current it might exhibit weird distortion pattern.


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## wheelieking71

ChrisB said:


> I'll take this one step further. Car audio is a compromise! The position of the speakers to the listener are not equal; cars have odd resonances that must be dealt with or worked around; you've got reflections off the glass, plastic and other interior surfaces; and we can't forget refraction. Another major limitation is that of the electrical system, 12 volts (give or take) DC. Now let's take a look at newer cars with head units that can't be replaced, yet they have built-in processing that can't be defeated. Sure, some aftermarket processors account for this, but good luck on the units with volume dependent auto-loudness.
> 
> I'm sure I can come up with more compromises, but it is bed time!


Diyma needs a like button.


----------



## DDfusion

My take. With full range Class D, you get what you pay for. 
At least that's my opinion.
My 4 channel cost as much as a A/B of the same power. It's more efficient with a ton of headroom.


----------



## Guest

My take, Class D amps have really came a long way over the past few years...

For instance... The Helix P-six DSP... is a wonderful amplifier that sounds very good and has a TON of flexibility...

If I were building a system where space could not be taken up... that's the amplifier I would use...


----------



## kyheng

Some refuse to have their perception changed by what they believe all the while.
Something like I like to drink coffee every morning, I won't really like changing to drink coco.


----------



## quality_sound

Victor_inox said:


> I`m sorry I`m confused, if you don`t have space to run power you prefer why not to run D class as smaller more efficient and more powerful?
> 
> then you don`t have to overdrive your amplifier at all?



I'm not saying I won't run class d. I have before and will likely again. This thread is about preferences, not practicality. I'm not saying I use ab to get away with running smaller amps. I'm saying that at some point, unless you have many kilowatts of power, we ALL hit clipping occasionally and in that instance I much prefer ab. 


Sent from my iPhone using Tapatalk


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## quality_sound

cajunner said:


> this is the old tube soft clipping vs. the solid state hard wall, redux.
> 
> 
> 
> the class D amp is brick wall, you run clean and in a single click of detent on the volume knob, (if you are lucky enough to have a real volume knob) you are in a hell of distortion because there is no ramp up.
> 
> 
> 
> class AB amps take their time, you might get 2 clicks before distortion that is barely audible becomes raking leaves on concrete.
> 
> 
> 
> tube amps give you 4 clicks, it's all about how you like that adjustment window.
> 
> 
> 
> I'd like to be able to get tube amp distortion characteristics in the beautifully efficient switched mode class D architecture, maybe if someone were apt, or tuned in, they could do a circuit that instead of reducing negative feedback it could increase it so someone could think they were listening to an AB or even tube amp, when it was really a class D.
> 
> 
> 
> 
> 
> like guitar amp modeling, the psychoacoustics of clipping is the frontier, and not the baseline for making an amp sound the way most of us want it.
> 
> 
> 
> because most of us can appreciate distortion, if we're honest. We may attempt to scrub it from every component but that's only because we want to get loud first, before experiencing the sublime distortion, it's no good if it's convo level, that's where we're sensitive to it, that's where we pick it out and wonder about it. Get it up into the region of sound playback that you can't hear your own talking voice very well, and distortion is more accepted, it's integration... the euphonics are an envelope.



I actually agree with this. 


Sent from my iPhone using Tapatalk


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## thehatedguy

I used to be a class a/b guy forever type of guy until I tried the JL HD600/4. Changed me and my perceptions on full range class d. But like has been stated above, full range class d has recently come into it's own...and there are some really really good ones out there and a ton of really bad ones.

There really isn't as much innovation in a/b amps as there is in class d right now. The circuits being used are more than likely from the 70s with tweaks here and there...Victor would/could probably expound on that one much better than I could. New a/b will shift to g/h- RF did nearly 15 years a go. The new Oncore g/h amps Eric will be making will be like the future of a/b because they are really small and decently efficient. They will have to be because cars are not getting larger and room to install things is getting smaller with electrical demands getting larger.

But this class A thing in the car...I can count on one hand the number of class A amps and have fingers left over for real class A- not high biased a/b. And then most people are putting them on tweeters that play for like 3 octaves and the last whole octave has very little information in it. Why? Most people's speakers are not sensitive enough to really have any benefits from class A, especially the high biased a/b amps because they are out of class A operation after only a few watts...and then you are too loud to worry about crossover distortion and can't hear it (IMO).


----------



## carlos3621

kyheng said:


> Some refuse to have their perception changed by what they believe all the while.
> Something like I like to drink coffee every morning, I won't really like changing to drink coco.


I don't think this is true,

Like i said earlier, I would prefer to have a smaller and less expensive class d amp, im open and have tried to switch over,

BUT, they just don't sound as smooth on the higher frequencies as class ab.

So its not about being old school or whatever, its actually hearing the difference with your own ears. (Or not).


----------



## SkizeR

carlos3621 said:


> I don't think this is true,
> 
> Like i said earlier, I would prefer to have a smaller and less expensive class d amp, im open and have tried to switch over,
> 
> BUT, they just don't sound as smooth on the higher frequencies as class ab.
> 
> So its not about being old school or whatever, its actually hearing the difference with your own ears. (Or not).


he said some, not all. if you head over to facebook into one of those old school groups, you will certainly see what hes saying


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## Victor_inox

When first digital recordings started hitting the market true audiophiles started bitching about quantisation effect on sound quality. 8bit changed by16/32/48 bit system but they still ***** about quantization even though none of them can positively distinguish 16 bit recordings from 32bit. same phenomena happened with D class inception.
40-60-100KhZ was said as to be not clear sounding and was made for Sub duty. Then switching frequency started to go up but some manufacturers still have their power supply switching at 30Khz while raising amplifier switching frequency. 
JL HD and XD actually has floating SF for up to 400Khz from what i can see in their circuit. Point is not every D class created quail just like other classes. some better than others and class keeps evolving. I`m more concerned about lack of listenable new music then amplifier class.


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## wheelieking71

I need to get ahold of a JL HD. 

Full-range class-D amps I have heard:
ARC mini
ARC xdi
Alpine pdx (long time ago)
Kenwood XR (older model)
Kenwood XR (current model)

I think Kenwood actually took a step back. The rest sounded like **** to me.

Is the JL HD that much better that it would make me sway from class-A/B?
I am an open minded guy, and actually, it would be cool as hell if it was that good.

What full-range class-D on the market right now is as good as the JL HD?


----------



## gckless

cajunner said:


> this is the old tube soft clipping vs. the solid state hard wall, redux.
> 
> the class D amp is brick wall, you run clean and in a single click of detent on the volume knob, (if you are lucky enough to have a real volume knob) you are in a hell of distortion because there is no ramp up.
> 
> class AB amps take their time, you might get 2 clicks before distortion that is barely audible becomes raking leaves on concrete.
> 
> tube amps give you 4 clicks, it's all about how you like that adjustment window.
> 
> I'd like to be able to get tube amp distortion characteristics in the beautifully efficient switched mode class D architecture, maybe if someone were apt, or tuned in, they could do a circuit that instead of reducing negative feedback it could increase it so someone could think they were listening to an AB or even tube amp, when it was really a class D.
> 
> 
> like guitar amp modeling, the psychoacoustics of clipping is the frontier, and not the baseline for making an amp sound the way most of us want it.
> 
> because most of us can appreciate distortion, if we're honest. We may attempt to scrub it from every component but that's only because we want to get loud first, before experiencing the sublime distortion, it's no good if it's convo level, that's where we're sensitive to it, that's where we pick it out and wonder about it. Get it up into the region of sound playback that you can't hear your own talking voice very well, and distortion is more accepted, it's integration... the euphonics are an envelope.


Solid state guitar amps are still pretty far from a tube sound/feel, unfortunately.


----------



## thehatedguy

I like the JL HD amps...and I hated the Slash series with a passion. The HD line reminded me most of my Brax amps...pretty neutral, maybe a touch on the analytical side, with tons of balls. Talk about old school lineage with the JL HD amps- PPI glory days and Xtant heritage with the innovation of Power Physics technology. But some people might not like them.

The new Alpine PDXs are supposed to be up there with the JLs, but I haven't used one to know first hand. The older ones had some issues from what I remember.

The Arc minis- the KS amps are g/h, not class D.

What are the top dogs? JL HD and Alpine PDX are probably the top two in terms of engineering innovations. The new Arc xDi is a nice amp from what I hear as are the JL XD (but HDs are better). Oh, heard the Diamond Audio Hex amps are supposed to be really nice too, but you don't hear much about them around here. And then you probably have everything else since you have 10 companies pretty much using the same board from the same build house.

Someone else could probably add or take away from that above statement...amp shopping just isn't what it used to be for me. Not to say I wouldn't jump on some Brax, Sinfoni, Genesis, Steg etc if I could physically fit them in the car and could afford them.


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## thehatedguy

Ain't that the truth...but some are pretty good. I have an amp emulator that gets me close enough for the amount that I can still play to make me happy enough not to worry/want to change.



gckless said:


> Solid state guitar amps are still pretty far from a tube sound/feel, unfortunately.


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## Brian_smith06

Hatedguy you've run the ID amps correct? If so how would you compare them to the hd amps? If you're comparing brax to the jl amps then they cant be bad. 


I've always been an a/b guy but if the jl hd amps are that great I would be happy to get say a 600/4 and 900/5 and save an ass load of space. Maybe even mount in center console


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## thehatedguy

I had a trio of the 700.2s with the same mods as yours (I was Team ID  )...but only had one hooked up to the sub.

They were good amps, but out grew the trunk after I decided not to loose the spare tire.


----------



## PPI_GUY

thehatedguy said:


> Ain't that the truth...but some are pretty good. I have an amp emulator that gets me close enough for the amount that I can still play to make me happy enough not to worry/want to change.


Have a play on the Tech 21 Trademark amps sometime. You'll be surprised. I'm seriously looking at picking one up. Hughes & Kettner also makes a great SS. Maybe even look at a tube pre-amp pedal or rackmount in front of a quality SS power amp. 
I haven't found a emulator that has taken my breath away yet but, always open to suggestions.


----------



## PPI_GUY

Back to the "I hate class D" discussion...
Are we done seeing any progress or innovation in class A/B simply because D is the "hot thing"? Is the threshold of efficiency for A/B amps around 60% and that's about all we can ever expect? Hard to believe that's the case.


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## Brian_smith06

thehatedguy said:


> I had a trio of the 700.2s with the same mods as yours (I was Team ID  )...but only had one hooked up to the sub.
> 
> They were good amps, but out grew the trunk after I decided not to loose the spare tire.


that's what I thought. I always get you and howard mixed up since I have never actually spoken with either of you. 

I have to say my only complaint is just how damn big these amps are. You'd think with me having a Tahoe I wouldn't complain about the space, however, wife wont let me mount where I'd like. she says I have to keep the third row installed. I did somehow figure out a way to get to fit under second row but it is less than visually appealing. 

jl hd amps would fit the bill. but I have heard both sides of the whole class d debate. I guess I just need to let my ears decide


----------



## thehatedguy

I have a GNX4 that is older than dirt but has some really good "aftermarket" amp programs in it from some guy that used to do them years and years and years back. The Krank makes me happy enough that I haven't gone looking for anything else lately. I play through headphones and have a Paul Reed Smith HG70 half stack collecting dust.

My hands- the carpal tunnel from retail installing don't work the way they used to, so I don't play as much now as I did 15-20 years a go.



PPI_GUY said:


> Have a play on the Tech 21 Trademark amps sometime. You'll be surprised. I'm seriously looking at picking one up. Hughes & Kettner also makes a great SS. Maybe even look at a tube pre-amp pedal or rackmount in front of a quality SS power amp.
> I haven't found a emulator that has taken my breath away yet but, always open to suggestions.


----------



## quality_sound

I ran a 900/5 and 600/4 and they were great amps. Slight turn off pop, but other than that and those absolutely retarded plugs, they were great amps. I did, however, prefer my mosconi as's. They were more "fun." I'm not saying the difference was in the topology. They're both great amps but I'd probably try the new PDX's over the HDs just to not have to deal with those stupid plugs. 


Sent from my iPhone using Tapatalk


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## thehatedguy

I don't think so, but I see trends in size and efficiency over audio topology coming...as a general blanket statement.

Boutique brands are the exceptions to the rule.



PPI_GUY said:


> Back to the "I hate class D" discussion...
> Are we done seeing any progress or innovation in class A/B simply because D is the "hot thing"? Is the threshold of efficiency for A/B amps around 60% and that's about all we can ever expect? Hard to believe that's the case.


----------



## Brian_smith06

pdx would be much cheaper. maybe I can score a pdx v9 for cheap sometime soon and give that a go.


I have heard some people say this though and I can only assume myth? Just adding something to this topic. I don't agree or disagree seeing as I have no experience. 

it takes 300 watts of class d to equal 150 watts of class a/b


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## thehatedguy

Try a trunk of a Lexus IS300  And needing 12 channels of amps.



Brian_smith06 said:


> that's what I thought. I always get you and howard mixed up since I have never actually spoken with either of you.
> 
> I have to say my only complaint is just how damn big these amps are. You'd think with me having a Tahoe I wouldn't complain about the space, however, wife wont let me mount where I'd like. she says I have to keep the third row installed. I did somehow figure out a way to get to fit under second row but it is less than visually appealing.
> 
> jl hd amps would fit the bill. but I have heard both sides of the whole class d debate. I guess I just need to let my ears decide


----------



## Babs

While I've been quite pleased with my PDX's, I did hear some Class-AB amps at the last meet.. Dare I say the name.. Rockford. Yes.. THAT brand. These were in a very nicely built competition vehicle. One of our own, and one of the best cars I've heard yet. Power series AB amps. They did really well and there seems to be something there (not just the tune etc) that isn't with the PDX's. Regardless what class they were, I'd certainly consider them for a build. Look like quality amps. 

All that said, would be interested in what this business is about with their Power series Class "AD" design. 

RF states "AD topology brings out high efficiency bd amplifier design to a full range application. Class AD uses our Dynamic Frequency Switching to increase the switching frequency during lower output levels for better signal resolution. This coupled with Post Choke Feedback Filtering compares the input signal to the output signal at the speaker connector removing any unwanted distortion. These technologies eliminate the inherent switching noise associated with typical class D designs and also provide instantaneous output power over varying impedance loads"

Don't really have a dog in the race, but understanding that RF has been kind of a long-time marketer towards the SPL scene as opposed to the SQ scene, they don't get a lot of talk in these parts, which is kind of a shame. What I heard sounded dang quiet and dang clean and dang detailed, and they look quite well built and not so bad for their pricing. And while I could be dead wrong, if I had to guess RF doesn't strike me as the sort with their Power series at least to just buy build-house boards. Maybe their lower end stuff, but their top-line stuff I'd be willing to bet is in-house engineered and built. As said, I could be dead wrong on that.


----------



## Littlejerryseinfeld

wheelieking71 said:


> I need to get ahold of a JL HD.


Save yourself some time and money. They aren't anything special. I actually don't even like listening to them. About the most un-natural amp I've heard. Yes, I've owned a few. 



wheelieking71 said:


> Full-range class-D amps I have heard:
> ARC mini
> ARC xdi
> Alpine pdx (long time ago)
> Kenwood XR (older model)
> Kenwood XR (current model)
> 
> I think Kenwood actually took a step back. The rest sounded like **** to me.
> 
> Is the JL HD that much better that it would make me sway from class-A/B?
> I am an open minded guy, and actually, it would be cool as hell if it was that good.
> 
> What full-range class-D on the market right now is as good as the JL HD?



The Arc XDI v2 IMO. However, even Arc themselves will tell you they aren't anywhere near as good as the best A/B's. 

No one on this earth wants to spend more money, take up more space, and put even more stress on their electrical systems for no reason. The sound is not there with D. All the signal manipulation and internal need for passive crossovers isn't a lossless fix for all that's wrong with the class.


----------



## 1996blackmax

Babs said:


> While I've been quite pleased with my PDX's, I did hear some Class-AB amps at the last meet.. Dare I say the name.. Rockford. Yes.. THAT brand. These were in a very nicely built competition vehicle. One of our own, and one of the best cars I've heard yet. Power series AB amps. They did really well and there seems to be something there (not just the tune etc) that isn't with the PDX's. Regardless what class they were, I'd certainly consider them for a build. Look like quality amps.
> 
> All that said, would be interested in what this business is about with their Power series Class "AD" design.
> 
> RF states "AD topology brings out high efficiency bd amplifier design to a full range application. Class AD uses our Dynamic Frequency Switching to increase the switching frequency during lower output levels for better signal resolution. This coupled with Post Choke Feedback Filtering compares the input signal to the output signal at the speaker connector removing any unwanted distortion. These technologies eliminate the inherent switching noise associated with typical class D designs and also provide instantaneous output power over varying impedance loads"
> 
> Don't really have a dog in the race, but understanding that RF has been kind of a long-time marketer towards the SPL scene as opposed to the SQ scene, they don't get a lot of talk in these parts, which is kind of a shame. What I heard sounded dang quiet and dang clean and dang detailed, and they look quite well built and not so bad for their pricing. And while I could be dead wrong, if I had to guess RF doesn't strike me as the sort with their Power series at least to just buy build-house boards. Maybe their lower end stuff, but their top-line stuff I'd be willing to bet is in-house engineered and built. As said, I could be dead wrong on that.


I'm using Rockford Powers series d class amps & I'm happy with their performance. I know many people do not use them in sq installs, but they are solid amplifiers.


----------



## DDfusion

MS-8 for a size comparison. 
2700 watts of capable power here. 
It's not cheap but they are small, clean, and powerful.


----------



## #1BigMike

wheelieking71 said:


> What full-range class-D on the market right now is as good as the JL HD?



Look into the Helix P6. It really has surprised me.


----------



## Lycancatt

I too am a long time fan of the Rockford power series amps and actually would consider them a contender for any build needing solid power and recognizable branding.

also, I've heard a few systems with the jl hd amps, and heat issues aside which are considerably bad in two installs I heard, there sound just lacked something..just nothing that involved me and made me want to listen for long.

the newer pdx v9 and f4 in a friends install however were a totally different animal. I don't think i'll ever be a fan of class d, but these were as close as I think I'd ever get..followed by the arc xdv2 stuff which really isn't bad at all.

I'd love to do acomparison between lower end class a/b and midgrade to higher end class d, if only to see what my ears actually could tell me. reason for the lower end class a/b is that I know I like the higher end stuff, zapco, mosconi etc better, but how about the other end? I'm not talking about profile, American pro and the like, but powerbass, image dynamics, the basic kenwood series, and rf's punch lines of class a/b


----------



## Babs

DDfusion said:


> They are China amps. The efficency of the BDs is very low. They are consumer lines, nothing more.






1996blackmax said:


> I'm using Rockford Powers series d class amps & I'm happy with their performance. I know many people do not use them in sq installs, but they are solid amplifiers.



So on the standard class AB versions.. More better I imagine. Ones I heard sounded lovely. 

Makes me wonder if sending my old Kicker ZX700.5 (original version) in for service is worth it after all. Got an RA# but never got around to getting it to them. Got a channel that's wonky and I'm sure it could use some bench time. For a quick install beater amp if needed. Might be a fun combo also with the old Eclipse 3640 sitting next to it. 


Sent from iPhone using Tapatalk


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## 1996blackmax

I would send it in if they are covering the repair cost.

I ran Kicker amps, subs, & comps in the 90's....ZR/ZX amps...Solobaric S12D's...Resolution components....good gear.

That stuff lasted me for many years.


----------



## carlos3621

thehatedguy said:


> I used to be a class a/b guy forever type of guy until I tried the JL HD600/4. Changed me and my perceptions on full range class d. But like has been stated above, full range class d has recently come into it's own...and there are some really really good ones out there and a ton of really bad ones.
> 
> There really isn't as much innovation in a/b amps as there is in class d right now. The circuits being used are more than likely from the 70s with tweaks here and there...Victor would/could probably expound on that one much better than I could. New a/b will shift to g/h- RF did nearly 15 years a go. The new Oncore g/h amps Eric will be making will be like the future of a/b because they are really small and decently efficient. They will have to be because cars are not getting larger and room to install things is getting smaller with electrical demands getting larger.
> 
> But this class A thing in the car...I can count on one hand the number of class A amps and have fingers left over for real class A- not high biased a/b. And then most people are putting them on tweeters that play for like 3 octaves and the last whole octave has very little information in it. Why? Most people's speakers are not sensitive enough to really have any benefits from class A, especially the high biased a/b amps because they are out of class A operation after only a few watts...and then you are too loud to worry about crossover distortion and can't hear it (IMO).


just wondering...
what type of speaker setup are you running now , with your JL HD amps?


----------



## Babs

1996blackmax said:


> I would send it in if they are covering the repair cost.
> 
> I ran Kicker amps, subs, & comps in the 90's....ZR/ZX amps...Solobaric S12D's...Resolution components....good gear.
> 
> That stuff lasted me for many years.



Nah I'd be covering it. This thing is old. I picked it up back in 2011 or so for like $150. I bet still worth it. Sounded great when it ran all channels. Pushed an old kicker CVR 12 pretty good as well. 


Sent from iPhone using Tapatalk


----------



## 1996blackmax

Give it a go! Bring that puppy back to life.


----------



## kyheng

carlos3621 said:


> I don't think this is true,
> 
> Like i said earlier, I would prefer to have a smaller and less expensive class d amp, im open and have tried to switch over,
> 
> BUT, they just don't sound as smooth on the higher frequencies as class ab.
> 
> So its not about being old school or whatever, its actually hearing the difference with your own ears. (Or not).


Well, I'm with you on this, that's why my front stage still using class A/B amps, you need very high frequency range for class D amp in order for the midrange and tweeter to play smoothly. That range is something like 20-192000Hz.
Earlier fullrange class D are not that good on this. Now should be better. Still, some steps needed. That's why RF come out with various types of amps.


----------



## TOOSTUBBORN2FAIL

If you need 192000hz switching frequency, are you listening to high resolution formats? Because that's 4 times the sampling rate of a cd.

Actually a better question. Do you think the jl HD makes the tweeter sound less smooth than an ab amp? And if so, how is that related to switching frequency, when it switches at 9 times the sampling rate of a cd?


----------



## thehatedguy

What frequency is the antialising filter in your DACs?


----------



## ssclassa60

Back on track....

I despise Class D because they're tiny and don't get hot. I want a high bias AB amp that idles at 9amps and needs 2 feet of heat sink to get rid of the 50% wasted energy shed as heat. I want an amp that is rated at 50x2 but has 1400W of output transistors just in case. This is like comparing an old L88 Corvette to a Prius


----------



## sqnut

If you try and make the sound more airy than the recording, you'll end up with brittle sound. Try boosting 12-20khz on your eq into the +ve zone. What am I going to do with an amp that has more omph past 20 when most tweeters are taking a nosedive past ~15?


----------



## ssclassa60

Littlejerryseinfeld said:


> You could cook an egg on a JL HD. That heat isn't appearing for no reason.



I stand corrected on the heat part. Makes sense the heatsink would be sized to whatever the max dissipated heat is.

I stand by my other statements tho...


----------



## thehatedguy

Only that particular Prius has as much HP as the Vette, go faster, get better gas mileage, has better brakes, tires, and suspension.



ssclassa60 said:


> This is like comparing an old L88 Corvette to a Prius


----------



## ssclassa60

thehatedguy said:


> Only that particular Prius has as much HP as the Vette, go faster, get better gas mileage, has better brakes, tires, and suspension.


Bear in mind I've yet to listen to a full range Class D, and I only am a fan of high bias 'Class A' AB amps. 

Is there a class D amp that sounds as good as my Adcom 4404, has the same headroom, and dynamic capabilities? Please let me know so I can take a listen. Based on this thread I might have to switch my sub amp to class D as I'm running out of room....


----------



## thehatedguy

I owned a trio of 4302s back in like 94-95ish...and were good amps, could drive the snot out of them- we bridged one on the display board to 1/8th ohm and she kept going. While I liked the amps, I did not think they had a lot of balls to them. 

But what are you calling high bias "Class A" amps? My Monolithic A501Ms are very high bias A/B and they could burn your hand from the heat- they get so hot you can smell them in the car.

I've been lucky enough over the years to have owned a pair of Brax Graphic amps 2 of 500 in the world, few Brax SPL Comps, X2400, X1400, Milbert BAM230, the Monolithics, have a HSS HT230 Class A tube amps, Zapco Z600C2s, Reference, and DC Reference, Linear Power 2.2s, 3.2s, and 4.1s, US Amp TU4360, TU600, 1000X (awesome amp), JL Slash series (hated them...made me hate class D amps), JL HD 600/4s (great amps, nothing like the Slash series), and godknows how many RF, Orion HCCA, HiFonics Series 7s, Autotek 9050BTS...

And I am saying to me, on that last system, the JL HDs reminded me most of my Brax amps. Great amps but those plugs will make you want to slap someone.



ssclassa60 said:


> Bear in mind I've yet to listen to a full range Class D, and I only am a fan of high bias 'Class A' AB amps.
> 
> Is there a class D amp that sounds as good as my Adcom 4404, has the same headroom, and dynamic capabilities? Please let me know so I can take a listen. Based on this thread I might have to switch my sub amp to class D as I'm running out of room....


----------



## ssclassa60

thehatedguy said:


> I owned a trio of 4302s back in like 94-95ish...and were good amps, could drive the snot out of them- we bridged one on the display board to 1/8th ohm and she kept going. While I liked the amps, I did not think they had a lot of balls to them.
> 
> 
> 
> But what are you calling high bias "Class A" amps? My Monolithic A501Ms are very high bias A/B and they could burn your hand from the heat- they get so hot you can smell them in the car.
> 
> 
> 
> I've been lucky enough over the years to have owned a pair of Brax Graphic amps 2 of 500 in the world, few Brax SPL Comps, X2400, X1400, Milbert BAM230, the Monolithics, have a HSS HT230 Class A tube amps, Zapco Z600C2s, Reference, and DC Reference, Linear Power 2.2s, 3.2s, and 4.1s, US Amp TU4360, TU600, 1000X (awesome amp), JL Slash series (hated them...made me hate class D amps), JL HD 600/4s (great amps, nothing like the Slash series), and godknows how many RF, Orion HCCA, HiFonics Series 7s, Autotek 9050BTS...
> 
> 
> 
> And I am saying to me, on that last system, the JL HDs reminded me most of my Brax amps. Great amps but those plugs will make you want to slap someone.



Ok so JL HDs then, I'll have to take a listen thank you. I got my definition of Class A push pull amps from Nelson Pass, great article:

http://www.firstwatt.com/pdf/art_leave_classa.pdf

In summary, all AB amps operate in Class A up until the point where output current is twice the idle current. High bias (aka high current) amps stay in Class A longer.

I agree the Adcoms arent monsters, but are the most musical car amps I've listened to (as are the home Adcom GFA high current lineup, especially the Pass designed 555).

Soundstream class A 6.0's have alot more headroom than the Adcoms but arent as musical imo. As I'm sure you know these are also good to 1/4 ohm or less. These amps are very similar in concept to the Linear Power, Orion, and other high current amps you mentioned.
The Adcom 4404 idles at around 9amps! The 6.0's around 4 so they also operate in Class A up to a pretty high output. 

You've been lucky to listen to quite a few great amplifiers, that Brax must have been pretty epic! Curious if you ever measured its idle current?


----------



## thehatedguy

Oh speaking of Nelson Pass, I built a couple mini Alephs and used the power supplies and heatsinks of my Monolithics...15 watts of single ended solid state class A. Sounded great. Not tube great, but really good. Way too little heatsink though.

And you know Pass had a hand in the Adcom car amps? 

The Brax was nice, they all were. The Platinum editions that I had finish was horribly thin and seemingly would scratch if you sneezed on it. Anyways I took them out not to soon after some crackheads tailgated me for like 10 miles in BFE...they were so close that I couldn't see their head lights in my rearview. And being so rare, I knew I couldn't replace them if something had happened.

Those particular amps had a Graphic 4 channel board and a regular X2000 board in them. I was having problems with the RCA terminals and my tech repaired them. He benched the amp and he commented on how high the idle current was. I don't recall what it was exactly...it was high for an a/b, or at least he wasn't used to seeing a/b amps coming through that were not biased towards b rather than a/b.


Well, I have been thinking about this since my last post. I think I like the JL HDs so much because I had a really bad experience with the Slash amps and had a preconceived notion class D sucked...and they didn't. They were quiet, had lots of power, and had no noticeable sound to them. The Slash amps for whatever reason (I don't know a scientific reason why) had no dynamics to them...I really really disliked them. But one developed a pop and I wasn't the original owner...sent it to JL and for a little money they sent me a new amp (or a new board in my heatsink).


So I might have a love affair with them because they were the first that I experienced. Some people like other full range class Ds better like the Alpine and Arcs. So there might be better on the market, my sample size with full range class Ds is rather small. So take everything with a grain of salt.

There are a lot of nice class Ds on the market. If you don't need to bridge, the Biketronics seem to be nice and they are based on Hypex modules.

I am curious as to what is out there, I might find something better than the JL.


----------



## PPI_GUY

Littlejerryseinfeld said:


> Progress in what way? All A/B amps are not equal in sound so there are always going to be new designs trying to get the best sound.
> 
> As far as efficiency; who cares? I've ran A/B amps for the past 20 years and have had to replace an alternator just as often as a guy that has a stock system in his car. It's really not an issue. It's not like just because you run class A/B you have to consider a bunch of extra car maintenance costs. It's not an issue.


Progress in the design, size and efficiency of A/B amps Is approx. 60% the max efficiency possible with an A/B amp? If so, is there a electrical law that dictates that? After all, it was only a few years ago that class D amps were undesirable because their power supply switching was too slow along with poor performance in the upper registers.

Are A/B amps doomed to always be much larger than class D? Will continuing advances in SMT (and possibly more efficient power supplies) allow class A/B amps to reduce their footprint? 
When you get beyond a certain power level (different with every vehicle model) you are going to have to augment your stock electrical charging system. Maybe even add extra power storage. I'm not talking about SPL systems necessarily either.

The only real change I've seen in class A/B amps since 1987 is a move from hand assembly to automation and surface mount components. There's probably two camps on that process as well. LOL!


----------



## Babs

Yeah the Hypex design seems to get good props. Id rock one of those biketronics amps on my Hard-Ball in an instant if I had a solution where speakers would go. Prolly good thing she's without a full fairing or I'd be doubly broke.

















Sent from iPhone using Tapatalk


----------



## thehatedguy

Eric Stevens of Oncore (formerly of Image Dynamics) is releasing an 8x100 (or was it 8x150?) g/h amp that is about the size of a piece of notebook paper- like 9x14 or something small like that. There will be a matching 1500 watt mono block that will be the same size.

If you are fan cooling, you can loose some heatsink...but are at the mercy of the fans.



PPI_GUY said:


> Progress in the design, size and efficiency of A/B amps Is approx. 60% the max efficiency possible with an A/B amp? If so, is there a electrical law that dictates that? After all, it was only a few years ago that class D amps were undesirable because their power supply switching was too slow along with poor performance in the upper registers.
> 
> Are A/B amps doomed to always be much larger than class D? Will continuing advances in SMT (and possibly more efficient power supplies) allow class A/B amps to reduce their footprint?
> When you get beyond a certain power level (different with every vehicle model) you are going to have to augment your stock electrical charging system. Maybe even add extra power storage. I'm not talking about SPL systems necessarily either.
> 
> The only real change I've seen in class A/B amps since 1987 is a move from hand assembly to automation and surface mount components. There's probably two camps on that process as well. LOL!


----------



## Lycancatt

as I sit here with my 30 plus year old sansui au217 integrated class a/b amp rocking out powering my big 3 way passive boxes with a class d sub amp powering my sub, halfway down a bottle of burban, I cant help but think if I was listening to a new class d super efficient amp if I'd be as happy with what I'm hearing. call it drunk thoughts but seriously, theres just something that engages you as a listener with class a/b or even class a that just isn't there with class d, I ****ign wish I could pinpoint it to combat/better it because what I want to build next year is almost going to require class d to work.


----------



## ChrisB

thehatedguy said:


> Huh...the three I had got no where near that hot.


Yeah, but I had some Orion HCCA 225s that you could grill hot dogs on when you bridged them at 1 ohm and blasted the ever living hell out of them. :laugh:


----------



## ssclassa60

Yeah, Pass had his hand in quite a few amps I desire or have a handful of. Nakamichi, original Soundstream Class A, D, MC series, and then Adcom.

So I'm starting to hear that quite a few people here prefer old school high current AB amps at least in SQ...


----------



## Littlejerryseinfeld

ssclassa60 said:


> Yeah, Pass had his hand in quite a few amps I desire or have a handful of. Nakamichi, original Soundstream Class A, D, MC series, and then Adcom.
> 
> So I'm starting to hear that quite a few people here prefer old school high current AB amps at least in SQ...


A/B.... Not just "old school" A/B.


----------



## hurrication

Lycancatt said:


> call it drunk thoughts but seriously, theres just something that engages you as a listener with class a/b or even class a that just isn't there with class d, I ****ign wish I could pinpoint it to combat/better it because what I want to build next year is almost going to require class d to work.


It's called psychoacoustics.


----------



## XSIV SPL

Sorry, I haven't read this whole thread... I actually stopped reading it about 2/3 of the way through the first page.... So please forgive me if I've ignored a strong argument for running D-class amplifiers in any good system.

Every class of amp has its own virtues. If you're serious about SQ, you probably have no D-class anything in your system.

I'd elaborate, but I think this pretty much covers it.


----------



## ImK'ed

Im running a jl hd 900/5 in a simple 2 way plus sub and it sounds as good as any class a/b system ive heard or ran myself. But ive only heard decent middle class a/b amps not high end exotica. Before this jl amp i was running a ti21600.5 and that was another amazing class d amp only reason i sold it was because of some build issues ( over tightened screws on terminal plastics ) and my ocd wouldnt allow me to keep it, but i think i see one in my near future again. 

One thing that did make me think was that the ti2 wasnt the top tier in pgs line up, its the elite and they are class a/b. Pg themselves say the ti2 can rival some of the best class a/b amps out there but they still build class a/b as theyre top end. I wonder if they did this because of nostalgia knowing that some of the old skool fans especially old skool pg fans would loose their mind when they saw an amp built to be the best (and to these old skoolers it has to be class a/b) or they did this because they still believe a/b has an edge dunno? 

I remember reading a review on the ti2 amp on the pg phorum and that guy was one of the active members on there with alot of amplifier experience forgot his name now, but he said the ti2 was the best pg amp he had heard except for the elites.


----------



## kyheng

Class D's frequency range needs to be /8, after the calculation, it is about 24000Hz.


----------



## wheelieking71

ssclassa60 said:


> Bear in mind I've yet to listen to a full range Class D, and I only am a fan of high bias 'Class A' AB amps.
> 
> Is there a class D amp that sounds as good as my Adcom 4404, has the same headroom, and dynamic capabilities? Please let me know so I can take a listen. Based on this thread I might have to switch my sub amp to class D as I'm running out of room....


Funny, we have basically the same outlook, even the same reference amp.
Myself, being an ADCOM aficionado for a long-long time, I have yet to hear any amps that were "better". For the same reasons you mention:
Tons of head-room, killer dynamics, yet still very transparent, and just all around great amps.
I overcame the minuscule power on tap by bridging pairs. Best two way front stage power I have ever experienced to this day was a pair of 4302's bridged on tweets, and a pair of 4402's bridged on mid-bass.
It was incredible, and enough power for anybody.
I liked bridging the two channel amps simply because I figured two more fans couldn't hurt, and mounting was usually easier. The ONLY! draw back? Space. Those four ADCOM's took up a lot of room. 

Have I heard amps that sounded "as good" as my beloved ADCOM's?
Sure!
SoundStream D200 I&II
SoundStream REF Class-A 6.0 & 3.0
MB Quart QAA-2500 (made by Rockford, total beast mode amp. But, at low volumes sounded wonderfull)
TRU S44
BRAX X2000spl (very transparent, linear, power. Just dial in as much as you want. It had it. Best amp I ever owned probably)
HELIX (I don't remember the model)
MMATS LM2125 (this was a huge surprise, killer amp!)
Never heard an ADS amp I didn't like. (probably owned 5 of them)

Have I owned High-end status amps that let me down?
YEP!
Linear Power 2.2HV
McIntosh MC425
JL Audio 300/2
Orion "beast"

All duds in my opinion.

And, to this day, I have yet to hear a full-range class-D (or any class other than A/B for that matter) that I like.

I would sure like to find one though. As I get older, installing huge amps has lost its luster for sure!

Disclaimer: Since I am spouting off about my opinion, I probably should note that most of my listening experience that I use to form these opinions has been based in the house!
NOT in the hostile automotive environment.
Yes, I am one of those weirdos that likes to "play" with 12v stuff in the house.


----------



## thehatedguy

You might want to tell Mark Elridge that since there are few less serious about SQ than him and he has a NASCAR load of JL HD amps.



XSIV SPL said:


> If you're serious about SQ, you probably have no D-class anything in your system.
> 
> I'd elaborate, but I think this pretty much covers it.


----------



## DDfusion

And Scotts G35. All class D. I'd imagine you see more class D than AB these days.


----------



## TOOSTUBBORN2FAIL

kyheng said:


> Class D's frequency range needs to be /8, after the calculation, it is about 24000Hz.


Jl hd's switch at 400,000.


----------



## DDfusion

I swapped out my 450/4v2 with a HD600/4 a few years ago. I put the 450/4 back in. 
I don't know what my SS4A is spec wise but it's better to my ears than the HD was but not as good as the 450/4.


----------



## Victor_inox

TOOSTUBBORN2FAIL said:


> Jl hd's switch at 400,000.


So is XD and it`s up to 400Khz not fixed.

That was cool 8 years ago, today much faster switching available. JL won`t change what`s not broken but nonetheless faster more efficient switches is here. 
I have one operating at up to 800KHz and 97% efficiency.


----------



## thehatedguy

Victor, when are you going to have 12 channels ready to go?


----------



## ImK'ed

Victor_inox said:


> So is XD and it`s up to 400Khz not fixed.
> 
> That was cool 8 years ago, today much faster switching available. JL won`t change what`s not broken but nonetheless faster more efficient switches is here.
> I have one operating at up to 800KHz and 97% efficiency.


You have a custom amp or a modified one running like that?


----------



## Victor_inox

thehatedguy said:


> Victor, when are you going to have 12 channels ready to go?


 As soon as I resolve slight pop on turn off. it`s minor but it`s there.


----------



## Victor_inox

ImK'ed said:


> You have a custom amp or a modified one running like that?


My own design.


----------



## ImK'ed

Victor_inox said:


> My own design.


Kewl! Good stuff


----------



## 1996blackmax

XSIV SPL said:


> Every class of amp has its own virtues. If you're serious about SQ, you probably have no D-class anything in your system.
> 
> I'd elaborate, but I think this pretty much covers it.



Couldn't be more mistaken....


----------



## ssclassa60

Littlejerryseinfeld said:


> A/B.... Not just "old school" A/B.


I only say old school because there were so many more high bias A/B amps on the market then during the whole cheater amp phase in IASCA.

I think Nelson Pass would agree that sonic performance and bias current are proportional while distortion and bias current are inversely proportional. If you want the best sound from an AB amp, you want as much bias as humanly (thermally) possible.

Also I find that few, if any modern AB amps run with very high bias. The Sinfoni "Class A" monoblocks idle at less than 2A. In my limited exposure to modern amps, only Brax and Tru would really compare with the old school high bias configuration - and they are ultra expensive.

If there are other modern amps running high bias, especially at a reasonable cost, please let me know.


----------



## Victor_inox

What is reasonable cost? that disclaimer alway make me chuckle a bit. 
Is Mosconi A reasonable? I`m not sure what you tried to say about mosconi A.


----------



## wheelieking71

thehatedguy said:


> The Brax was nice, they all were.
> 
> Those particular amps had a Graphic 4 channel board and a regular X2000 board in them. I was having problems with the RCA terminals and my tech repaired them. He benched the amp and he commented on how high the idle current was. I don't recall what it was exactly...it was high for an a/b, or at least he wasn't used to seeing a/b amps coming through that were not biased towards b rather than a/b.


The Brax X2000 that I had, was I believe somehow tied to you. I got it as a bare board from DAT, and then machined a custom heat-sink for it. It idled at right around 10 amps.


----------



## Victor_inox

It shouldn`t be idling that high, it was altered somehow.


----------



## lust4sound

turbo5upra said:


> Because they haven't taken the time to a/b them...


LOL!!


----------



## ssclassa60

wheelieking71 said:


> The Brax X2000 that I had, was I believe somehow tied to you. I got it as a bare board from DAT, and then machined a custom heat-sink for it. It idled at right around 10 amps.


And my Adcom 4304 and 5450 and GFI 4600 are tied to you


----------



## ssclassa60

Victor_inox said:


> What is reasonable cost? that disclaimer alway make me chuckle a bit.
> Is Mosconi A reasonable? I`m not sure what you tried to say about mosconi A.


Yes I know sorry - reasonable cost when talking high end SQ is a bit contradictory...

Iirc Tru and Brax are in the $2k+ range which is cost prohibitive.
Back in the late 90's, a SS Class A 6.0 was $600 which was expensive for the time but reasonable. The Adcom's almost priced themselves out of the market at $800+ back then.

I would say anything under $1250 in today's money would be 'reasonable'. 

And I was saying the Sinfoni Class A monoblocks idle at a pretty low amperage to be called "Class A"...


----------



## lust4sound

SkizeR said:


> to add what the other guys said, they will say that stuff now "isnt made like it used to be", or american made stuff is better, or whatever. i actually think if you compare apples to apples now, the newer stuff is better. what ive noticed from the majority of them are just stuck clinging to the past back when their cars were worth talking about and have a crazy superiority complex where they automatically think your an idiot for using class d, or a dsp, or anything else from after the turn of the century
> 
> 
> also, sub'd for the foreseeable ****storm approaching


Amp tech has come a long way. Amps are so much more efficient these days, many are being made much cheaper, consume less current, put out more power, and have SQ to match their predecessors.. 

I too am an advocate for Old School amps.. I absolutely swear by them.. But there's no ignoring the facts..

I also had an in depth conversation with a certified electronics repair tech, who also has a degree in engineering.. He's been in the business of repairing amps for the past 25 years, in South Florida, he's the best in the game..

I showed him an old school Zues amp (series VII I believe) 

What he told me was not only a surprise, but a complete shock.. He told me, that for the money it would cost to repair that amp, I could just throw a few bucks on top and pick up what was essentially a flea market brand and get better results (if it didn't break down due to poor quality control or build)

(I don't recall the amp he showed me, this was a few years back, I think it was an new Lanzar)

He basically told me that it is cleaner and more efficient than the old school Zues, AND THIS WAS ONE OF THOSE FLEA MARKET SPECIALS WHICH HAVE THE WORDS 5000 watts Max printed on the front of the amp.. Of course he explained that the amp was legitimately only 600 watts RMS (or some ridiculous number which I can't recall, but it wasn't anywhere near 5000 watts of usable power.. Not even 1000 watts) but in comparison (both price wise, in terms of efficiency and sound quality, the new flea market cheapy had the Zues outmatched in every way)

The only drawback is the **** build quality and or quality control.. That the amps broke down for the stupidest of reasons (reliability is an obvious issue) He went on to tell me that if you get hold of one which works, as long as it's properly implemented, will continue to work with no issues!

LOL

Still, I am partial to old school PPI Art or anything PPI from the late eighties, early 90s, anything pre PC (some of the US made PC's as well) Phoenix Gold MS, Soundstream Reference and especially the D200II for midrange in active systems..

As for class D, I love it for subs.. There's no getting around the huge power and efficiency, excellent woofer control (SQ) and finally, the tiny footprint..

Anyone with experience with Mmats amps?? Their older amps are absolute monsters for subs, in terms of efficiency, footprint and SQ, they are tough to beat.. D class.. Now dig further back, their older amps (SQ oriented) use T-03 switching devices and have absolutely spectacular sound quality (older 2 and 4 channels, square, black or white, LM series I believe.. If you're looking for a beast of an amp which will cleanly and precisely power a 1 ohm load in the 2khz and up power range, without the need for a fusion reactor in tow to power it, look up MMats D2000, D3000, D3500 amps.. They are brushed aluminum with curved sides, have the MMats logo cut out in the centers backed by metal mesh (cooling) These amps are absolute thunder, do proven rated and more, and are more than 75% efficient.. I had a pair of the D3500.1 powering 4 of the first gen Solobaric 15s (1 amp per pair of subs, 1 ohms per side) With a stock alternator, 4 gauge wire and 2 gelcaps, I was able to push these subs easily to exceed their mechanical limits (if not careful) After careful tuning and install, the output was ludicrous.. 6000 watts RMS spread across 4 15" solobarics in a 12 CF enclosure tuned to 26hz.. MY GOD.. Woke my neighbors and pissed off the dead.. You can score one of those preowned for around $400 to $500 on Feebay.. Their older LM series amps with the T-03s? Good luck finding one, if you do, SNAP IT UP.. They give Linear Power a run for their money.. 

I haven't read the whole 8 pages of this thread, but that's my partially off topic rant regarding the matter..

I'm presently running a complete set of Fosgate Punch A series amps for a 3 way active system.. I don't love them.. As a matter of fact, I'm selling all 4 (1 needs a doctor)

Anyone interested in some minty A series Fosgate Punch amps, PM me!!


----------



## ssclassa60

Victor_inox said:


> It shouldn`t be idling that high, it was altered somehow.


With the custom heat sink, I'm sure they maxed out the bias pots. 10A is not crazy for a larger high bias amp. Like I said before the Adcom 4404 spec is 9A and the 4702 spec was 10A

I like Nelson Pass's guideline of maxing out bias to a 30deg C heatsink rise from ambient at idle.


----------



## lust4sound

As for Mosconi, Sinfoni and the latter of the upper echelon amps, I have limited experience with them, sorry, didn't know the thread already went there..

Have a friend who is a Mosconi dealer, he owes me a big favor, for a limited time, I can get Mosconi and Focal at far less than retail. Brand new in boxes W warranty (for a limited time)


----------



## thehatedguy

There's this forum member who uses class D in his car:

Gary Summers - IMDb

So please...please elaborate because I think it would be fun.



XSIV SPL said:


> . If you're serious about SQ, you probably have no D-class anything in your system.
> 
> I'd elaborate, but I think this pretty much covers it.


----------



## wheelieking71

lust4sound said:


> Anyone with experience with Mmats amps?? Their older amps are absolute monsters for subs, in terms of efficiency, footprint and SQ, they are tough to beat.. D class.. Now dig further back, their older amps (SQ oriented) use T-03 switching devices and have absolutely spectacular sound quality (older 2 and 4 channels, square, black or white, LM series I believe..


I am currently playing with an LM2125 in the house, and it has more than impressed me!


----------



## thehatedguy

Yeap you are right...I remember mine idling high. I was thinking it was around 9-10 amps when my tech had it on the bench replacing the RCA inputs. He was like, holy crap 9 amps of idle current.

But no, it wasn't altered by me- that's the way they came from Germany and then to Peter Lufrano...then to me.



wheelieking71 said:


> The Brax X2000 that I had, was I believe somehow tied to you. I got it as a bare board from DAT, and then machined a custom heat-sink for it. It idled at right around 10 amps.





Victor_inox said:


> It shouldn`t be idling that high, it was altered somehow.


----------



## Victor_inox

wheelieking71 said:


> I am currently playing with an LM2125 in the house, and it has more than impressed me!


what happened to the pictures you attached?


----------



## thehatedguy

No, they were not altered by me and ran like that when I got them.

The reason it came without a heatsink was I had done some board swapping to get me in the correct power class in IASCA- I swapped SPL Comp (high current version of the X2000) boards in for either the X2400 or X2000 side...I don't remember and misplaced the heatsink for the board DAT got, so he bought a heatsink for it.

I would say it was a Team Brax factory modification as at the time I was on Team Brax...but I didn't join the team until after I already had the amps.



ssclassa60 said:


> With the custom heat sink, I'm sure they maxed out the bias pots. 10A is not crazy for a larger high bias amp. Like I said before the Adcom 4404 spec is 9A and the 4702 spec was 10A
> 
> I like Nelson Pass's guideline of maxing out bias to a 30deg C heatsink rise from ambient at idle.


----------



## Victor_inox

That would make sense then.


----------



## thehatedguy

They were, hands down the overall best amps that I have owned- the HSS on some high efficiency speakers is THE best that I have owned/still own. Had a Sinfoni rep reach out to me in like 02 or 03 or so to run their amps, but had just agreed to a deal with another company to use their amps...and I'm not the type of person to reneg on deals like that, so I didn't pick any of those up. Wanted to get some Genesis as my friend Ron Buffington was sponsored by them and knew Gordon personally...but the "next" rebuild sort of stalled for a number of years, Genesis went out of business and I got picked up by Zapco.


----------



## wheelieking71

Victor_inox said:


> what happened to the pictures you attached?


I yanked it real quick, second thought, didn't figure I should clutter the thread.
I can put it back.
Also have pics of hatedguy's old Brax in custom heat-sink. (kick myself daily for selling it)


----------



## thehatedguy

Know what you mean...



wheelieking71 said:


> Also have pics of hatedguy's old Brax in custom heat-sink. (kick myself daily for selling it)


----------



## Victor_inox

wheelieking71 said:


> I yanked it real quick, second thought, didn't figure I should clutter the thread.
> I can put it back.
> Also have pics of hatedguy's old Brax in custom heat-sink. (kick myself daily for selling it)


Post it up,you know we all love pictures 

Sent from my SAMSUNG-SM-G925A using Tapatalk


----------



## PPI_GUY

So, who/what companies are making the best class A/B amps today? 
And why are they good?


----------



## thehatedguy

Take your pick...lots of great amps. Just depends on your esthetics, features, power, etc. Then you have main stream vs. boutique brands...lots of boutique brands out there.


----------



## wheelieking71

Victor_inox said:


> Post it up,you know we all love pictures
> 
> Sent from my SAMSUNG-SM-G925A using Tapatalk


The mentioned MMATS LM2125 that is currently rocking my den at home:



I really like it. Powerful, and transparent.

The BRAX I never should have sold:







That amp was as close as I have ever been to a "wire with gain", lots of gain!

And just for giggles, tuning up a couple ADCOM's that showed up out of tune, and sounding shall we say, like ****! LOL


----------



## Victor_inox

I can only imagine amount of aluminum wasted on that project but you right you should ***** slap yourself for selling it.


----------



## wheelieking71

Victor_inox said:


> I can only imagine amount of aluminum wasted on that project but you right you should ***** slap yourself for selling it.


I paid $225 for the chunk. Here it is before I started with the board sitting on it:


----------



## 1996blackmax

Littlejerryseinfeld said:


> The fact that some people choose the harder road should shed some light on the differences. I'd love to slam 600 watts under my front seat. However, I'm not willing to compromise sound to do it.


This reminds me of my Arc Audio amps. I had a 4150-XXK & a 1500-XXKv1 (the bigger a/b revised version) under the front seats of my last car. It was a tight fit, but I was able to mount those puppies under there. The 1500 was rated at 1000 watts. These were some of my favorite amps....good amount of power, never had any issues, and loved the look.


----------



## capea4

my friends picking on me, cause i keep changing amps expecting there to be a difference, only to get mad when i can't find one


----------



## 1996blackmax

Funny how much dislike there is towards class d. Have the people that are putting it down tried all different brands in the same car with all the same equipment right after each other?


----------



## WestCo

1996blackmax said:


> Funny how much dislike there is towards class d. Have the people that are putting it down tried all different brands in the same car with all the same equipment right after each other?


I test my amps at home with an old computer power supply.
Best way to test full range amps.


----------



## ca90ss

There's not a single person here no matter how special everyone thinks they are that can tell the class of an amp just by listening to it.


----------



## kyheng

TOOSTUBBORN2FAIL said:


> Jl hd's switch at 400,000.


That's higher that what I heard


----------



## Victor_inox

WestCo said:


> I test my amps at home with an old computer power supply.
> Best way to test full range amps.


 Typical ATX power supply only has 3 to 5A of current available on 12V rail, definitely NOT the best way to test your amplifiers.


----------



## WestCo

Victor_inox said:


> Typical ATX power supply only has 3 to 5A of current available on 12V rail, definitely NOT the best way to test your amplifiers.


*server PSU 80A on tap


----------



## Victor_inox

WestCo said:


> *server PSU 80A on tap


 server PSU- agreed, loud as hell but cleanest power available.


----------



## WestCo

Littlejerryseinfeld said:


> The point was, once again, any question raised to the A/B side can be asked of the D side.
> 
> We all know the truth though. Most people can't afford, and/or don't have the will to want to test a number of amps. They get on here, hear about what the current boner is, and buy that.


It's definitely isn't cheap that's for sure. But from a guy who has taken the time to test amps, it is definitely worth doing. 

It's not uncommon to find some D's beating A/b's.


----------



## Victor_inox

WestCo said:


> It's definitely isn't cheap that's for sure. But from a guy who has taken the time to test amps, it is definitely worth doing.
> 
> It's not uncommon to find some D's beating A/b's.


 And that will be more obvious in near future. 
Progress always wins.


----------



## thehatedguy

http://www.diymobileaudio.com/forum...amplification-can-sound-just-good-true-b.html


----------



## schmiddr2

So many people know everything. I'm impressed.  

I'd guess the only people learning are the people not arguing or trying to prove something.


----------



## gstokes

PPI_GUY said:


> I am a member of several FB-based old school car audio groups and the outright hatred for anything using class D topology is amazing!
> Now, I am as old school as they come. Started in car audio in 1987 ..


I gotcha beat by a few years..
Bought a Sanyo 8 track player in 1974 with triaxials in the package shelf and an stereo amplifier that i can't remember the name of to save my life..
It was German or the name was, i want to say it starts with M but i just can't be sure..
Joined the military in 1979 and when i came home in 1982 it was still there under the dash of my 68 Mustang along with a Steve Miller tape 
Times keeps on Slippin..


----------



## High Resolution Audio

PPI_GUY said:


> So, who/what companies are making the best class A/B amps today?
> And why are they good?



TRU Technology

The only company I know where it's still
made with pride in USA and have a standard 1 year warranty, extendable out two three.

Very Expensive !!!


----------



## High Resolution Audio

Milbert BaM Mobile Tube Amplifier

Not sure what class there are, but these may be worth a view.

Even more expensive!!! , but toted as the best sounding car amplifier.


----------



## ssclassa60

High Resolution Audio said:


> Milbert BaM Mobile Tube Amplifier
> 
> Not sure what class there are, but these may be worth a view.
> 
> Even more expensive!!! , but toted as the best sounding car amplifier.



It's a high bias AB. 5A idle is pretty high for 30x2


----------



## Victor_inox

High Resolution Audio said:


> Milbert BaM Mobile Tube Amplifier
> 
> Not sure what class there are, but these may be worth a view.
> 
> Even more expensive!!! , but toted as the best sounding car amplifier.


it was in 1994.


----------



## DDfusion

High Resolution Audio said:


> TRU Technology
> 
> The only company I know where it's still
> made with pride in USA and have a standard 1 year warranty, extendable out two three.
> 
> Very Expensive !!!


MMATS makes amps in the US


----------



## High Resolution Audio

Victor_inox said:


> it was in 1994.


In tone audio magazine 2006 it was quoted as "the best sounding car amplifier on the face of the earth"


----------



## Victor_inox

High Resolution Audio said:


> In tone audio magazine 2006 it was quoted as "the best sounding car amplifier on the face of the earth"


If you believe everything printed in magazines. 
It`s nice amplifier and sounds good, not best in the world good but nice.


----------



## cajunner

I'd like to believe Victor's KT88 monoblock pair could go toe to toe with the Milbert, up to the power limits of those tubes.


I also like to believe the HSS Fidelity, rides high in listener euphemisms indicative of superiority by audio standards...

and it's a given that I could allot some sort of special sauce to the class A circuits of solid state architecture, even to the point that a class D switching supply, supplies the class A non-switching outputs of a custom design, perhaps even the upcoming idea box Victor is tone testing in situ.

but having the where, with, all...

to obtain, submit to installation, protect from theft and give it a lot of uninterrupted free time...

obtain is the harder part, eh..


----------



## Victor_inox

cajunner said:


> I'd like to believe Victor's KT88 monoblock pair could go toe to toe with the Milbert, up to the power limits of those tubes.
> 
> 
> I also like to believe the HSS Fidelity, rides high in listener euphemisms indicative of superiority by audio standards...
> 
> and it's a given that I could allot some sort of special sauce to the class A circuits of solid state architecture, even to the point that a class D switching supply, supplies the class A non-switching outputs of a custom design, perhaps even the upcoming idea box Victor is tone testing in situ.
> 
> but having the where, with, all...
> 
> to obtain, submit to installation, protect from theft and give it a lot of uninterrupted free time...
> 
> obtain is the harder part, eh..


KT120/150 will overpower that BAM and on top of that it`s Single ended Class A not PP like Milbert.


----------



## PPI_GUY

High Resolution Audio said:


> TRU Technology
> 
> The only company I know where it's still
> made with pride in USA and have a standard 1 year warranty, extendable out two three.
> 
> Very Expensive !!!


I am a fan of Tru amplifiers. Not just because they are made in the US but, they seem to be built with care. I've owned a few of their Billet series and they are very impressive. Seems I read the H-1 Hammer is nearly 70% efficient? That seems amazing for a class AB amp. But, price is the restrictive factor for me.


----------



## ChrisB

ca90ss said:


> There's not a single person here no matter how special everyone thinks they are that can tell the class of an amp just by listening to it.


Yes, but they can't handle the truth. Didn't a couple of forum members put on blind listening tests where the majority of the participants couldn't point out which amplifier they were listening to with any degree of statistical significance? In other words, the results were no different than guessing heads or tails in a coin toss. 

I'd venture to guess that these same people touting that their beloved 20 year old relic sounds better than anything produced today wouldn't fare much better in the same test environment. :laugh:

EDIT: Here is a link to the test http://www.diymobileaudio.com/forum...-blind-tests-amplifiers-time-hear-myself.html


----------



## High Resolution Audio

Victor_inox said:


> If you believe everything printed in magazines.
> It`s nice amplifier and sounds good, not best in the world good but nice.


So what would you consider "the best" in your experience?


----------



## Victor_inox

High Resolution Audio said:


> So what would you consider "the best" in your experience?


there is no best amplifier for everything, different amplifiers best for different applications. what`s best for 105db horns is definitely far from it for 79db midbass.


----------



## Babs

High Resolution Audio said:


> TRU Technology
> 
> 
> 
> The only company I know where it's still
> 
> made with pride in USA and have a standard 1 year warranty, extendable out two three.
> 
> 
> 
> Very Expensive !!!



Yeah that's some serious "Krell" level stuff. I would love to see more of these types of companies. The difference in components verses typical made-for-mass-market stuff is why these amps will still be selling used for pretty good coin while other amps will be on bench for repairs or just trashed. 


Sent from iPhone using Tapatalk


----------



## wheelieking71

ChrisB said:


> Yes, but they can't handle the truth. Didn't a couple of forum members put on blind listening tests where the majority of the participants couldn't point out which amplifier they were listening to with any degree of statistical significance? In other words, the results were no different than guessing heads or tails in a coin toss.
> 
> I'd venture to guess that these same people touting that their beloved 20 year old relic sounds better than anything produced today wouldn't fare much better in the same test environment. :laugh:
> 
> EDIT: Here is a link to the test http://www.diymobileaudio.com/forum...-blind-tests-amplifiers-time-hear-myself.html


I am not writing this post to argue with your points.
But, I would like some help understanding something.
I did my own little (very un-scientific) test a couple years ago.
I found a track, where through my previously mentioned headphone rig, there are some subtle details in the recording that are hard to hear, but, there.
I think it was a 4-non Blondes tune, can't remember really.
The subtle details were: somebody in the background says "oh ****" or something to that effect. And, in another spot you can barely hear somebody catching their breath.
Now, I listened to this same track through a bunch of different amps, all else remained the same. Why was it, that I could not hear these details when listening through every amp?
If all amps sound the same, I should have heard the same thing every time. Well, I did not.

So, can somebody shed some light on WHY?

This took place in a totally quiet room, power was from an ASTRON RS70, same speakers, same source, same everything, except amps. All with different results.

I am not saying I can pick out when I am listening to a certain brand of amp.
But, I am saying, I know what I did, and didn't hear.


----------



## WestCo

wheelieking71 said:


> I am not writing this post to argue with your points.
> But, I would like some help understanding something.
> I did my own little (very un-scientific) test a couple years ago.
> I found a track, where through my previously mentioned headphone rig, there are some subtle details in the recording that are hard to hear, but, there.
> I think it was a 4-non Blondes tune, can't remember really.
> The subtle details were: somebody in the background says "oh ****" or something to that effect. And, in another spot you can barely hear somebody catching their breath.
> Now, I listened to this same track through a bunch of different amps, all else remained the same. Why was it, that I could not hear these details when listening through every amp?
> If all amps sound the same, I should have heard the same thing every time. Well, I did not.
> 
> So, can somebody shed some light on WHY?
> 
> This took place in a totally quiet room, power was from an ASTRON RS70, same speakers, same source, same everything, except amps. All with different results.
> 
> I am not saying I can pick out when I am listening to a certain brand of amp.
> But, I am saying, I know what I did, and didn't hear.


Amps have different levels of clarity and sonic characteristics. They aren't the same because they have different internals and different people engineered them from different boards. Amplifier class is more about power efficiency overall then anything else. I haven't found a class D that beats a great class a biased amp (that's not to say that they can't); but many class D's can beat new and old school A/B's on clarity. It all breaks down to the internals and the engineers who put them together. 

It's good that you compared them, you know which have better clarity and which don't.

It's not all about power and headroom or amp class; yes that's part of the difference but it's far from the whole picture.


----------



## WestCo

Also do some RTA on A B testing, you'll also see the response curve change at the same relative power.


----------



## thehatedguy

Audio Wave

High end of the high end




Babs said:


> Yeah that's some serious "Krell" level stuff. I would love to see more of these types of companies. The difference in components verses typical made-for-mass-market stuff is why these amps will still be selling used for pretty good coin while other amps will be on bench for repairs or just trashed.
> 
> 
> Sent from iPhone using Tapatalk


----------



## Guest

npdang said:


> *Pics of the subs:*
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> *Build Quality + Aesthetics:*
> 
> Personally, I think both of these subs are amazingly well built for the money. Both subs feature all the amenities you would expect from a high end sub such as heavy cast frames, foam surrounds, push terminals, and a rubber gasket.
> 
> The Atlas has a somewhat nicer, chrome back plate and 12 spoke basket, venting under the spider, and of course a dead giveaway for an xbl^2 motor... the large nearly 1" chrome top plate. The cone also appears to be made from treated paper/kevlar with a carbon fiber dustcap glued on top.
> 
> The Tc2+ has sewn in tinsel leads and Imho, a nicer looking aluminum cone. The 4 spoke basket and no venting under the spider gives it a somewhat more rugged, if not dated look.
> 
> *Nearfield(taken at 1" from the driver's cone) Frequency response:*
> 
> Green = TC2+
> Blue = Atlas 12" with second voice coil shorted (low qts configuration)
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> This was very interesting. Given the manufacturer published specs, I would have expected the Atlas to have a more extended top end as well as noticeably higher efficiency. It clearly doesn't, and plots almost identically to the Tc2+. I have no explanation for this, as the inductance for the Atlas 12" is given at .86mh as compared to the tc2+ measured rating of 4.8mh @ 1khz. Also, seeing as the tc2+ was measured at 85.1dbwm, I would expect the high/mid qts configurations of the Atlas 12" to have an efficiency that makes the driver almost unusable.
> 
> *Non-linear distorion performance:*
> 
> Nearfield(taken 1" from the cone) measurement, drive level 20V rms(~100watts into 4 ohm nominal load), swept sine wave 20-100hz.
> 
> TC2+
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Atlas 12"
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Again, another surprise. The Atlas 12" has very audible rub/buzz/tinsel lead noise. The TC2+ is nearly dead silent. This was shocking, given that the Koda 10" I had tested almost 6 months back was a dead silent performer as well.
> 
> Looking at the harmonic distortion plots, the Atlas 12" has better 3rd, 4th, and 5th order products, but obviously worse 2nd order performance above 25hz.
> 
> Given a drive level of 20Vrms(~100 watts into a 4 ohm nominal load), it was sufficient to move both subs nearly to xmax at 20-30hz. I find performance in this region to be more indicative of non-linear performance at high excursions. With that said, I would have given the nod to the Atlas 12" as the better performer, except for the fact that the mechanical noises this driver produced in free-air made it nearly unlistenable. The upper end performance of the tc2+ was also very good, and this sub generally shows better performance at higher frequencies and lower excursions.
> 
> Final words:
> 
> All in all, I'd say both subs are clearly among the better drivers I've tested in my time for this price range. Whichever sub is the winner would depend on your specific needs.
> 
> Having had both subs in my car for a period of a few months, in the same box, with the same settings I'd say they are nearly identical in sound quality. The tc2+ had a very slightly deeper, punchier sound and the Atlas 12" was a bit lighter. Hardly even noticeable unless you owned both for awhile and were really familiar with the sound of both subs.


I understand that Audiowave is very well made... Grant was connected woth Genesis at one point...


----------



## thehatedguy

Yeah, but I'm not understanding the quotes lol.

But you have brands like Audiowave from every country...Bewith, Phass,...etc


----------



## Guest

True


----------



## ChrisB

WestCo said:


> Amps have different levels of clarity and sonic characteristics. They aren't the same because they have different internals and different people engineered them from different boards. Amplifier class is more about power efficiency overall then anything else. I haven't found a class D that beats a great class a biased amp (that's not to say that they can't); but many class D's can beat new and old school A/B's on clarity. It all breaks down to the internals and the engineers who put them together.
> 
> It's good that you compared them, you know which have better clarity and which don't.
> 
> It's not all about power and headroom or amp class; yes that's part of the difference but it's far from the whole picture.


I once owned a class a biased amplifier that sounded better than anything else that I ever owned on mids and highs. It was a Lunar L2200. The problem with it was efficiency. I'm acquaintances with the individual who built that particular amplifier and he told me that it would draw all 140 amps to make 400 watts RMS. It's rather unfortunate, but when my job situation changed and I was forced into a compact commuter car, I had to get rid of the amplifier. 

Here is one of the few pics that I can find of it showing Kenny's sense of humor:


Edit: Here is another pic of it notating its size:


----------



## Victor_inox

Most likely it was drawing 140 A at any moment including idle.

Sent from my SAMSUNG-SM-G925A using Tapatalk


----------



## ChrisB

Victor_inox said:


> Most likely it was drawing 140 A at any moment including idle.
> 
> Sent from my SAMSUNG-SM-G925A using Tapatalk


Whenever I tested it in the house, I'd use my Iota DLS55 connected to a battery. Whenever I tuned with it in the Mustang, I did the same thing! 

The individual who ended up with my old amp used it to power a set of older Diamond Audio Hex components in a GMC extended cab with their passive crossovers. Even he commented on how it was the best sounding amplifier that he ever heard on his components!

But alas, this all goes back to my comment about car audio being a compromise, so pick your poison. On one hand, you've got huge, inefficient amplifiers that leave little room for cargo and require expensive alternators with banks of batteries. On the other hand, most multi-channel class d amplifiers take up little space and a simple battery upgrade is all that is needed to power them.


----------



## Guest

Lunar was nice equipment... alway was partial to the L2200.... big surf board


----------



## thehatedguy

Yeah, I wanted some of them too.


----------



## wheelieking71

Funny ChrisB, I am pretty sure that Lunar 60x2 in your pic was one of the amps in my little unofficial test I talked about (at least I think I bought that Lunar from you).
Coincidentally, it was one of the amps where I could not hear the details I was looking for.


----------



## ChrisB

wheelieking71 said:


> Funny ChrisB, I am pretty sure that Lunar 60x2 in your pic was one of the amps in my little unofficial test I talked about (at least I think I bought that Lunar from you).
> Coincidentally, it was one of the amps where I could not hear the details I was looking for.


The 60x2 was a totally different amp from the L2200 in that the 60x2 was not Class A biased.

Edit: I could have sworn that SublimeZ and Benny ended up with my L60x2s; locals ended up with my L1500s and my L2200; a forum member ended up with my L2125 and a family member ended up with my L2100.


----------



## Hillbilly SQ

Looking at the quote with the Atlas and tc2+, I remember testing the original H-Audio Soul and Ebony. Both had identical response curves (provided by manufacturer) but sounded completely different. The Ebony was a midbass monster for what it was while the Soul had better clarity. Only difference afaik was the cone material.


----------



## ChrisB

No complaints about full-range class d here:


----------



## BadSS

1996blackmax said:


> Funny how much dislike there is towards class d. Have the people that are putting it down tried all different brands in the same car with all the same equipment right after each other?


My initial experience with Class D was around 2007 or 2008 and it wasn’t a good one - pretty much turned me against the idea of me running one. It was noisy, thin, hollow, tinny, edgy, and had poor dynamics against comparably RATED AB amps - it was flat out weak and got “nasty” really quick as it started to clip. It pretty much turned me against all “Ds”, but I do not feel the same way now after a recent install of JL HD amps in a friend’s car. I wasn’t able to do a direct comparison in my car as I have been able to do with most all the other (15-20?) AB amps I’ve bought and installed for folks. However, after the install and jumping from his car to my car (similar all AB power and similar, high quality, speakers) I really couldn’t tell much if any difference. The noise floor was really low (near zero) and it sounded great. The only minor issue was there was a very slight thump on powering off – not all that noticeable, but there. 

This is a really poor way to “compare” as I know in a similar car to car comparison of the most distinctly different AB to AB amp compared within my own system,,, I couldn’t hear that distinction in their car. By me saying the JL HD sounded great and I couldn’t really tell a difference is not saying they sound as good as the AB amps I’m running. What I am saying is,,, there is no way I could have determined whether those HDs were AB or D topology by sitting in the car. Considering I could hear differences between most of the AB amps I tested, I’m sure there would be similar differences in comparing a bunch of D amps. Could I have heard a difference in the HDs directly compared to the AB amps in my car? My guess is I probably could have,,, but the differences probably would have been no different than those that I heard comparing AB to AB.

SO,,, here’s what I know to be true – the main difference in amps, regardless of topology is the noise floor, dynamics of similarly RATED amps, and how they sound at or “flickering” around clipping. Even when these three things are equally good, you still might hear some subtle differences in a direct comparison against your favored amp in your car (if you have top notch speakers) or on a bench with good studio monitors. However, you’re going to be hard pressed hearing any distinct differences once installed in another car. I can’t help but believe those that THINK they have an “issue” with Class D amps, probably haven’t given the better designed ones a chance. 

That said, I wouldn’t say I’m a convert; I have a number of my favored AB amps squirreled away and have no plans to get rid of them. However, I’m doing a frame on restoration of my old hot rod (street/strip car) and depending on where the ETs are, I’d have no problem pulling and selling off the heavy AB amps and running those HD amps in favor of weight savings for a few hundredths of a second (a 11.02-second car is a “11-second” car,,, not a 10.99-second, “10-second”, car – lol).


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## ppia600

I don't have much class D exposure, other than the mtx we sold at ccity, a few earthquake PHD amps, my friend's eclipse full range d amps and of course hearing full range d amps in random friend's vehicles and retailers. I can tell you it's very obvious my friend's vehicle that the eclipse is not A/B. His system compared to my previous ppi art amps all A/B was like comparing XM radio to a good CD. He doesn't seem to discern the SQ differences in our setups though. I believe even though specs can be quantified digitally with electronic tools, our hearing and resolution for perception is vastly different from individual to individual. You can tell me this or that guy swears by class d full range and he runs eleventy metric tons of class d equipment, but he and I may not percieve the signals the same way.

I also noticed that running my previous phD2 on sub duty always felt like it was lagging in time, like there was some type of delay. I tried many different slope combinations for the mids/highs and subs and phase changes but it always felt that way. The phd2 also seemed to lack the low end punch my other amps like the A600.2 and PC2350 did, just "sound"ed different. 

I'm running an adcom 5450 (purchased from Wheelieking a while back) and it seems very detailed and smooth, even compared to my art amps. It is currently running at 4ohm per channel, but will be at 2 with the new components. I also have a MMATS LM2125 I recently replaced all of the T03 and their corresponding emitter resistors in. The competition for sub duty will be between it and a NIB PHD3 I've had sitting in a box for a couple of years. I realize the mmats has nowhere near the power, but if it has that subtle sound difference I was referring to, the earthquake will be on ebay. 

I believe class D amps may some day outdo SQ, in our realm of audible perception, but for now I will stick with what sounds better to me. Power output for a given footprint is obviously better with non a/b amps, but I'm not going to cry over a slightly larger amp that draws a little more current. I'm not driving a hybrid and worrying about a few extra mpg, and my car makes more than enough wtq to compensate for the added weight. The alternator is also 140a so I'm also not worried about toasting it with the few amps I run. 

Looks like my LM, but without powdercoat. Also, would you be able to give some advice on adjusting the bias for the adcoms? I am replacing every capacitor in my 5450 and will likely add some braid to reinforce the power traces. It would probably be a good time to get it "tuned" up and get the best it can deliver. 



wheelieking71 said:


> The mentioned MMATS LM2125 that is currently rocking my den at home:
> 
> 
> 
> I really like it. Powerful, and transparent.
> 
> The BRAX I never should have sold:
> 
> 
> 
> 
> 
> 
> 
> That amp was as close as I have ever been to a "wire with gain", lots of gain!
> 
> And just for giggles, tuning up a couple ADCOM's that showed up out of tune, and sounding shall we say, like ****! LOL


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## Hillbilly SQ

I had the same experience with a/b vs d on subs. The a/b amps (especially my Mosconi's) just seemed to have more control over the sub. Also a better transient response. And no, it's not all in my head either. Sure I've heard some great sounding cars with fullrange d amps but that doesn't mean anything in the grand scheme of things. I'll stick with quality a/b amps since they aren't much bigger watt for watt than class d amps if the a/b amp has forced cooling like my One series amps.


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## ssclassa60

ppia600 said:


> I don't have much class D exposure, other than the mtx we sold at ccity, a few earthquake PHD amps, my friend's eclipse full range d amps and of course hearing full range d amps in random friend's vehicles and retailers. I can tell you it's very obvious my friend's vehicle that the eclipse is not A/B. His system compared to my previous ppi art amps all A/B was like comparing XM radio to a good CD. He doesn't seem to discern the SQ differences in our setups though. I believe even though specs can be quantified digitally with electronic tools, our hearing and resolution for perception is vastly different from individual to individual. You can tell me this or that guy swears by class d full range and he runs eleventy metric tons of class d equipment, but he and I may not percieve the signals the same way.
> 
> I also noticed that running my previous phD2 on sub duty always felt like it was lagging in time, like there was some type of delay. I tried many different slope combinations for the mids/highs and subs and phase changes but it always felt that way. The phd2 also seemed to lack the low end punch my other amps like the A600.2 and PC2350 did, just "sound"ed different.
> 
> I'm running an adcom 5450 (purchased from Wheelieking a while back) and it seems very detailed and smooth, even compared to my art amps. It is currently running at 4ohm per channel, but will be at 2 with the new components. I also have a MMATS LM2125 I recently replaced all of the T03 and their corresponding emitter resistors in. The competition for sub duty will be between it and a NIB PHD3 I've had sitting in a box for a couple of years. I realize the mmats has nowhere near the power, but if it has that subtle sound difference I was referring to, the earthquake will be on ebay.
> 
> I believe class D amps may some day outdo SQ, in our realm of audible perception, but for now I will stick with what sounds better to me. Power output for a given footprint is obviously better with non a/b amps, but I'm not going to cry over a slightly larger amp that draws a little more current. I'm not driving a hybrid and worrying about a few extra mpg, and my car makes more than enough wtq to compensate for the added weight. The alternator is also 140a so I'm also not worried about toasting it with the few amps I run.
> 
> Looks like my LM, but without powdercoat. Also, would you be able to give some advice on adjusting the bias for the adcoms? I am replacing every capacitor in my 5450 and will likely add some braid to reinforce the power traces. It would probably be a good time to get it "tuned" up and get the best it can deliver.



Adcoms have two pots per channel, bias and dc offset. I highly recommend replacing the dc offset pots to multi-turn pots. When wheelie says 'out of whack' he's pointing to dc offset. The stock pots are very sensitive and bad offset (ideal is 0mV, 25 is acceptable) causes distortion. Bias on a 5450 is around 4-5A at idle. I'm pretty sure the bias pots are the ones closest to the heatsink


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## davewpy

I just felt that class D amps should be designed with digital inputs.

With the current signal chain, the processor does the DAC function. The class D would require ADC input which can alter the signal.

I had previously experienced class D in my setup. Loved the imaging and focus, but could not compare in overall presentation with my current A/B setup even though my A/B amp did not have the same level of imaging that the class D presented.

Sent from my ONE A2005 using Tapatalk


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## gstokes

Class D has Two advantages, compact size and low/er current draw being the two, that's it..
For a low powered system like mine (75 x 4 & 500 x 1) a Class AB amp is fine because the charging system will support it and i have plenty of room, there was no excuse for me not to use Class AB..
For a while i was hooked on Full-range Class D but it just doesn't compare with Class AB for SQ, too much signal processing going on inside Class D..
Amps have come a long way and so has Class D but for me I'm stuck on Class AB, if it ain't broke don't fix it..


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## Victor_inox

gstokes said:


> Class D has Two advantages, compact size and low/er current draw being the two, that's it..
> For a low powered system like mine (75 x 4 & 500 x 1) a Class AB amp is fine because the charging system will support it and i have plenty of room, there was no excuse for me not to use Class AB..
> For a while i was hooked on Full-range Class D but it just doesn't compare with Class AB for SQ, too much signal processing going on inside Class D..
> Amps have come a long way and so has Class D but for me I'm stuck on Class AB, if it ain't broke don't fix it..


what signal processing goes inside of D class?


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## gstokes

Victor_inox said:


> what signal processing goes inside of D class?


Victor you know your stuff so i have to ask, is that a serious question ?


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## Victor_inox

It is because I doubt that you do.


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## gstokes

Victor_inox said:


> It is because I doubt that you do.


hmm, ok..


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## DDfusion

gstokes said:


> Class D has Two advantages, compact size and low/er current draw being the two, that's it..
> For a low powered system like mine (75 x 4 & 500 x 1) a Class AB amp is fine because the charging system will support it and i have plenty of room, there was no excuse for me not to use Class AB..
> For a while i was hooked on Full-range Class D but it just doesn't compare with Class AB for SQ, too much signal processing going on inside Class D..
> Amps have come a long way and so has Class D but for me I'm stuck on Class AB, if it ain't broke don't fix it..


You tried terrible cheap class D.


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## SkizeR

gstokes, please enlighten us unfortunate enough to not know what signal processing goes on inside of a class D amp..


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## jackies

ppia600 said:


> our hearing and resolution for perception is vastly different from individual to individual.


I think this is the most important fact. Just like our knowledge of stuff is different. Like, one person says too much digital processing in class D amps, the other says no there isn't, because there is none. Alright, one is more informed than the other, theoretically this can be corrected. But if one person hears something and the other doesn't, that's it, first person says this is better because he clearly hears it, the other person says it can't be, and is mad because he thinks his opponent is lying or intentionally trying to confuse him, while in fact, he simply doesn't hear it. And there's no way to prove it one way or the other.


Like, I spend years experimenting with my home theater setup, mount extra tweeters on the ceiling and such, trying to see if I can create a more realistic sound space, and then my wife says she's alright with watching movies on a television...


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## ppia600

Victor_inox said:


> what signal processing goes inside of D class?





SkizeR said:


> gstokes, please enlighten us unfortunate enough to not know what signal processing goes on inside of a class D amp..



From my understanding, the fact the original analog signal is transformed into digital pulses and then back into an analog signal by the output filters seems to imply class D amps process the signal (signal processing)... and in this example the signal is processed twice digitally and once with the low pass output filter. If converting an analog signal into digital and then manipulating in that realm before changing it back to analog isn't signal processing, please enlighten me as to what is. 

https://en.wikipedia.org/wiki/Class-D_amplifier


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## Victor_inox

here we go again.
Modulating a signal is not digitizing it. with a big stretch you might call it processing but only if you call linear amplification processing it as well. 
Why people calling everything digital these days?

D class was named because D was next letter in the alphabet.
Read up on amplifiers classes not just one but all of them.


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## ppia600

First, this is no "again" for me. Although I've finally decided to join this forum after much browsing, it is apparent there is a lot of nose up type behavior here and a lot less understanding of how many of us are trying to learn... and hence forth make statements asking for help or even make statements that can be construed as false to some. I don't need to "read up" on amplifier class types, thanks for assuming. 

How about instead of bickering and trying to pry something out of a member who makes a statement you perceive false, educate them. Poking and humiliating someone into not participating does nothing for this type of forum. Most of us are here to learn and sometimes even share, if the right questions are asked. 

It is apparent you believe, and are believed to be, a person very knowledgeable in the field of class d design and manufacture. I have read posts by you and it seems you may have some tricks up your sleeve, and should easily be able to educate us on the differences in class d design that can make or break their capabilities in the full range field. 

When someone states they don't prefer their audio signal to be processed by an amplifier, how is that difficult to understand? You and many of us know the signal is changed several times from the input to out in a class d amplifier, and even a person understanding the slightest bit about modulating a signal a few times has the right to decide whether or not they prefer it to a full analog path. Unless you can prove a comparably priced full range class d does not make a noticeable difference to everyone in sq without its input signal modified by some external dsp to help its sonics, I would believe a simpler analog path a better choice for all out sq. I could care less how many pros push class d products from the companies who sponsor them, so please don't go off on a tangent. 






Victor_inox said:


> here we go again.
> Modulating a signal is not digitizing it. with a big stretch you might call it processing but only if you call linear amplification processing it as well.
> Why people calling everything digital these days?
> 
> D class was named because D was next letter in the alphabet.
> Read up on amplifiers classes not just one but all of them.


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## Victor_inox

ppia600 said:


> First, this is no "again" for me. Although I've finally decided to join this forum after much browsing, it is apparent there is a lot of nose up type behavior here and a lot less understanding of how many of us are trying to learn... and hence forth make statements asking for help or even make statements that can be construed as false to some. I don't need to "read up" on amplifier class types, thanks for assuming.
> 
> How about instead of bickering and trying to pry something out of a member who makes a statement you perceive false, educate them. Poking and humiliating someone into not participating does nothing for this type of forum. Most of us are here to learn and sometimes even share, if the right questions are asked.
> 
> It is apparent you believe, and are believed to be, a person very knowledgeable in the field of class d design and manufacture. I have read posts by you and it seems you may have some tricks up your sleeve, and should easily be able to educate us on the differences in class d design that can make or break their capabilities in the full range field.
> 
> When someone states they don't prefer their audio signal to be processed by an amplifier, how is that difficult to understand? You and many of us know the signal is changed several times from the input to out in a class d amplifier, and even a person understanding the slightest bit about modulating a signal a few times has the right to decide whether or not they prefer it to a full analog path. Unless you can prove a comparably priced full range class d does not make a noticeable difference to everyone in sq without its input signal modified by some external dsp to help its sonics, I would believe a simpler analog path a better choice for all out sq. I could care less how many pros push class d products from the companies who sponsor them, so please don't go off on a tangent.


I haven`t quoted you therefore my response was directed to no one in particular.
You are new to all this 2000 times repeated discussion.
Processing is active action to change input signal.
modulation can`t be qualified as such. Plain and simple.
Ask direct question to receive direct answer.
I`m at luxury not having to prove anything to you nor anybody else.
As of today Class D not just capable not make noticeable difference to everyone in sq in comparison to AB but in some cases sounds more natural and linear that "linear amplifiers. and still evolving.


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## hurrication

ppia600 said:


> I believe even though specs can be quantified digitally with electronic tools, our hearing and resolution for perception is vastly different from individual to individual.


You hit the nail on the head with this one. Psychoacoustics pretty much rules the audio realm as an undetected yet undisputed dictator. All sorts of external cues are capable of changing one's perception of different audio signals even if they measure identically. Price, brand name, "passion", flashy build quality, and marketing are all factors that contribute to this. It's why companies like Wilson Audio exist. 

As far as I'm aware, nobody has passed Richard Clark's amplifier challenge yet, right?


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## quality_sound

hurrication said:


> You hit the nail on the head with this one. Psychoacoustics pretty much rules the audio realm as an undetected yet undisputed dictator. All sorts of external cues are capable of changing one's perception of different audio signals even if they measure identically. Price, brand name, "passion", flashy build quality, and marketing are all factors that contribute to this. It's why companies like Wilson Audio exist.
> 
> As far as I'm aware, nobody has passed Richard Clark's amplifier challenge yet, right?



If he'd clip those amps I bet a lot of people would. I think that's where most people are it being true with themselves and their true power needs. Even running a JL 900/5HD and a 600/4HD bridges wasn't enough for me and when I clipped, I hated it. I switched to mosconi AS100.4 and AS200.2 and was perfectly happy. Power was close to the same in both setups (except the midbasses which saw quite a bit less than with the HDs) but when I got into clipping the mosconis sounded better. If class D, G, H, whatever, clipped like AB amps, or I had the space/budget to run the power I really need, I'd run them and probably be happy with them. 


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## ppia600

Does the difference in damping factor between good class "d" and class "ab" amplifiers play a role in any of this?


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## ca90ss

ppia600 said:


> Does the difference in damping factor between good class "d" and class "ab" amplifiers play a role in any of this?


No.


.


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