# How does RIPS (JL Audio) work?



## lycan (Dec 20, 2009)

I'd like to start a DETAILED thread about RIPS. There seems to be a lot of confusing ... and/or _potentially_ confusing ... info out there, so i'd like to propose a SPECIFIC outline :

- Describe a speaker with an impedance that varies with frequency
- Describe an "interesting" test signal
- Describe ... in DETAIL ... how a more standard voltage source amplifier would drive it
- Inquire ... in DETAIL ... about how an amp with RIPS load regulation would drive it

I'll readily admit that i don't (yet) understand RIPS. The whole concept of the source (amplifier) regulating ... or attempting to regulate ... a load (speaker) doesn't make sense to me  That's why i want to learn 

Note : I don't want to discuss, or include, _supply regulation_ in an amplifier. That's a _separate_ topic. However, if there are _other_ types of "load regulation", they're fair game  It's not my intention to "pick on" JL Audio, at all.

*THE SPEAKER*

The speaker I have in mind is simply this :

50Hz -> 100Hz, impedance = 8 ohms
100Hz -> 200Hz, impedance = 4 ohms
200Hz -> 400Hz, impedance = 2 ohms

My marketing department  calls this speaker "nominally 4 ohms" 

My engineering department  tells me that, like most speakers, the SPL output of this speaker will be "pretty flat" (constant amplitude with frequency) if the voltage applied to it is "flat" (constant amplitude with frequency).

*First observation:* This speaker (like most) is NOT "expecting" constant _power_ across all frequencies, in order to generate constant SPL output across all frequencies. How do I know this?


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## lycan (Dec 20, 2009)

*INTERESTING TEST SIGNAL*

OK ... so there's really _two_ interesting test signals:

1. *Test signal #1:* This test signal is a _slow_ frequency sweep, from 50Hz to 400Hz, constant amplitude. It's applied as soon as the system is turned-on.

2. *Test signal #2:* This test signal is a _slow_ frequency sweep, from 400Hz to 50Hz, constant amplitude. Not really all that different, eh?  It will also be applied (in a separate test, of course) as soon as the system is turned-on.


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## tintbox (Oct 25, 2008)

Subscribed.


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## lycan (Dec 20, 2009)

*STANDARD VOLTAGE-SOURCE AMPLIFIER*

I'm going to pick something like a McIntosh 100W/4-ohm amp. No, not because of my well-known love affair with the brand :blush: but because the specs & schematics are readily available  so i know how this thing works.

Full specs of interest :

* 100 watts into 4 ohms, with less than ~0.1% distortion
* 200 watts into 2 ohms, with less than ~0.1% distortion (specified)
* 50 watts into 8 ohms, with less than ~0.1% distortion (deduced)
* rail voltage : +/- 30 volts (from service manual, consistent with 100W/4-ohm)

(I'm going to "round" a little to 30 volts, rails and signal peaks, and ignore the couple volts of headroom needed to keep output transistors active)

1. *Detailed operation with Test Signal #1* : full-scale signal sweep starting at 50Hz, slowly progressing up to 400hz

a. *Low-region* : 50Hz -> 100Hz (speaker impedance is 8 ohms)

* voltage amplitude is 30 volts
* power to speaker is 50 watts
* distortion is low ~0.1%

b. *mid-region* : 100Hz -> 200Hz (speaker impedance is 4 ohms)

* voltage amplitude is 30 volts
* power to speaker is 100 watts
* distortion is low ~0.1%

c. *high-region* : 200Hz -> 400Hz (speaker impedance is 2 ohms)

* voltage amplitude is 30 volts
* power to speaker is 200 watts
* distortion is low ~0.1%

Other notes :
1. SPL output from speaker remains ~constant through all 3 regions.
2. Gain of amplifier was set so that signal sweep achieved full-scale at amplifier output (30 volts). Gain was, naturally, unchanged throughout test.

Next up, i'll describe what happens with *Test Signal #2* with this amplifier ... although it will be pretty boring (redundant).


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## lycan (Dec 20, 2009)

2. *Detailed operation with Test Signal #2* : full-scale signal sweep starting at 400Hz, slowly descending down to 50Hz

a. *high-region* : 400Hz -> 200Hz (speaker impedance is 2 ohms)

* voltage amplitude is 30 volts
* power to speaker is 200 watts
* distortion is low ~0.1%

b. *mid-region* : 200Hz -> 100Hz (speaker impedance is 4 ohms)

* voltage amplitude is 30 volts
* power to speaker is 100 watts
* distortion is low ~0.1%

c. *low-region* : 100Hz -> 50Hz (speaker impedance is 8 ohms)

* voltage amplitude is 30 volts
* power to speaker is 50 watts
* distortion is low ~0.1%

Other notes :
1. SPL output from speaker remains ~constant through all 3 regions.
2. Gain of amplifier was set so that signal sweep achieved full-scale at amplifier output (30 volts). Gain was, naturally, unchanged throughout test.


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## lycan (Dec 20, 2009)

*What i'm looking for* :

Very simple. An equally detailed description of how a JL Audio amp (with RIPS), rated at :

100W into 4 ohms
100W into 2 ohms

will operate under these same conditions  Or ... any other amp with "load regulation".

I'll take a guess later, if nobody offers anything substantive ...


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## Thoraudio (Aug 9, 2005)

For what it's worth, here is an old Carsound review of a 300/4, complete with some charts and graphs.


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## rc10mike (Mar 27, 2008)

I thought all RIPS did was sense the initial load when powered up, then it "adjusts" and functions as a normal amp...


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## DS-21 (Apr 16, 2005)

There's also this review.

"When the total output power exceeds 315 watts the supply drops to the next voltage lower level. If it exceeds 370 watts, the supply drops the voltage again to match the load."

The only other thing I have to offer is subjective impressions. When I originally swapped my 300/4 for a Planet Audio BB175.4BB, I experienced no increased output capability. (For the record, the 300/4 was rated at 75x4/4Ω, a different BB175.4B benched out at 140x4/4Ωh if memory serves. Drivers didn't change.)

My normal experience is, especially when a system is a bit underpowered to begin with, doubling rated power is a noticeable change.

Based on that, I would say that one won't likely run into any sonic differences until/unless one pushes one or both of the amps to their limits.


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## lycan (Dec 20, 2009)

DS-21 said:


> There's also this review.
> 
> "When the total output power exceeds 315 watts the supply drops to the next voltage lower level. If it exceeds 370 watts, the supply drops the voltage again to match the load."
> 
> ...


that's some good general info, but i don't get the first quote 

The way Manville describes it, RIPS sets the rail voltage "early" after turn-on ... and it never changes (until power is cycled). So how does it know where to set the rail voltage?

Hence my sweep signals 

In general, i want to :

A. Understand the rail-setting technique better
B. Understand the power limits _after_ the rail voltage is set ... as speaker impedance varies, for example 

*For instance : can a RIPS amp deliver 200 watts into 2 ohms ... even though it is specified at 100 watts into 4 ohms, 100 watts into 2 ohms ... if the speaker impedance demands it, several minutes after turn-on? If so, at what distortion level? If it really *is* happy delivering twice the power into half the "rated" impedance ... then what's the point of RIPS?*

Anyway, it will help me a lot if i can get detailed answers to my experiment


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## Niebur3 (Jul 11, 2008)

Very Interested....subscribed! BTW, Jeff, did you get my email I sent to your personal email address? Just want to make sure you received it.


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## lycan (Dec 20, 2009)

Niebur3 said:


> Very Interested....subscribed! BTW, Jeff, did you get my email I sent to your personal email address? Just want to make sure you received it.


yes i got it ... don't know if you're ready yet, young jedi


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## Niebur3 (Jul 11, 2008)

lycan said:


> yes i got it ... don't know if you're ready yet, young jedi


But Master Yoda, I have 2 other Jedi Masters (Mace Windu and Obi-wan) as partners fighting the dark side!


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## squeak9798 (Apr 20, 2005)

lycan said:


> that's some good general info, but i don't get the first quote
> 
> The way Manville describes it, RIPS sets the rail voltage "early" after turn-on ... and it never changes (until power is cycled). So how does it know where to set the rail voltage?
> 
> ...


Not sure if this helps at all.....

"The decision the slash amp makes to switch rail voltages is not based on instantaneous measurements, so it won't be triggered by sudden reactive events... the mechanism involves a longer term PS current measurement which has been tweaked to be a very accurate indicator of actual nominal impedance......

If you were to "jam" a 300/2 in its lowest impedance mode... it would only make around 75-80 watts per channel at 4 ohms, but it would look pretty flat on a PowerCube chart. I don't find that better than making 150 watts per channel at 4 ohms nominal. If you were to "jam" it in its highest impedance mode (rail voltage) it would be unreliable at lower impedances."

Any other amps that use the R.I.P.S System - Page 11 - CARSOUND.COM Forum


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## rommelrommel (Apr 11, 2007)

I believe that RIPS uses the highest rail until impedance drops below a set level. Once it goes down a rail (or two) it doesn't go back up, until power gets cycled.


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## Niebur3 (Jul 11, 2008)

This is from that same thread squeak referenced:

RIPS has no problems at all with reactive loads... here's data from a review by A2000 published in CarSound

JL Audio 500/1: 

http://www.carsound.com/review_archi...s/jl_5001.html

Output Power (Resistive) (4 ohms @ 60 Hz to 1% THD+N): 605 watts @ 14 volts; 601 watts @ 12.8 volts; 591 watts @ 10.5 volts
Output Power (Resistive) (2 ohms @ 60 Hz to 1% THD+N): 620 watts @ 14 volts; 604 watts @ 12.8 volts; 598 watts @ 10.5 volts
Output Power (Reactive) (4-ohm IHF Load @ 60 Hz to 1% THD+N): 639 watts
Output Power (Reactive) (2-ohm IHF Load @ 60 Hz to 1% THD+N): 733 watts

JL Audio 300/4

http://www.carsound.com/review_archi...s/jl_3004.html

Output Power (resistive) minimum output 20 Hz to 20 kHz @ 1%THD+N, all channels driven into 4 ohms: 97 watts x4 @ 14 volts, 90 watts x 4 @ 12.8 volts
Output Power (resistive) minimum output 20 Hz to 20 kHz @ 1%THD+N, all channels driven into 2 ohms: 90 watts x 4 @ 14 volts, 88 watts x 4 @ 12.8 volts
Output Power (4-ohm IHF Reactive Load @ 60 Hz to 1% THD+N): 232 watts x 2

Best regards,

Manville Smith
JL Audio, Inc.


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## Oliver (Jun 25, 2007)

... and of course everyone wants to drive only some channels into 4 ohms and some into 2 ohms at the same time.


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## lycan (Dec 20, 2009)

Niebur3 said:


> This is from that same thread squeak referenced:
> 
> RIPS has no problems at all with reactive loads... here's data from a review by A2000 published in CarSound
> 
> ...


this doesn't help ... in fact, this is the source of my confusion 

re-read this thread _carefully_. The same power (essentially) delivered to a varying impedance is _confusing_. Speakers don't want it. *Look back a few posts to see how the standard voltage-source amp behaved, when presented with a speaker whose impedance varied with frequency.*

The only thing that will clarify this for me, is my experiment carried-out with a RIPS amp (doesn't have to be on a bench, it can be in this thread ... with someone who really knows how the damn thing works).

is there an issued patent?


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## Niebur3 (Jul 11, 2008)

lycan said:


> is there an issued patent?


In the same thread:

Actually...

Bruce Macmillan was the lead engineer at PPI in the late eighties/early 90's. He designed all the "Art" series amps as well as the 2350DM. The 2350DM had simpler version of the RIPS system with two "gears" so it could be optimized for 2 ohm or 4 ohm per channel operation.

Fast forward to 1999... Bruce was hired by JL Audio to design the JL Audio amplifiers. He took the 2350DM's power supply concept to a higher level with three "gears" of optimization (the 1000/1 actually has four). So, in essence, the PPI2350DM and the JL "slash" amps came from the same brain.

JL Audio does not have a patent on the RIPS system (it had been done before, so you can't patent it). The patented technologies in the slash amps (and the e-series) have to do with the output sections, not the power supplies.

I'm not sure exactly what is going on in the PG products, but it appears to be a different approach towards the same basic goal.

Best regards,

Manville Smith
JL Audio, Inc.


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## matt1212 (Jan 14, 2010)

As the owner of 4 Slashv2 amps, officially subscribed. Lets hope we can get manville in here with some good insight


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## msmith (Nov 27, 2007)

Okay... let's look at the big picture, which I think will clear up most of the confusion.

RIPS has two parts... supply regulation and load impedance optimization. Supply regulation is what allows the amp to maintain rated power even when supply voltage drops to 12V or below. It doesn't let the rails sag when the voltage dips. 

Load impedance optimization is what everyone seems to be confused about, so let's discuss it more specifically.

If you ask an engineer to design a "500 Watt amplifier", you are likely to get a few questions back, but the first one will likely be "at what impedance load would you like the 500W to occur". The answer to this question will determine several design parameters of the amplifier and power supply circuits. 

If the answer is "1 ohm", then the amplifier must be designed as a "high-current" design, which means it will make its 500W at 1 ohm (meaning a rail voltage of 22.3 V and 22.3A of current capability). 

If the answer is “I want 500W at 4 ohms.”, then the design needs to have a higher rail voltage and less current capability (44.7V and 11.2 A). In either case, we’re designing a “500W amplifier”, but certain aspects of the power supply and other parts of the circuit need to be adjusted depending on the load and whether more voltage or more current is required to make 500W.

The high-current version might be a little more expensive to make, but the two amps (1 ohm or 4 ohm) are going to be close in cost and similar in design.

Now, inevitably, a ‘creative thinker’ comes along and wonders what happens when we take the amp designed to make 500W at 4 ohms and connect it to a 1 ohm load! Well, since it has 44.7V rails and is not a sentient being, this amp will try to deliver 2000W into a 1 ohm load, which requires 44.7A of current… and here we have a problem as the designer never intended it to be able to do this and the amplifier gets really pissed off and hot and either shuts down to protect itself, blows a fuse or catches on fire.

Now, most car amplifiers are designed to produce optimum (highest stable) design power at 2 ohms, so if we follow that approach for our “500W” amplifier, we would specify a rail voltage of 31.6V with 15.8 A of current capability. If we try to load the amplifier down to 1 ohm, it will run out of current, so we put in a protection circuit to shut it down or mute if someone tries to do that. If you put a 4 ohm load on the amp, the 31.6V rails translate to 250W and the current demand goes down to 7.9 Amps. At 4 ohms, the amp is cooler than the other side of the pillow and cruising well below its capabilities, and we only get half the power output that it is truly capable of.

Now, the marketing guy says… “Perfect! We will call this a 250W amplifier and then tell people they can DOUBLE THEIR POWER to 500W at 2 ohms… woohooo, it’s like a 2 for 1 sale!” The engineer might say… “Well, at 4 ohms, you’re really not getting the power the amp is designed to produce, but go ahead and rate the amp any way you want, you silly marketing twit.” << and this is how we’ve all become accustomed to understanding amplifiers and how they behave into different loads. We’re all told that power increases at lower impedances, but it’s actually more correct to say that power output decreases at higher impedances (taking the optimal design power as the baseline figure).

Okay, so hopefully that explains the basics of an amplifier with a singular rail voltage.

Now, somebody who thinks a little deeper comes along and says. “You know, it sure sucks that we have to load the amp down to get all the power that was designed into it. It would be great if we could tell the amp what the load is so that it can always make its full power.” A well-meaning engineer overhears this reasonable request, and says… “We can do that! We’ll simply put a switch marked “2 ohms or 4 ohms” and let the user select the appropriate position for his application. The switch will lower the rail voltage at the 2 ohm position so the amp is still 500W and doesn’t catch on fire. (Soundstream and Sony did this a while back).

Seems like a really smart, reasonable solution to give the customer the 500W he paid for every time, right? Only one problem: the amp gets louder when you put it in the 4 ohm switch position and connect it to a 2 ohm load, and someone posts that on DIYMA and everybody starts to do it, and pretty soon everyone is complaining that the amp is a P.O.S. because it catches on fire.

So, then another engineer comes along and says “We must make this function automatic and transparent to the user.” and the ancestor of RIPS is created. (PPI 2350DM in the early 90’s). This amplifier had two settings (2 ohm and 4 ohm) that it selected automatically by detecting the load’s impedance through a current measurement on the output of the power supply at clipping. This clever piece of engineering cost some dollars to implement and took some time to tweak and perfect, but in essence gave this amp an automatic version of the “2 ohm or 4 ohm” switch, so that people couldn’t select the wrong position and burn the amp up. So, this unique amp was rated to produce 350W x 2 @ 4 ohms or 2 ohms. It should be noted, that during operation the amp will never switch back and forth from the “2 ohm” to the “4 ohm” rail voltage… it picks one and stays there, behaving just like a regular old fixed rail voltage source amplifier.

Fast forward a few years, and a few company upheavals later, and the engineer who designed the 2350DM ends up working for JL Audio and is tasked with designing an all-new line of amplifiers (the original Slash series). His name is Bruce Macmillan and he really wanted to take the lessons learned in the 2350DM and take them to a higher level of refinement across an entire line of products. We gave him the freedom to do so and he came up with the technology that we call RIPS. This is a more sophisticated version of the “2 ohm or 4 ohm” approach, actually involving 3 or 4 “switch positions”, depending on the model. The detection of the load is also far more sophisticated than the original 2350DM design. 

I really can’t go into any great detail about its operating parameters, because it’s proprietary stuff, but I’ll give enough info to convey how it works in general terms.

A)	Amp turns on and wakes up in the 4 ohm setting (highest rail voltage)

B)	If the user never turns it up loud and never clips the amp, it will stay in the high-voltage setting (yes, with craploads of headroom if you’re running a low impedance).

C)	When the user cranks it up gets near clipping, a circuit in the power supply control circuitry monitors current output and, based on that, makes a very intelligent decision about the connected load, and either leaves the rail voltage at maximum or reduces it to one of two or three lower positions (depending on the model). This position is now held (latched) until the amplifier is turned off.

Now, it should be noted that the amp makes an assessment based on real world current demands at clipping and the circuit has been tweaked to allow the amplifier to deliver the most rail voltage that is safe into a given load. The amp doesn’t “know” the specs of the speakers, it measures its output to determine what it can safely give and gives you that. In many cases, this results in significantly more “real-world” power than with amps that have fixed, singular rail voltages. What you think might be a “2 ohm load” based on speaker specs may actually never dip below 3 ohms, and the RIPS system will recognize that and give you full power at the higher real-world impedance. The circuit logic is also sophisticated enough not to be fooled by reactive or transient signals. There is also no gain change when the “switching” occurs. The output voltage remains stable. 

It should also be noted that if you load a RIPS-equipped amp down to 1.5 ohms and then disconnect the 1.5 ohm load (without turning the amp off and on again) and replace it with a 4 ohm load, the amp will remain in the low voltage position and produce reduced power at 4 ohms (just like a normal amplifier). Once it latches down, it stays there until the next power cycle.

The last point I will make in this rather long-winded response, is that RIPS is by no means a dynamic circuit. The rail voltage will not fluctuate once the amp has determined the optimum voltage. It behaves like a simple voltage source amplifier with the right voltage to make the amplifier’s rated power into that load. 

Hope that answers the questions and doesn’t raise too many more… but feel free to ask.

Best regards,

Manville Smith
JL Audio, Inc.


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## Thoraudio (Aug 9, 2005)

So, if I cruise along all week, a nominal volumes, but crank it up at the show on the weekend, do I need two eq curves?


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## msmith (Nov 27, 2007)

Thoraudio said:


> So, if I cruise along all week, a nominal volumes, but crank it up at the show on the weekend, do I need two eq curves?


Why would you need two EQ curves? The gain never changes... the only thing that happens when you don't crank it up is that the rail voltage is sitting at its highest setting. 

Rail voltage is not signal... rail voltage is potential unclipped signal level.


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## lycan (Dec 20, 2009)

Thanks for the long response manville ... but sadly it doesn't help me 

Let's say the amp turns on and "recognizes" a 4-ohm load, and adjusts the power rails accordingly.

But it's not until several seconds (or minutes) later, that volume is cranked close to clipping AND some frequencies are played where the speaker's actual impedance is much closer to 2-ohms.

As i understand it, the amp now has a "choice" :

1. Ratchet the rail voltage down, where it will stay until power is cycled.

2. DRIVE the 2-ohm impedance (that manifests at certain frequencies).

IF the amp happens to pick Choice #2, can it happily (meaning, low distortion) drive the 2 ohm load at twice the power that it drives a 4 ohm load?

*In other words, can a RIPS amp rated at 100W/4-ohm and 100W/2-ohm *happily* drive a 2 ohm load to 200 watts ... under circumstances (as described) where the rails are latched in "4-ohm" position, but the speaker's impedance (for some freqs) drops closer to 2 ohms?*


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## t3sn4f2 (Jan 3, 2007)

Can overdriving the amp confuse RIPS into latching down to a lower rail voltage?


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## kvndoom (Nov 13, 2009)

That was a very informative explanation, thanks Manville!


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## msmith (Nov 27, 2007)

lycan said:


> The speaker I have in mind is simply this :
> 
> 50Hz -> 100Hz, impedance = 8 ohms
> 100Hz -> 200Hz, impedance = 4 ohms
> ...


Your marketing department should not be specifying nominal impedances. That should properly be called a 2 ohm nominal load. 



> My engineering department  tells me that, like most speakers, the SPL output of this speaker will be "pretty flat" (constant amplitude with frequency) if the voltage applied to it is "flat" (constant amplitude with frequency).
> 
> *First observation:* This speaker (like most) is NOT "expecting" constant _power_ across all frequencies, in order to generate constant SPL output across all frequencies. How do I know this?


Based on your description of the load, the amp might end up in the 2 ohm or 3 ohm setting for this load. 

But, regardless of which "gear" RIPS ultimately selects (1.5 ohm, 2 ohm, 3 ohm or 4 ohm), the amp will behave like a typical voltage source amplifier with a fixed rail voltage. It is not a "constant power across all frequencies, regardless of impedance" device... that would be very strange, indeed.


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## msmith (Nov 27, 2007)

t3sn4f2 said:


> Can overdriving the amp confuse RIPS into latching down to a lower rail voltage?


No, not really. 

Overheating the amp will cause the protection circuitry to roll back rail voltage (until it cools again). This is the "Rollback Protection" circuit.


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## lycan (Dec 20, 2009)

msmith said:


> Your marketing department should not be specifying nominal impedances. That should properly be called a 2 ohm nominal load.


You _know_ that's not true.

I can show you plenty of speakers "marketed" as 4 ohms, with an impedance value ... at _some_ frequencies ... *lower* than 4ohms.

Same is true for "8 ohm" speakers ... many will have an impedance value *less" than 8 ohms, over _some_ frequency range.


> Based on your description of the load, the amp might end up in the 2 ohm or 3 ohm setting for this load.
> 
> But, regardless of which "gear" RIPS ultimately selects (1.5 ohm, 2 ohm, 3 ohm or 4 ohm), the amp will behave like a typical voltage source amplifier with a fixed rail voltage. It is not a "constant power across all frequencies, regardless of impedance" device... that would be very strange, indeed.


As succinct as possible :

*Again ... let's say a RIPS amp rated at 100W/4-ohm and 100W/2-ohm is operating at the 4-ohm rail setting. If, for some range of frequencies, the speaker's impedance actually drops close to 2 ohms ... can the RIPS amp drive it *happily* .... at close to twice the power, with low distortion, over that frequency range?

Or, must the amp necessarily latch to the lower rail setting (from which it will not recover) if it encounters the described "impedance dip" ... for some frequencies?*


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## msmith (Nov 27, 2007)

lycan said:


> Thanks for the long response manville ... but sadly it doesn't help me
> 
> Let's say the amp turns on and "recognizes" a 4-ohm load, and adjusts the power rails accordingly.


Actually, it doesn't need to recognize a 4 ohm load... that is its default rail voltage and will remain there for any load 4 ohms or higher.



> But it's not until several seconds (or minutes) later, that volume is cranked close to clipping AND some frequencies are played where the speaker's actual impedance is much closer to 2-ohms.
> 
> As i understand it, the amp now has a "choice" :
> 
> ...


Yes, it can, to some extent... like any well-designed voltage source amp, and as long as you don't exceed the current limits that are set into the RIPS system... This starts to get into the area I can't really talk about in too much detail. I'll just say that we design it so that you can clip the daylights out of the amp at 4 ohms (or any other setting) without it ratcheting down, so when played rationally there is plenty of effective headroom.

*



In other words, can a RIPS amp rated at 100W/4-ohm and 100W/2-ohm *happily* drive a 2 ohm load to 200 watts ... under circumstances (as described) where the rails are latched in "4-ohm" position, but the speaker's impedance (for some freqs) drops closer to 2 ohms?

Click to expand...

*Not only can it, but it often does.

You ask too many questions. :laugh:


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## lycan (Dec 20, 2009)

and if you think my "described" variations in the impedance of a _single driver_ are "too extreme" ... we haven't even _begun_ to discuss possible impedance variations (over frequency) in a multi-driver loudspeaker, with passive crossovers!


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## msmith (Nov 27, 2007)

lycan said:


> and if you think my "described" variations in the impedance of a _single driver_ are "too extreme" ... we haven't even _begun_ to discuss possible impedance variations (over frequency) in a multi-driver loudspeaker, with passive crossovers!


Well, I've seen some pretty ridiculous multi-way passive systems with high price tags that claim a 4 ohm impedance and dip below 1 ohm... so I know what you're talking about there. That's just bad design in my opinion, but it's just my opinion.


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## msmith (Nov 27, 2007)

lycan said:


> You _know_ that's not true.
> 
> I can show you plenty of speakers "marketed" as 4 ohms, with an impedance value ... at _some_ frequencies ... *lower* than 4ohms.
> 
> Same is true for "8 ohm" speakers ... many will have an impedance value *less" than 8 ohms, over _some_ frequency range.


Just proves my point that marketing people shouldn't decide the specs. 

You should have seen the debates around here when Proni designed a weird 3 ohm impedance subwoofer... sales wanted to just call it a 4 ohm... Proni won.


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## lycan (Dec 20, 2009)

The _fundamental problem_ i have with *any* amplifier that attempts "load regulation" ... even in a crude form, even with rail adjustment only ... is that the load (speaker) doesn't want its _power_ regulated. The load wants its _voltage_ regulated (what this means is that the load will create an SPL output that's reasonably independent of frequency, if the applied voltage is reasonably independent of frequency. That's what i mean by "what the load wants").

The ideal scenario ... which admittedly, NO amplifier on earth achieves ... is a constant voltage (vs freq) drive of the loudspeaker. The current, and power, will vary all over the place, depending on speaker's impedance. That's our world ... our ideal target. Certainly impractical.

Now I get what you are saying ... once the rail is latched, the amplifier behaves like a voltage source amp. BUT, the rail-latching algorithm is doing a crude job of power regulation ... as the marketing specs indicate. It keeps the power limited, as measured impedance drops.

Again, i'm not picking on JL. I'm seeing more & more amplifiers marketed with the SAME power at 2 ohms, as 4 ohms. It's just plain stupid ... it may help keep the amplifier safer, and minimize field returns ... but it's not what the load wants


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## lycan (Dec 20, 2009)

msmith said:


> Well, I've seen some pretty ridiculous multi-way passive systems with high price tags that claim a 4 ohm impedance and dip below 1 ohm... so I know what you're talking about there. That's just bad design in my opinion, but it's just my opinion.


i agree, that's bad design. So ... what's an acceptable "range"? hell if i know.

BUT ... zobels (and other impedance compensation) should not be too quickly dismissed, especially in a world where more & more amps are featuring "load regulation."

That's just my opinion


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## msmith (Nov 27, 2007)

What is the load "not getting" with a RIPS amplifier that it would get without RIPS?

For example, a non-RIPS version of the HD600/4 would produce 75Wx4 @ 4 ohms and 150Wx4 @ 2 ohms.

How is that better than the version that makes 150Wx4 at 4 ohms... especially when running components (which are typically 4 ohms)?


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## lycan (Dec 20, 2009)

msmith said:


> What is the load "not getting" with a RIPS amplifier that it would get without RIPS?


Let's assume a "so-called" 4-ohm speaker with an impedance that drops, over some range, to 2.5 ohms. Not un-common, i think.

Let's use that McIntosh amp : 100 watts into 4 ohms, 200 watts into 2 ohms, all with low distortion. This amp can happily drive that load, with low distortion, to 30 volts across the whole frequency range. That will equate to 100 watts for freqs where the impedance is 4 ohms, and 160 watts for freqs where the impedance is 2.5 ohms. Agreed?

Now, lets ask if a RIPS amp rated at 100W/4-ohm, 100W/2-ohm can do the same thing. Certainly, if the impedance were a "constant" 4-ohms, the answer would be yes. But what will the RIPS amp do, when it encounters that 2.5 ohm imepdance dip?

A. Ratch the rail voltage BELOW 30 volts, thereby prohibiting the amp from ever being able to supply 30V to this load.

B. NOT ratch the rail voltage BELOW 30 volts, thereby trying hard to deliver the 160 watts required. But ... at what distortion level? How hot, how much stress on the output stage, trying to deliver WELL OVER the 100 watt power?

Now ... i suppose we could just say : well, the load is really NOT 4 ohms, it's 2.5 ohms ... because the world needs to always be specifying minimum impedance. Therefore, what you need is a _different_ RIPS amp, one with higher rated power, one specified at 160 watts over a wide impedance range. Then it will certainly behave just like the 100W McIntosh amp, for this load.

The problem is, in my view, we live in a world where impedances vary with frequency. Trying to specify constant power over a wide imepedance range is not appropriate, given the reactive nature of our loads.


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## lycan (Dec 20, 2009)

Would it be fair to say the following :

*If i want a fair, valid comparison between a RIPS amp and a non-RIPS amp, i really must compare specified power levels at the MINIMUM value of loudspeaker impedance ... rather than the "marketed" value, or "nominal" value?*

I think the answer is YES 

Not that there's anything wrong with this. Perhaps, in many cases, the impedance levels won't be all that different ... in which case, it's a non-issue.

I just think this statement (bolded, above) is educational to the typical hobbyist.


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## msmith (Nov 27, 2007)

> Now I get what you are saying ... once the rail is latched, the amplifier behaves like a voltage source amp. BUT, the rail-latching algorithm is doing a crude job of power regulation ... as the marketing specs indicate. It keeps the power limited, as measured impedance drops.


Not sure why you think it's crude or undesirable... it's just optimizing the voltage/current ratio to best suit the applied load and allowing the full power capability of the amp to be deployed into that load.

For example, if you're running a "2 ohm" subwoofer driver in a sealed box, your minimum impedance will generally be closer to 4 ohms. RIPS will make sure you get twice the power in that situation compared to the same amp without RIPS. To the user, that's a "2 ohm subwoofer system", but it's really not. In car audio, we need to deploy a wide range of speaker systems and all kinds of subwoofer systems in all kinds of enclosures that have different impedance characteristics.

Now, if the amp is for a known (or closed system), like our Fathom powered subwoofers for home use, RIPS is unnecessary. We know the impedance of that system really well, so we design the amp to suit that one specific application. 

Not all amps that have "load regulation" (since we're coining that term) use a method like RIPS, by the way. RIPS uses the regulation capabilities of our power supplies, whereas many of those other amps that claim equal power at different impedances simply run out of current at lower impedances and use soft-clipping schemes to take the edge off. RIPS is not a "soft" power supply, quite the opposite.


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## lycan (Dec 20, 2009)

msmith said:


> Not sure why you think it's crude or undesirable... it's just optimizing the voltage/current ratio to best suit the applied load and allowing the full power capability of the amp to be deployed into that load.
> 
> For example, if you're running a "2 ohm" subwoofer driver in a sealed box, your minimum impedance will generally be closer to 4 ohms. RIPS will make sure you get twice the power in that situation compared to the same amp without RIPS. To the user, that's a "2 ohm subwoofer system", but it's really not. In car audio, we need to deploy a wide range of speaker systems and all kinds of subwoofer systems in all kinds of enclosures that have different impedance characteristics.
> 
> ...


When the _minimum_ impedance is well ABOVE the specified, marketed, or nominal value ... i certainly agree with you


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## lycan (Dec 20, 2009)

lycan said:


> Would it be fair to say the following :
> 
> *If i want a fair, valid comparison between a RIPS amp and a non-RIPS amp, i really must compare specified power levels at the MINIMUM value of loudspeaker impedance ... rather than the "marketed" value, or "nominal" value?*
> 
> ...


what say you, good sir?


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## msmith (Nov 27, 2007)

lycan said:


> When the _minimum_ impedance is well ABOVE the specified, marketed, or nominal value ... i certainly agree with you


I would amend that to say "at, near or above the specified, marketed, or nominal value", as is the case with almost any subwoofer system and competently designed component system. (why do I feel like I'm being deposed for a patent trial, or something... sheeesh)

We build a big cushion into the system... it's not like full clipping at 3.9, or even 3.5 ohms will trip it out of 4 ohm setting. It has some brains behind it to account for the real-world stuff.


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## lycan (Dec 20, 2009)

i've been deposed ... a bunch of times. worst thing ever. a day-long game, where the best you can hope for is a draw.


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## msmith (Nov 27, 2007)

lycan said:


> Would it be fair to say the following :
> 
> *If i want a fair, valid comparison between a RIPS amp and a non-RIPS amp, i really must compare specified power levels at the MINIMUM value of loudspeaker impedance ... rather than the "marketed" value, or "nominal" value?*
> 
> ...


No, I would not agree with that statement. I can't get into the specific reasons why, but I can say we designed it for real-world conditions and real-world speaker loads.


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## msmith (Nov 27, 2007)

lycan said:


> i've been deposed ... a bunch of times. worst thing ever. a day-long game, where the best you can hope for is a draw.


Me too.. Bob Carver vs. API... I'll tell you the story some time, but I will need beer.


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## lycan (Dec 20, 2009)

msmith said:


> No, I would not agree with that statement. I can't get into the specific reasons why, but I can say we designed it for real-world conditions and real-world speaker loads.


*Then how do you account for this inescapable difference between these two "100 watt" amplifiers, if we don't compare the amps at minimum impedance :*



lycan said:


> Let's assume a "so-called" 4-ohm speaker with an impedance that drops, over some range, to 2.5 ohms. Not un-common, i think.
> 
> Let's use that McIntosh amp : 100 watts into 4 ohms, 200 watts into 2 ohms, all with low distortion. This amp can happily drive that load, with low distortion, to 30 volts across the whole frequency range. That will equate to 100 watts for freqs where the impedance is 4 ohms, and 160 watts for freqs where the impedance is 2.5 ohms. Agreed?
> 
> ...


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## msmith (Nov 27, 2007)

lycan said:


> *Then how do you account for this inescapable difference between these two "100 watt" amplifiers, if we don't compare the amps at minimum impedance :*


Because it's badass, that's why!. :laugh:

Seriously though, because they're not really "100 watt" amplifiers, if you want to have a fair comparison.

The McIntosh that you are describing is actually a 200W amp at 2 ohms that happens to make less power at 4 ohms (100W). It is, nevertheless a 200W amplifier... that is its optimum design power, that's what its power supply and outputs were designed to do.

For a fair comparison, the RIPS amp would also make 200W at 2 ohms (and, because it has RIPS could also make 200W @ 4 ohms if the nominal impedance is actually higher). 

If the RIPS amp is in its 2 ohm gear (making 200W @ 2 ohms), it will only make 100W at 4 ohms and behave exactly like the McIntosh driving the same load.

Now, let's say the RIPS amp is in its 3 ohm gear because your "2 ohm load" can be driven safely in that gear, you get more power from the RIPS amp than the McIntosh.

Bottom line is that a conventional (non-RIPS) amp is always stuck in the lowest RIPS gear, whereas the RIPS amp gives you the ability to have higher rail voltage, when possible, to get more power at higher impedances than the amp's minimum safe impedance. Why is this hard to understand?

As I said before, not all amps that exhibit equal power specs at different impedances work the same way. My comments apply only to the JL design.

BTW... I think we have successfully confused the daylights out of any casual observer of this thread.

I'm going home now... I'm tired.


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## lycan (Dec 20, 2009)

msmith said:


> Because it's badass, that's why!. :laugh:
> 
> Seriously though, because they're not really "100 watt" amplifiers, if you want to have a fair comparison.
> 
> ...


And exactly how is this NOT comparing the amps at MINIMUM load impedance, exactly as i suggested? Please re-read the 160 watts statements, above.


> If the RIPS amp is in its 2 ohm gear (making 200W @ 2 ohms), it will only make 100W at 4 ohms and behave exactly like the McIntosh driving the same load.
> 
> Now, let's say the RIPS amp is in its 3 ohm gear because your "2 ohm load" can be driven safely in that gear, you get more power from the RIPS amp than the McIntosh.
> 
> Bottom line is that a conventional (non-RIPS) amp is always stuck in the lowest RIPS gear, whereas the RIPS amp gives you the ability to have higher rail voltage, when possible, to get more power at higher impedances than the amp's minimum safe impedance. Why is this hard to understand?


Why is it hard to understand that this is identical to comparing amps at MINIMUM impedance ... just like i suggested we do?


> As I said before, not all amps that exhibit equal power specs at different impedances work the same way. My comments apply only to the JL design.
> 
> BTW... I think we have successfully confused the daylights out of any casual observer of this thread.


That's OK ... not all threads need to be targeted to casual readers.

Some will follow, and understand.

The bottom line is that power should be compared at MINIMUM expected impedance levels. According to this line of thought, the speaker I described is a 2.5-ohm load, not a 4-ohm load. The 100W McIntosh amp will deliver 160 watts to this load (over the freqs where it's 2.5 ohms, rather than 4 ohms). If (and we're still not quite clear on this) the 100W RIPS amp has trouble delivering 160 watts to this 2.5 ohm load, the VALID comparison should be with a RIPS amp that's specified as a 160 watt amp (including 2.5 ohms in its impedance range).

Compare the amps at MINIMUM expected impedance ... not "marketed", not "nominal". You're saying the same thing


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## Oliver (Jun 25, 2007)

lycan said:


> i've been deposed ... a bunch of times. worst thing ever. a day-long game, where the best you can hope for is a draw.





msmith said:


> Me too.. Bob Carver vs. API... I'll tell you the story some time, but I will need beer.


_I'm thinking some micro-brewery and perhaps a designated driver when this is discussed_


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## Oliver (Jun 25, 2007)

So... If I understand this , the trick is to design a transmission for a sports car that will do the same speed regardless of what gear I am in.

1rst gear - 100 mph or 1rst, 2nd and 3rd will all combine to equal 100 mph.

*This is gonna be one expensive transmissio*n :surprised:

_______________________________________________________________________________________



> THE SPEAKER
> 
> The speaker I have in mind is simply this :
> 
> ...


It will manage with an automatic transmission ..., But in order to excel ..., we would need a manual or standard type shift to keep our power level in an optimum position as we got going down the road.


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## lycan (Dec 20, 2009)

I want to carefully articulate this point, one step at a time, before I pack it in for a while. I may return to this post. *IF NOBODY READS ANY OTHER POST, THIS IS A GOOD SUMMARY SO FAR (in my mind, anyway)*.

Step-by-step:

1. I've got a speaker that varies in impedance (over frequency) from 4 ohms to 2 ohms. *I don't care how it is marketed*. I think we've already agreed, that this range is _not_ that crazy ... especially if we consider multi-element speakers, with passive crossovers.

2. I'm going to drive it with a very sophisticated 100 Watt RIPS amp. This amp has many levels of rail settings, and a very sophisticated algorithm for detecting impedance levels in the load. It's rated at 100 Watts in 4-ohms, 100 Watts into 3-ohms, and 100 Watts into 2-ohms.

3. Our 100 Watt RIPS amp "detects" that the _minimum_ speaker impedance is, indeed, 2-ohms (over some frequency range) ... and it sets the rails accordingly. This means that the rails are set at +/- 20 volts (plus maybe one or two for output stage devices). This allows the amp to deliver it's specified power of 100 Watts to the load, over the frequency range where it's 2-ohms. The rails "latch" here, and stay here.

4. Now, the question is : what standard, voltage-source amp will compare most directly to this 100 Watt RIPS amp, when driving the load which varies from 4-ohms to 2-ohms? Very simple : one with +/- 20 volt rails. *One that delivers 100 Watts to 2-ohms. One that delivers 50 Watts to 4-ohms.*

*In summary* : a RIPS amp must be compared to a standard amp, _at the minimum value of load impedance_.

*We see above, that a RIPS amp that delivers 100 Watts to a reactive load, compares directly to a standard amp that delivers 100 Watts to the minimum of that reactive load. In the case examined above, with 2x load variation over frequency, the 100 Watt RIPS amp ... at 4-ohms, 3-ohms, or 2-ohms ... compares directly to a standard amp that supplies 50 Watts to 4-ohms, and 100 Watts to 2-ohms.*

That's what I mean, when i say that these amps must be compared _at the minimum expected load impedance_ ... no matter how the impedance is "described" or "marketed".

Are any of these detailed points in error? i don't think so ....


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## cobra93 (Dec 22, 2009)

lycan said:


> And exactly how is this NOT comparing the amps at MINIMUM load impedance, exactly as i suggested? Please re-read the 160 watts statements, above.
> Why is it hard to understand that this is identical to comparing amps at MINIMUM impedance ... just like i suggested we do?
> That's OK ... not all threads need to be targeted to casual readers.
> 
> ...


I'm sure both of you know way more about amps than I do, but If I'm understanding msmith correctly. The 300/2 is rated @ 150 watts into 1.5-4 ohms (I own 2 of them) but in reality ( based on you're minimum impedance) it should be rated at 300 watts x 2 @ 2 ohms plus headroom, even higher at 1.5 ohm loads. However since the amp isn't designed to deliver that much power without self destructing you're buying a 150 x 2 rms capable amp @ multiple impedance/loads (R.I.P.S.).

Since msmith is unable to tell you how far below 4 ohms and for how long is required for the amp to latch to the next lower rail voltage the two of you may never be able to resolve this.

If I understand what msmith is saying, you (lycan) may be looking at this from the opposite point of view as msmith, half the power @ 2ohms, not double the power @ 2 ohms.

Is this correct?

You posted your last post while I was typing this one.

I believe that the amp is doing what every any other amp does, delivers power, until the current exceeds it's limits then it lowers its rail voltage and stays there until you exceed its limits again. 
I believe this is a current limiting system, I don't believe the amp cares what the ohm load is, only its current output.


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## lycan (Dec 20, 2009)

cobra93 said:


> I'm sure both of you know way more about amps than I do, but If I'm understanding msmith correctly. The 300/2 is rated @ 150 watts into 1.5-4 ohms (I own 2 of them) but in reality ( based on you're minimum impedance) it should be rated at 300 watts x 2 @ 2 ohms plus headroom, even higher at 1.5 ohm loads. However since the amp isn't designed to deliver that much power without self destructing you're buying a 150 x 2 rms capable amp @ multiple impedance/loads (R.I.P.S.).
> 
> Since msmith is unable to tell you how far below 4 ohms and for how long is required for the amp to latch to the next lower rail voltage the two of you may never be able to resolve this.
> 
> ...


Read post #51 carefully 

RIPS is _trying_ to ratchet down it's supply rails, in order to SAFELY deliver it's _rated power_ into the MINIMUM load impedance. Period. We can debate the success ... how closely it achieves it's goal ... but that's my understanding of what it's TRYING to do. It doesn't ratchet the rails "up", and once they are set "low" ... they never raise (until power is cycled).

SO ... it will compare to a standard amp that delivers the SAME power to the MINIMUM value (over frequency) of the reactive load. It's really that simple.

It can obviously be applied to ANY load impedance, with ANY variation from Zmin to Zmax.

Post #51 ... that's my understanding so far.


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## cobra93 (Dec 22, 2009)

I don't believe the amp is TRYING to latch to a lower rail voltage, it only does so due to design (not burning up).

This is my understanding ( my post # 52)


> If I'm understanding msmith correctly. The 300/2 is rated @ 150 watts into 1.5-4 ohms (I own 2 of them) but in reality ( based on you're minimum impedance) it should be rated at 300 watts x 2 @ 2 ohms plus headroom, even higher at 1.5 ohm loads. However since the amp isn't designed to deliver that much power without self destructing you're buying a 150 x 2 rms capable amp @ multiple impedance/loads (R.I.P.S.).


Which is why I said you get 1/2 the power @ 2 ohms, not double.


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## Oliver (Jun 25, 2007)

> Now, let's say the RIPS amp is in its 3 ohm gear because your "2 ohm load" can be driven safely in that gear, you get more power from the RIPS amp than the McIntosh.
> 
> Bottom line is that a conventional (non-RIPS) amp is always stuck in the lowest RIPS gear, whereas the RIPS amp gives you the ability to have higher rail voltage, when possible, to get more power at higher impedances than the amp's minimum safe impedance. Why is this hard to understand?


Sums it up fairly well.


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## cobra93 (Dec 22, 2009)

Oliver said:


> Sums it up fairly well.


I thought so as well.


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## lycan (Dec 20, 2009)

(I really need to sleep) .. but consider this post as a *COMPANION* to post #51.

Let's now ask what happens if i take the two amps identified in post #51, and apply them to a DIFFERENT speaker ... one whose impedance varies from 8-ohms to 4-ohms? Which amp "fares better" ... which one delivers more power to this new, DIFFERENT load?

It will be easy to demonstrate that the RIPS amp will deliver more power to this new, different load :

1. RIPS : The algorithm will deliver 100 watts to the minimum impedance of 4-ohms, thereby delivering 50 watts at those freqs where the impedance is 8 ohms.

2. Standard amp : if we use the SAME standard amp identified in post #51, it will deliver only 50 watts where the impedance is 4 ohms, and a paltry 25 watts where the impedance is 8 ohms.

*CONCLUSION : There's a HUGE difference when we discuss "load variation". Do we mean ... variation from one speaker i might connect versus another, OR do we mean reactive impedance variation (over frequency) for the SAME speaker?

TWO VERY DIFFERENT QUESTIONS !!!!!!!!!!!!!!!!!!!!!!!*

We ALL have to be careful NOT to confuse the two.

OK ... this is all making sense to me, i think. These TWO posts are my understanding so far


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## cobra93 (Dec 22, 2009)

Oliver said:


> So... If I understand this , the trick is to design a transmission for a sports car that will do the same speed regardless of what gear I am in.
> 
> 1rst gear - 100 mph or 1rst, 2nd and 3rd will all combine to equal 100 mph.
> 
> ...


I completely missed the post above the quote. I thought you were being sarcastic. I'm with you now.:thumbsup:

O.T. How do I get her to deliver packages to me?


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## cobra93 (Dec 22, 2009)

I believe you've summed it up in your last post, but I think you're over thinking this.
If an amp uses rips or not it's still doing the same job, as in you 2 examples, delivering power.


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## lycan (Dec 20, 2009)

cobra93 said:


> I believe you've summed it up in your last post, but I think you're over thinking this.
> If an amp uses rips or not it's still doing the same job, as in you 2 examples, delivering power.


of course, all amps deliver power ... but how much?

if i have a SINGLE speaker that varies from 4 ohms to 2 ohms (reactive, over frequency) a 100W RIPS amp compares to a standard amp that's 50W/4-ohm, 100W/2-ohm. It does NOT compare to a standard amp that's 100W/4-ohm, 200W/2-ohm.

That's a significant conclusion! That's the essence of post #51. And it doesn't depend, at all, how the speaker is "marketed".


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## cobra93 (Dec 22, 2009)

> if i have a SINGLE speaker that varies from 4 ohms to 2 ohms (reactive, over frequency)


All speakers are reactive loads, that's the point I'm trying to convey.



> And it doesn't depend, at all, how the speaker is "marketed".


The amp doesn't care how the speaker is marketed. RIPS or not the amp simply sends power to the speaker.



> 100W RIPS amp compares to a standard amp that's 50W/4-ohm, 100W/2-ohm.It does NOT compare to a standard amp that's 100W/4-ohm, 200W/2-ohm


I believe this is the problem, a 100 watt rips amp is a 200 watt amp @ 2 ohms, only with a current limiting "governor".

I'm not trying to argue with you, This is how rips was explained to me some time ago .


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## cobra93 (Dec 22, 2009)

I'd like msmith to confirm these statements above.


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## lycan (Dec 20, 2009)

cobra93 said:


> All speakers are reactive loads, that's the point I'm trying to convey.
> 
> 
> The amp doesn't care how the speaker is marketed. RIPS or not the amp simply sends power to the speaker.
> ...


Nope ... it's not. A 100 Watt RIPS amp can't deliver 200 Watts, while still somehow "limiting current" (can't get the power, without the current!). It adjusts its supply rails (downward), so that it delivers 100 Watts to the lowest impedance it detects.

For any SINGLE speaker, a 100 Watt RIPS amp will deliver 100 watts to the MINIMUM impedance it detects ... and _lower_ power to frequency ranges where the impedance is _higher_ (because the rails are now "latched" in place). That's post #51.

*A 100 Watt RIPS amp compares to a 50W/4-ohm (100W/2-ohm) amp, for a SINGLE speaker whose reactive impedance varies from 2-ohms to 4-ohms. For a SINGLE speaker, the powers must be compared at the minimum impedance.

HOWEVER, on a DIFFERENT speaker whose reactive impedance varies from 4-ohms to 8-ohms, that SAME 100 Watt RIPS amp compares to a 100W/4-ohm amp ... because this new, different speaker has a different minimum of 4 ohms.*

These are important distinctions ... and it's why i've concluded that RIPS must be compared to standard amps at the _minimum_ value of reactive load impedance.


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## cobra93 (Dec 22, 2009)

lycan said:


> Nope ... it's not. A 100 Watt RIPS amp can't deliver 200 Watts, while still somehow "limiting current". It adjusts its supply rails (downward), so that it delivers 100 Watts to the lowest impedance it detects.
> 
> For any SINGLE speaker, a 100 Watt RIPS amp will deliver 100 watts to the MINIMUM impedance it detects ... and _lower_ power to frequency ranges where the impedance is _higher_ (because the rails are now "latched" in place). That's post #51.
> 
> ...


I believe you need to reread post #21 by msmith.



> Now, inevitably, a ‘creative thinker’ comes along and wonders what happens when we take the amp designed to make 500W at 4 ohms and connect it to a 1 ohm load! Well, since it has 44.7V rails and is not a sentient being, this amp will try to deliver 2000W into a 1 ohm load, which requires 44.7A of current… and here we have a problem as the designer never intended it to be able to do this and the amplifier gets really pissed off and hot and either shuts down to protect itself, blows a fuse or catches on fire


This quote says the same thing I've been stating, where the amplifier is halving the output at 2 ohms, not doubling it because it's not designed to output that much voltage and amperage.


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## lycan (Dec 20, 2009)

cobra93 said:


> I believe you need to reread post #21 by msmith.
> 
> 
> 
> This quote says the same thing I've been stating, where the amplifier is halving the output at 2 ohms, not doubling it because it's not designed to output that much voltage and amperage.


Check the specs of a RIPS amp. See if it doubles it's rated power, at half the impedance. See if it halves the rated power, at half the load impedance.

Or ... is it designed to deliver the SAME power across a VARIETY of impedances? What this means in practice, is that it will adjust the supply rails (downward) to deliver rated power into the minimum load impedance it detects. Why? Because burning up amps that keep trying to deliver MORE power into LOWER impedances is exactly what RIPS is trying hard to avoid.

Do you take issue with any specific steps outlined in post #51?


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## cobra93 (Dec 22, 2009)

I think you're thinking of rips a a crutch, only getting 1/2 the power.
When I look at rips as getting 2 times the power into 4 ohms.

rips isn't designed to give 1000 watts @ 2ohms ( the500/1 for instance), therefore it can't/won't.
It will however sacrifice twice the power @ 2 ohms (1000 watts) to deliver full power @ 4-1.5 ohms, hence you're getting 1/2 power at 2 ohms.

Does what I'm saying make any sense to you? I'm not asking if it answers your question or not, just if it makes sense.


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## cobra93 (Dec 22, 2009)

> it halves the rated power, at half the load impedance


This is exactly my point.



> it halves the rated power, at half the load impedance,it designed to deliver the SAME power across a VARIETY of impedance


You've just stated the same thing I've been saying all along, but you seem to believe the opposite.



> Do you take issue with any specific steps outlined in post #51?


I've reread post #51 and I disagree with point number 4 and below.


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## cobra93 (Dec 22, 2009)

I believe that a 100 watt rips amp (if the circuitry is capable) would be rated @ 400 watts @ 1 ohm without rips.


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## thehatedguy (May 4, 2007)

That's why when I had my slash series amps, I ran 300/4s bridged rather than 300/2s stereo- I knew my load would never fall below 4 ohms, and in most cases be way above 4 ohms. The bridged 300/4 made the same power as the 300/2, just that it did it between 4 and 8 ohms rather than 1.5-4 ohms.

Did it work as intended? Hell if I know, I don't really know how RIPS works either...but it sounded like a good idea at the time.

Side note, WTF is up with the tool kit of allen wrenches that comes with the HD amps?


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## cobra93 (Dec 22, 2009)

I don't claim to understand exactly how this all works.
I'm only stating what makes sense (to me) after I read post #21 by msmith and how rips was explained to me a long time ago.
I could be full of sh!t and I don't deny it.


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## lycan (Dec 20, 2009)

cobra93 said:


> I think you're thinking of rips a a crutch, only getting 1/2 the power.
> When I look at rips as getting 2 times the power into 4 ohms.
> 
> rips isn't designed to give 1000 watts @ 2ohms ( the500/1 for instance), therefore it can't/won't.
> ...


yes, i think that THIS does make sense. And i think that's what Manville has been saying too 

BUT ... i'm not thinking of it as a crutch. I'm just breaking it down further, so I can understand what happens with a single, reactive load versus two different loads. And i think this summarizes the answer (even if it sounds complicated, it's really not):

*IN SUMMARY : RIPS tries to deliver rated power to the minimum impedance it detects.* This has two implications, glass half-empty vs. glass half-full (so to speak):

*Glass half-empty*: If a single speaker is connected, with impedance variation (over freq) of 2-ohms to 4-ohms, a 100W RIPS amp compares to standard amp of 50W/4-ohms (100W/2-ohms). Both amps deliver 100 Watts where the speaker is 2-ohms, and both deliver 50 Watts where the speaker is 4-ohms.

*Glass half-full*: Take that SAME RIPS amp, and put it on a HIGHER impedance speaker, with variation of 4-ohms to 8-ohms. You NOW need a different, more powerful, standard amp rated at 100W/4-ohms to compare.

As i said, i find it instructive to consider "two dimensions" to the concept of "load variation". One dimension is, load variation (with frequency) for the _same_ speaker. The other is, load variation with _different_ speakers connected.

So ... does the RIPS amp "suffer" at low impedances, or does it "benefit" at higher impedances? I think the way i've broken it down, the answer is : BOTH 

Why bother? It's instructive to anyone who wants to compare amplifiers, i think.


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## cobra93 (Dec 22, 2009)

thehatedguy said:


> That's why when I had my slash series amps, I ran 300/4s bridged rather than 300/2s stereo- I knew my load would never fall below 4 ohms, and in most cases be way above 4 ohms. The bridged 300/4 made the same power as the 300/2, just that it did it between 4 and 8 ohms rather than 1.5-4 ohms.
> 
> Did it work as intended? Hell if I know, I don't really know how RIPS works either...but it sounded like a good idea at the time.
> 
> Side note, WTF is up with the tool kit of allen wrenches that comes with the HD amps?


I considered going the bridged 300/4 instead of the 300/2 on my components for that very reason as well, would it make a difference, I've got no idea.


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## lycan (Dec 20, 2009)

cobra93 said:


> This is exactly my point.
> 
> 
> 
> ...


why? Point #4 in post #51 is hard to argue with: If the RIPS amp has +/- 20V rails (after they are set and left alone), then it compares to a standard amp with +/- 20V rails.

And i asked you if a RIPS amp:

1. Halves its rated power at half the impedance, or
2. Doubles its rated power at half the impedance, or
3. Keeps its rated power constant across a range of impedances

It can't do ALL of these  I've argued that it does #3, and I've argued the reason why ... or, more specifically, what #3 means in practice.


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## cobra93 (Dec 22, 2009)

lycan said:


> yes, i think that THIS does make sense. And i think that's what Manville has been saying too
> 
> BUT ... i'm not thinking of it as a crutch. I'm just breaking it down further, so I can understand what happens with a single, reactive load versus two different loads. And i think this summarizes the answer (even if it sounds complicated, it's really not):
> 
> ...


I think I can agree with your last post, I think of rips as a positive.

One variable remains, maybe the one answer you were looking for that neither of us can answer: at what conditions does the rips amp latch to a lower rail voltage? 
To me that seems to be the "root" question. I think that would be the answer to your initial question, disregarding the reactive load, because rips or not both amps would be living in the same "world".


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## cobra93 (Dec 22, 2009)

I was referring to:


> We see above, that a RIPS amp that delivers 100 Watts to a reactive load, compares directly to a standard amp that delivers 100 Watts to the minimum of that reactive load. In the case examined above, with 2x load variation over frequency, the 100 Watt RIPS amp ... at 4-ohms, 3-ohms, or 2-ohms ... compares directly to a standard amp that supplies 50 Watts to 4-ohms, and 100 Watts to 2-ohms


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## lycan (Dec 20, 2009)

cobra93 said:


> I think I can agree with your last post, I think of rips as a positive.
> 
> One variable remains, maybe the one answer you were looking for that neither of us can answer: at what conditions does the rips amp latch to a lower rail voltage?
> To me that seems to be the "root" question. I think that would be the answer to your initial question, disregarding the reactive load, because rips or not both amps would be living in the same "world".


Although i don't know the specifics, it seems that the amp is really attempting to determine the speaker's impedance ... more specifically, it's _minimum_ impedance. *It will set the supply rails to deliver it's rated power to that minimum*. It may not have great "resolution" in measurement, or rail "choices" ... but that's that's the "target algorithm" in a nutshell.

From that point, the rails are "latched", and it behaves just like any amp ... _with that same rail setting_.

If i'm right (tbd) ... the consequences, for a single reactive speaker vs. different speakers, are summarized above.


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## cobra93 (Dec 22, 2009)

I think we "mostly " agree. 
My thinking (different than yours) is that it looks at volts/amps only and adjusts from there.
It would seem (from reviews I've read and what DS-21 posted) the amp hits a power threshold and throttles back. This is my basis for the argument against ohm load. 
However, we are arguing them very same thing since the lower the ohm load the higher the output. I guess that makes us both correct until someone says we're wrong. 
Agreed?


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## cobra93 (Dec 22, 2009)

I think we're allot alike. We're not just going to accept something we're told, it has to make sense. If it doesn't, I want to see it for myself.


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## Niebur3 (Jul 11, 2008)

lycan said:


> yes, i think that THIS does make sense. And i think that's what Manville has been saying too
> 
> BUT ... i'm not thinking of it as a crutch. I'm just breaking it down further, so I can understand what happens with a single, reactive load versus two different loads. And i think this summarizes the answer (even if it sounds complicated, it's really not):
> 
> ...


Is this why when I compared a 600/4 (3-channels worth) to 2 channels of a Tru B-475 and 1 channel of a Tru B-4100, it seemed as if the Tru amp have more power and was more dynamic than the JL, especially when I cranked the volume, even though the JL was rated much higher in terms of wattage?


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## KP (Nov 13, 2005)

My take on this:

For a '2 ohm' driver:

Rips 100x2 @ 4 = non Rips 50x2 @ 4

For a 4ohm driver:

Rips 100 x 2 @ 4 = non Rips 100 x 2 @ 4

For a 8ohm driver:

Rips 100 X 2 = non Rips 200 X 2

Seems the key is how Rips determines what the impedance 'is'.


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## rommelrommel (Apr 11, 2007)

This is an old post by Richard Clark:

from observation it appears that the JL amp monitors output current into the load and assumes that if the current exceeds a certain amount it must be driving a load that is lower than the supply can safely handle----if this condition is sensed it switches to a lower rail voltage that keeps it within its power design limits-----the difference from a conventional class G amp is that the JL never switches back to the higher rail till it is powered down-----from what I can observe the amp never switches to the lower supply as long as the drive signal is kept low-------so in that respect it is sort of like a "one way" class G design.........RC


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## lycan (Dec 20, 2009)

rommelrommel said:


> This is an old post by Richard Clark:
> 
> from observation it appears that the JL amp monitors output current into the load and assumes that if the current exceeds a certain amount it must be driving a load that is lower than the supply can safely handle----if this condition is sensed it switches to a lower rail voltage that keeps it within its power design limits-----the difference from a conventional class G amp is that the JL never switches back to the higher rail till it is powered down-----from what I can observe the amp never switches to the lower supply as long as the drive signal is kept low-------so in that respect it is sort of like a "one way" class G design.........RC


pretty much how i see it.

EDIT : noting, of course, that the comment about the rails "never switching to the lower supply" if the drive signal is "kept low" is rather pointless. If there's a "burst" of loudness, by virtue of signal dynamics or a quick twist of the volume knob, the power rails will _ratchet down and remain low_ (as i understand it) ... even if the volume control is subsequently reduced. Bottom line : the RIPS algorithm is searching for the lowest value of the load impedance, and will ratchet down the supply rails ... if & when successful ... to deliver rated power _at that lowest impedance_.


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## lycan (Dec 20, 2009)

Niebur3 said:


> Is this why when I compared a 600/4 (3-channels worth) to 2 channels of a Tru B-475 and 1 channel of a Tru B-4100, it seemed as if the Tru amp have more power and was more dynamic than the JL, especially when I cranked the volume, even though the JL was rated much higher in terms of wattage?


It's plausible ... assuming other variables were well isolated & controlled, of course (brand names hidden, gains matched, no marketing shenanigans in rating either amp, etc.).

*RIPS will try to "determine" the lowest value of the load impedance, and set the supply rails to safely deliver rated power to that lowest impedance (protecting the amp in the process). I know the algorithm doesn't have infinite "resolution" or "granularity" to achieve this with utmost precision ... but that's the "intent" as i understand it.*

Nothing wrong with that! It just makes a direct comparison with other (non-RIPS) amps a bit more ... challenging 

If a RIPS amp is rated at 100 watts over a wide range of impedances, that means it will set the rails to deliver 100 watts to the _minimum_ value of a very reactive load (assuming it "detects" that impedance minimum). So ... that RIPS amp must be compared to a standard amp that delivers 100 watts to the _minimum_ value of that reactive load (rather than the "nominal", or "marketed" value of the load).

EDIT : it's all "spelled out" in post #51, for a _single_ speaker. Look to post #57, for a continuation over _different_ speakers. My understanding of it, all the pieces seem to fit.


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## Oliver (Jun 25, 2007)

> *the JL never switches back to the higher rail till it is powered down*


Try this:

Hold a resistor across the speaker contacts as the amp is powered on

can be a resistor the halves the impedance , just like wiring a DVC in parallel.

After it is on and playing the amp in theory will be locked in until power down.

Now lift the resistor off the speaker out puts !


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## ncv6coupe (Oct 25, 2009)

Lycan seems that the answer you *really* want it what the rips "brain" requires (length of time of whatever load across the output) to "reduce rail voltage for that run cycle." Manville said transients doesn't affect the amps so Does it matter that the Slash amps contain enough capacitance to maintain 3db of headroom "ALL THE TIME" supposedly and I think it would be user error to buy a 300/4 to power a set of 8 ohm speakers for anything other than bass where we can almost predict impedance plots ex. ported enclousure tuning?

forgot to add, when we bang on speakers hard and the parameters start to change as the VC heats up and what not, if the rips is locked in high voltage mode, as resistance begins to rise is that not a good thing ?


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## lycan (Dec 20, 2009)

hey me no hater, me no say it's bad.

All me sayn is this : If the RIPS routine senses the _minimum_ of a reactive impedance curve (which seems to be its goal) ... you've got a RIPS amp that delivers it's rated power to the _minimum_ of the impedance curve.

Just make sure you compare it to a standard amp that delivers the same power to that impedance _minimum_. That's all 

No magic ... just gotta understand where its rail voltage gets set, for a given load (with possible variation over frequency, naturally).


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## ncv6coupe (Oct 25, 2009)

oh no, i wasn't implying that at all, It just caught me off guard that someone with your work experience was thrown for a loop about the RIPS technology(not really realistically). I like how we got lots and lots of information from this post about what we should be looking for in amplifiers to expect "*linear real world power*"*cough*. Thanks Should I even mention Voltage dips I don't remember if it was discussed earlier, what happens when your 5000 watt class D amp is pulling lots of juice and your mid amp is getting 11.2 DC volts.


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## lycan (Dec 20, 2009)

cajunner said:


> there's probably a current threshold that has to be peaked for RIPS to ratchet down to the next step down on the rail voltage adjustment range.
> 
> I'm guessing that it's not as simple as "okay, a 4 ohm mid that droops to 2 ohms in the middle of it's power band is going to mean that my 4 ohm power level is automatically configured for 2 ohm rails"


it would be lovely to know for sure 

Why _wouldn't_ it do this? Is the amp happy (low distortion, low thermal stress) delivering _twice_ it's rated power ... for those frequencies where the impedance is halved?


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## lycan (Dec 20, 2009)

cajunner said:


> that's the "Regulated" part of RIPS, I suspect that if car voltage droops to 11.1 volts, then instead of the amp pulling excessive amounts of current, it'll begin limiting power to the load based on supply issues.
> 
> I'm thinking that the two work together, but if you look at the test on the 300/2, voltage from 12 to 14.4 didn't budge, but further decreases from 12 might.


you're confusing LOAD regulation, with SUPPLY regulation. Two different things.

See ... everyone thought this was simple 

check my last post again ... for my conundrum.


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## lycan (Dec 20, 2009)

cajunner said:


> I guess that depends on how much thermal leeway/cutback they have designed into the sink?
> 
> If the amp *can* deliver full output according to heatsink real estate, into 4 ohms, and then do it again, at 3, 2, and 1.5, wowee, right?


Yes ... the amp can deliver 100 watts into 4 ohms, 100 watts into 3 ohms, 100 watts into 2 ohms, 100 watts into 1.5 ohms. I've got no problem there.

The question is : what about a load that's 4 ohms for some frequencies, and 2 ohms for other frequencies? Does it really deliver 100 watts into 4 ohms, and 200 watts into 2 ohms for this reactive speaker? I don't get the impression ... from the specs, or from the description ... that the amp would be happy doing this. I think the amp is trying to sense the lowest impedance value, and deliver its 100 Watts _there_ ... which means, only 50 Watts available for the freqs where the impedance is 4 ohms.


> I'm thinking that the RIPS amp is just getting what every one wants out of the amp.
> 
> And it's marketing that drives this technology, probably as much as the returns on warranty does.
> 
> If you are sold an amp that is only good for a 4 ohm mono load, and you start off with one sub, the loving thing to do is to give your amp 2 ohms to deal with, because that's how we do...


Remember the VALUE PROPOSITION i've made in this analysis 

Separate out these two issues :

1. Load variation over a SINGLE SPEAKER
2. Load variation over one speaker you connect today, versus a second speaker you might connect tomorrow


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## Oliver (Jun 25, 2007)

> "*Regulated*"* means* that the power supply adjusts its operation so as to maintain the amplifier's rated power output and low distortion operation *over a wide range of vehicle voltages* (11V-14.5 V).


Car Audio Amplifiers - Car Audio Amps - JL Audio

Some amps give* less power out* when they are fed* less power in*.


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## lycan (Dec 20, 2009)

cajunner said:


> in other words, a RIPS amp is not the typical 2 ohm rated and value-added power, it's value-added convenience, and durability.


CORRECT.


> With RIPS, you buy a 150 watt/ch amp, that's what you get. You're not buying a 300 watt/ch at 2 ohm capable, 150 watt/ch amp.


*CORRECT !!!!!!*


> Is this backwards thinking? From what ace956 has said, he would prefer to get more power out of an amp's components by reducing impedance and adding output transistors. Old school, current hogs that have to be run at specific impedances, because the projection is that if you don't lower the resistance you're not getting all the power you paid for.
> 
> If you get a 4 ohm rated, "cheap-o" amp and run components off it, you're feeling pretty good because all the watts are paid for, none of that hidden "8 woofers and I'm finally feeling I got my money's worth" type of thinking.


Again, all i'm saying is this : you're buying an amp that delivers RATED power, same number of watts, over a wide impedance range. It's designed for durability, and flexibility _should you change speakers_. But while you're sticking with a _single speaker_, the amp is going to try to deliver it's rated power to the minimum reactive value of load impedance ... otherwise, you'll be asking it to deliver MORE than its rated power (at low distortion, with low thermal stress) over some bandwidth. 

This is not a "bad" proposition, for an amp ... just compare it to the PROPER standard amp _for that same load_.

EDIT : this is all based on my understanding, described in detail in posts #51 and #57.


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## Oliver (Jun 25, 2007)

> Conventional amplifiers are designed to produce optimum power at a particular impedance (2 ohm, for example). When asked to run above that impedance (say, 4 ohm), these amplifiers lose power (half their power from 2 ohm to 4 ohm). This will not happen with a JL Audio Slash v2 amplifier because the R.I.P.S. System detects the actual impedance being driven and adjusts output rail voltages to deliver optimum output.





lycan said:


> Nope ... it's not. A 100 Watt RIPS amp can't deliver 200 Watts, while still somehow "limiting current" (can't get the power, without the current!). It adjusts its supply rails (downward), so that it delivers 100 Watts to the lowest impedance it detects.
> 
> For any SINGLE speaker, a 100 Watt RIPS amp will deliver 100 watts to the MINIMUM impedance it detects ... and _lower_ power to frequency ranges where the impedance is _higher_ (because the rails are now "latched" in place). That's post #51.
> 
> ...


Like so ?


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## ncv6coupe (Oct 25, 2009)

Manville, We'll be here waiting for you in the AM buddy.  It's almost like this is a new product about to hit the market and we are demanding solid straight from the horse's mouth answers! haha


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## lycan (Dec 20, 2009)

i really gotta go to sleep.

JUST KEEP THIS DISTINCTION IN MIND :

1. Ask what the amp does for a single speaker, whose impedance varies (with frequency) from some Zmin to some Zmax. Understanding "where" the rails get set, will determine what "standard" amp it will directly compare to ... for that load. Either the amp "seeks out" the minimum reactive impedance, or it's "happy" (low distortion, low thermal stress) putting out substantially MORE than rated power (over some bandwidth). Given this choice ... I suspect it's "seeking out" the minimum. That's post #51.

2. Ask what the amp will NOW do, if you change speakers to a _different_ impedance range. That's post #57. It's a _separate_ question.

In my mind, it's imperative to ALWAYS keep this distinction in mind.


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## Oliver (Jun 25, 2007)

JUST KEEP THIS DISTINCTION IN MIND :



> 2. Ask what the amp will NOW do, if you change speakers to a _different_ impedance range. That's post #57. It's a _separate_ question.
> 
> In my mind, it's imperative to ALWAYS keep this distinction in mind.


Could you hook an 8 ohm speaker up and play it?

Then a 2 ohm speaker?

would this answer what he is asking?


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## lycan (Dec 20, 2009)

Oliver said:


> JUST KEEP THIS DISTINCTION IN MIND :
> 
> 
> 
> ...


Of course you can. But you have to dig deeper ...

1. What's the impedance variation, over frequency, of the 8-ohm speaker? Where will RIPS set the rails? Then we know, what "standard" amp to compare it to ... for this impedance. This is a version of post #51 ... only, with different numerical values of impedances picked (for demonstration).

2. Now ... what's the impedance variation, over frequency, of the 2-ohm speaker? Where will the SAME RIPS amp set the rails for this load? Then we know, what "standard" amp to compare it to ... for this impedance. This is another (separate) version of post #51.

*PUNCHLINE *: The "standard amps" discovered in 1. and 2. will be DIFFERENT amps. Hence, the _flexibility_ of the single RIPS amp  That's post #57.


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## lycan (Dec 20, 2009)

cajunner said:


> we could just say that we're paying for the convenience of knowing no matter what speaker combination we end up with, we're covered.


sure, we're covered ... but at what power level? The amp won't blow up, so we won't need to send it back for warranty work ... if that's what you mean by "covered". But what if i ask : "what "standard amp" can i compare it to, for load configuration xyz?" Are the rails indeed set for RATED power delivery into the minimum value of reactive load?


> and, that the cost of RIPS is buried in that convenience, not necessarily that we aren't achieving maximum efficiency for dollar/watt ratios.
> 
> Also, RIPS is a computerized manipulation of the Pulse Width Modulation, and is "intelligent" enough to keep the amp out of thermal runaway zones, and the average installer in good sound and out of warranty repair hotlines.
> 
> I'm sayin' it's 50/50, you lose on watts per dollar but you get something else out of it, and because the distortion stays down for all impedances chosen, you don't get the distortion rise and the efficiency bite when your amp tries to double down.


Yes ... it's the "safe choice"


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## lycan (Dec 20, 2009)

cajunner said:


> what Power Guard does for McIntosh is limit current based on some kind of opto-coupling follower circuit thingy, so that the amp is never driven into distortion-bearing modes; wouldn't RIPS also then limit destructive "end wattage" based on running on a lower rail voltage? As a speaker protection scheme, I know it's got that square wave thing to worry about, but if total power delivered to the speaker is being limited based on a lower voltage differential, isn't that working out as a current limiting device as well, considering that a sine wave that looks square, is just 1/3 more output and that's it?
> 
> Is this relatively unimportant, or does the real world pay dividends in less blown speakers as a result of RIPS not throwing a bunch of power into the load due to low resistance and high drive?


OK ... this is my last post for the night ... for realz.

In my mind, the best McIntosh feature to compare this to, is NOT PowerGuard ... but rather the McIntosh Autoformer  I'm not kidding.

Howz that?


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## Oliver (Jun 25, 2007)

lycan said:


> Of course you can. But you have to dig deeper ...
> 
> 1. What's the impedance variation, over frequency, of the 8-ohm speaker? Where will RIPS set the rails? Then we know, what "standard" amp to compare it to ... for this impedance. This is a version of post #51 ... only, with different numerical values of impedances picked (for demonstration).
> 
> ...


*This would save a novice money in the long run* 


If a person was lacking adequate skills electronically , the amplifier would not self destruct as fast as a cheaper amp that was abused by asking for too much out with too little in.:surprised:


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## Oliver (Jun 25, 2007)

> It would seem that in description, the RIPS amp should be rated by it's 4 ohm power, against other amps that are rated into 4 ohms.




For an apples to apples


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## msmith (Nov 27, 2007)

lycan said:


> (I really need to sleep) .. but consider this post as a *COMPANION* to post #51.
> 
> Let's now ask what happens if i take the two amps identified in post #51, and apply them to a DIFFERENT speaker ... one whose impedance varies from 8-ohms to 4-ohms? Which amp "fares better" ... which one delivers more power to this new, DIFFERENT load?
> 
> ...


I agree that the root of our inability to agree lies in this distinction and what is meant by the term "minimum impedance". 

As stated earlier, the RIPS amplifier does not directly measure impedance, but rather monitors a "current envelope" to decide which gear to engage. This mechanism is designed to account for the reactive nature of a typical loudspeaker load, so a very narrow or transient impedance dip will not necessarily make the amplifier shift down to a lower rail voltage. In real-world use, the system can even allow crazy amounts of clipping into a 4 ohm nominal load without shifting down. It is far from a 'hair-trigger' mechanism as we don't want it to shift down if the amp can handle the load at the higher voltage.

In other words, the RIPS "decision mechanism" is calibrated to respond to NOMINAL, not minimum impedance values. When tested with a resistor, there is no difference between the nominal and the minimum impedance value, so you might see the amplifier shift down very predictably at some power figure slightly above its rated power. With a reactive load, RIPS allows the amp to produce significantly more power than with a purely resistive load of the same nominal value (see CarSound measurements posted earlier in this thread), which is what a really good amplifier should be able to do.


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## MACS (Oct 3, 2007)

lycan said:


> OK ... this is my last post for the night ... for realz.
> 
> In my mind, the best McIntosh feature to compare this to, is NOT PowerGuard ... but rather the McIntosh Autoformer  I'm not kidding.
> 
> Howz that?


That's what I was thinking . Also thinking it can be had for a lot less money with the JL, since the MCC602TM is the only car version of the Autoformer amp.


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## msmith (Nov 27, 2007)

lycan said:


> OK ... this is my last post for the night ... for realz.
> 
> In my mind, the best McIntosh feature to compare this to, is NOT PowerGuard ... but rather the McIntosh Autoformer  I'm not kidding.
> 
> Howz that?


Tis true, except we don't hang a nasty transformer on the output of our amplifier. 

Who remembers the transformers that someone was selling in the early 90's to artificially lower the impedance of your speaker system and get more power? "Accumatch", I think they were called.


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## lycan (Dec 20, 2009)

cajunner said:


> Quick question I asked previously:
> 
> Is RIPS at all able to help save speakers, or does the circuit basically have no effect on speaker VC sizzle? It sounds like the same condition that resets the voltage is also responsible for allowing massive current dumping into a load, which is (my guess volume knob related.


the load regulation part of RIPS is designed to protect the amplifier ... not the speakers

If you put a 500W RIPS amp on a coil that can't handle 500W, and crank the volume ... the speaker fries (but not the amp).


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## lycan (Dec 20, 2009)

msmith said:


> I agree that the root of our inability to agree lies in this distinction and what is meant by the term "minimum impedance".
> 
> As stated earlier, the RIPS amplifier does not directly measure impedance, but rather monitors a "current envelope" to decide which gear to engage. This mechanism is designed to account for the reactive nature of a typical loudspeaker load, so a very narrow or transient impedance dip will not necessarily make the amplifier shift down to a lower rail voltage.


I don't think we disagree that much. Without knowing the specific details of the algorithm, I can appreciate that a "very narrow" impedance dip, or a quick "transient" won't "necessarily" cause the amp to ratchet down the rails 

However ... as outlined in post #51 ... it's certainly conceivable that a speaker whose impedance varies _more gradually_ between 2-ohms and 4-ohms (don't care how the 'nominal value' is marketed) will cause the algorithm to select the 2-ohm rails. How do I know this? Simple application of logic ... plus the recognition that speakers have an impedance RISE near resonance. The RIPS algorithm is surely NOT "selecting" the rails based on the _highest_ impedance displayed by the speaker!


> In real-world use, the system can even allow crazy amounts of clipping into a 4 ohm nominal load without shifting down. It is far from a 'hair-trigger' mechanism as we don't want it to shift down if the amp can handle the load at the higher voltage.


Once again, i agree. It's undoubtedly not a "hair trigger".


> In other words, the RIPS "decision mechanism" is calibrated to respond to NOMINAL, not minimum impedance values. When tested with a resistor, there is no difference between the nominal and the minimum impedance value, so you might see the amplifier shift down very predictably at some power figure slightly above its rated power. With a reactive load, RIPS allows the amp to produce significantly more power than with a purely resistive load of the same nominal value (see CarSound measurements posted earlier in this thread), which is what a really good amplifier should be able to do.


We absolutely agree on it's behavior into a resistive load 

I hate the word "nominal", because i don't know what it means ... it's too ambiguous. That's why i've avoided it since post #51. The concepts of "maximum impedance" and "minimum impedance" are much more meaningful to me. And i would offer that the "intent" of the RIPS algorithm is to more closely focus-on, or measure, the "minimum value" ... rather than the "maximum value" ... to adjust rails for amplifier protection.

But i can certainly appreciate that there's some "extra headroom" built into the algorithm to allow for quick "transients", or "sharp impedance dips".


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## lycan (Dec 20, 2009)

cajunner said:


> my perhaps illogical question, is what happens when the "current envelope" that RIPS monitors, does actually trip the 'not-hair trigger' latching down a notch?
> 
> I suspect that if you have a 30 volt at 4 ohm amp, and make it latch at 20 volts due to a lot of current passing through it for an extended period, you'd have a built-in safety margin designed into it that saves speakers due to less power "through coils" based on heating times.
> 
> ...


Power kills coils.

Once the rails are set, the RIPS amp behaves _just like_ a regular voltage source amp _with the same rail setting_. So the RIPS amp will be just as likely to kill (or not) a speaker, compared to a standard amp with the same supply rails.

The RIPS rail selection is designed to protect the amp, not the speaker.


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## lycan (Dec 20, 2009)

cajunner said:


> I think I get it now. Lycan, you're saying RIPS is basically a glorified overload protection circuit that in real world, reactive impedance situations is likely to reduce power unnecessarily, and Manville is saying that is not likely to happen unless the amplifier is indeed, being stressed by the higher output.
> 
> I'm siding with Manville on this one, because the dynamic nature of music rarely makes use of, or attempts to produce "sine-wave" power demands on an amplifier.
> 
> The harshest conditions that would require "ratcheting down" are probably rap music beats with the extended passages of bass, most other music won't cause the amp to run into the red and get "unhappy"


Let's pick some speaker bandwidth. Let's assume that over 30% of that bandwidth, the speaker's impedance is 2-ohms. Over 70% of that bandwidth, the speaker is 4-ohms.

BUT the music content that i'm playing ... quite loudly, thank you  ... is such that 60% of the time, i'm playing loudness over the 2-ohm fraction of bandwidth.

Where do you think RIPS will set the rails?

Without knowing the specific details of the algorithm, but understanding that it's not a "hair trigger" that reacts to "quick spikes" ... what do you think the INTENT of the algorithm is?

EDIT: RIPS is designed to PROTECT THE AMP. Make no mistake about it. If the particular situation is demanding too much power, the rails will ratchet down. In this way, it's an algorithm designed to "seek out" the impedance _minimum_. Certainly, a 'quick transient' poses no _thermal danger_ to the amp ... so the algorithm is _insensitive_ to it  But the basic intent ... "on average", over time, if you will ... is to find the _minimum_ and set the rails accordingly ... to protect the amp.


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## 14642 (May 19, 2008)

lycan said:


> what do you think the INTENT of the algorithm is?


 
Hmmm...reduce tech support calls that sound like this, "yeah bro, but how many wattses does the amp bump out at a half ohms?"

I think it's to simplify system design for installers and consumers who can't figure out how to connect woofers to optmize a load for a voltage source.


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## lycan (Dec 20, 2009)

Without knowing the details of the algorithm (i understand the proprietary nature), but knowing the INTENT ... i'll stand by this :

EDIT: RIPS is designed to PROTECT THE AMP. Make no mistake about it. If the particular situation is demanding too much power, the rails will ratchet down. In this way, it's an algorithm designed to "seek out" the impedance minimum. Certainly, a 'quick transient' poses no thermal danger to the amp ... so the algorithm is insensitive to it But the basic intent ... "on average", over time, if you will ... is to find the minimum and set the rails accordingly ... to protect the amp.


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## lycan (Dec 20, 2009)

Andy Wehmeyer said:


> Hmmm...reduce tech support calls that sound like this, "yeah bro, but how many wattses does the amp bump out at a half ohms?"
> 
> I think it's to simplify system design for installers and consumers who can't figure out how to connect woofers to optmize a load for a voltage source.


hey what the hell are you doing in this here sandbox ???


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## lycan (Dec 20, 2009)

Guys, this thread was spawned by that god-forsaken train wreck about amps & headunits sounding the same  

Thanks to manville, and others, i've learned what i set out to learn 

My final word of advice, especially to those really setting out to compare different amps ... in a "lab", or in the "real world" (i say that in jest, because there's no difference):

For a valid comparison between a RIPS amp and a non-RIPS amp ... *measure the rail voltages* when driving a particular load, to make sure the comparison is fair. Do NOT simply rely on advertised power specs ... for either amp ... especially with very reactive loads 

I don't think that's unreasonable 

me done


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## msmith (Nov 27, 2007)

lycan said:


> I hate the word "nominal", because i don't know what it means ... it's too ambiguous. That's why i've avoided it since post #51. The concepts of "maximum impedance" and "minimum impedance" are much more meaningful to me. And i would offer that the "intent" of the RIPS algorithm is to more closely focus-on, or measure, the "minimum value" ... rather than the "maximum value" ... to adjust rails for amplifier protection.


Yes, I know the word "nominal" seems like a weak term, but keep in mind that impedance dips aren't really the trigger... current demand is... the signal, gain, and the load all play a role in the current demand. An impedance dip by itself will never put an amp in distress.


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## mosca (Oct 26, 2009)

still trying to wrap my head around this...

now, for me the question from the other thread still remains: would we be able to tell a RIPS amp from another one? (discounting the regulated power supply part).

I'm akin to infer that we would be able to do it, since with an impedance dip (o current demand) relevant enough one would put more power, but the other one would adjust to this new scenario.


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## msmith (Nov 27, 2007)

lycan said:


> Without knowing the details of the algorithm (i understand the proprietary nature), but knowing the INTENT ... i'll stand by this :
> 
> EDIT: RIPS is designed to PROTECT THE AMP. Make no mistake about it. If the particular situation is demanding too much power, the rails will ratchet down. In this way, it's an algorithm designed to "seek out" the impedance minimum. Certainly, a 'quick transient' poses no thermal danger to the amp ... so the algorithm is insensitive to it But the basic intent ... "on average", over time, if you will ... is to find the minimum and set the rails accordingly ... to protect the amp.


Okay, wait a minute. 

If you claim that RIPS is designed to protect the amp, then you must also categorically admit that *a singular, fixed low rail voltage also is designed to protect an amp.* 

In other words, an amp that makes [email protected] ohms and only [email protected] ohms is using a low rail voltage to make sure that some idiot doesn't try to make 200W @ 2 ohms with it. The penalty is less power when you have to use it at a higher impedance. Lots of amps work this way and none that I'm aware of tell you to use them only at 4 ohms or higher... they all optimize to 2 ohms or lower which automatically compromises 4 ohm output.

Contrast the above amp with a RIPS amp that is 100W @ 2 ohms or 4 ohms and it becomes clear that the purpose of RIPS is to deliver the full design power of the amplifier at higher impedances, as well as lower impedances.

The twist that RIPS provides is the ability to have a higher rail voltage at 4 ohms and an automatic way to prevent the application error (we all know what people do if this is left to a manual switch), so if you want to look at it as a protection system that's up to you, but that's not really it's primary reason for being. We didn't sit around and say "let's protect the daylights out of these amps"... we said "let's make full power, regardless of the load." If anything, this works our amps HARDER, not easier, so we have to make sure they are pretty bulletproof running at FULL DESIGN POWER, because they *always* will.

We feel the benefits of this are significant when it comes to real-world application. Let's say the subwoofer you're using is only available as a 4 ohm driver or consider that most component speaker systems have a 4 ohm nominal impedance. RIPS opens up a lot of application flexibility and is able to deliver full power at the higher impedance loads. I find the extra headroom on my component speakers to be quite welcome.

Another example: amplifiers that make 1 kW of clean power at 4 ohms are pretty rare... the 1000/1v2 has been doing it for a decade, thanks to RIPS... maybe you want to run a W7 (3 ohms): you also get 1 kW... maybe you want to run two 4 ohm subs in parallel... you also get 1 KW... or maybe two W7's in parallel (1.5 ohms)... you guessed, it: 1 kW. If we surgically removed RIPS from the 1000/1v2 it would only make 500W at 4 ohms.

Our dealers and customers really like this flexibility and I feel pretty strongly that it is a major reason why RIPS enabled amps have been at the top of the sales charts for a decade. The Slash amps also outsold every single non-RIPS amp we ever had concurrently. I realize these are not technical points, but success in the market does give an indication that the product delivers value that people appreciate.


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## lycan (Dec 20, 2009)

msmith said:


> Now, somebody who thinks a little deeper comes along and says. “You know, it sure sucks that we have to load the amp down to get all the power that was designed into it. It would be great if we could tell the amp what the load is so that it can always make its full power.” A well-meaning engineer overhears this reasonable request, and says… “We can do that! We’ll simply put a switch marked “2 ohms or 4 ohms” and let the user select the appropriate position for his application. *The switch will lower the rail voltage at the 2 ohm position so the amp is still 500W and doesn’t catch on fire.* (Soundstream and Sony did this a while back).
> 
> Seems like a really smart, reasonable solution to give the customer the 500W he paid for every time, right? Only one problem: the amp gets louder when you put it in the 4 ohm switch position and connect it to a 2 ohm load, and someone posts that on DIYMA and everybody starts to do it,* and pretty soon everyone is complaining that the amp is a P.O.S. because it catches on fire.*
> 
> So, then another engineer comes along and says “We must make this function automatic and transparent to the user.” and the ancestor of RIPS is created. (PPI 2350DM in the early 90’s). This amplifier had two settings (2 ohm and 4 ohm) that it selected automatically by detecting the load’s impedance through a current measurement on the output of the power supply at clipping. This clever piece of engineering cost some dollars to implement and took some time to tweak and perfect, *but in essence gave this amp an automatic version of the “2 ohm or 4 ohm” switch, so that people couldn’t select the wrong position and burn the amp up.* So, this unique amp was rated to produce 350W x 2 @ 4 ohms or 2 ohms. It should be noted, that during operation the amp will never switch back and forth from the “2 ohm” to the “4 ohm” rail voltage… it picks one and stays there, behaving just like a regular old fixed rail voltage source amplifier.


Your words, in describing how & why RIPS was invented .... compared to, for example, a user-selectable "switch." And no ... i wasn't quoting "selectively". Those are three consecutive paragraphs from your description.

The process of ratcheting *down* the rail setting ... and NEVER moving back upward ... is designed to protect the amp.

I have already explained the FLEXIBILITY of a RIPS amp in driving DIFFERENT speakers. I've done so MANY times in this thread, in fact ... as I developed this important distinction of "load variation" : impedance variation over frequency for a _single_ speaker, versus impedance variation over _multiple_ speakers (beginning with posts #51 and #57).

I have never complained about the market value of RIPS amps.

I'm out.


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## ncv6coupe (Oct 25, 2009)

In the real world has anyone on here driven their rips amps hard enough to shut down on them, what did it do when it powered back up and started playing again? I haven't seen much talk about this anywhere. Manville do you mind sharing any details you know about the controlled lab test JL put their amps through up to the point of failure?


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## gijoe (Mar 25, 2008)

msmith said:


> we said "let's make full power, regardless of the load."


I feel that this is a misrepresentation of what is happening. Compared to a standard, non-rips amp, you aren't making full power regardless of the load, you are making the SAME power regardless of the load.

Regular amps make full power regardless of the load, it just isn't the same amount of power. Your system reduced the power, therefor it isn't FULL power, it's just the same.

This isn't intended to be a negative comment, I've never used JL equipment, and I'm certainly not opposed to the company or it's products in anyway. I just feel that Lycan's description of it being for protection is more accurate than your claim to it being to produce full power at any load. It doesn't do that.


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## msmith (Nov 27, 2007)

gijoe said:


> I feel that this is a misrepresentation of what is happening. Compared to a standard, non-rips amp, you aren't making full power regardless of the load, you are making the SAME power regardless of the load.
> 
> Regular amps make full power regardless of the load, it just isn't the same amount of power. Your system reduced the power, therefor it isn't FULL power, it's just the same.
> 
> This isn't intended to be a negative comment, I've never used JL equipment, and I'm certainly not opposed to the company or it's products in anyway. I just feel that Lycan's description of it being for protection is more accurate than your claim to it being to produce full power at any load. It doesn't do that.


Yes, RIPS does not reduce power within its range of usable impedances, it maintains power. Would it change your mind if it started at the lowest voltage and then ratcheted up? Would it then be "gaining power"?

Regular amps (without RIPS) do not make all the power the amplifier is capable of with different loads. Their rail voltage and current capabilities are optimized for one particular load and one load only. At loads lower than the optimum one, the amp will current limit or protect... at loads higher it will produce less power and you are not using the full power capabilities of the circuit. 

RIPS simply provides a mechanism for the amplifier to deliver the full design power at various loads (within a certain range of values)... above that range the amp loses power just like a normal amp, and below that range, the amp current limits or protects just like a normal amp. 

So, the bottom line is "do you want the full power the amp is capable of at one load impedance only, or over a range of useful load impedances?"


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## msmith (Nov 27, 2007)

ncv6coupe said:


> In the real world has anyone on here driven their rips amps hard enough to shut down on them, what did it do when it powered back up and started playing again? I haven't seen much talk about this anywhere. Manville do you mind sharing any details you know about the controlled lab test JL put their amps through up to the point of failure?


About the only thing that will shut a RIPS amp down completely is when supply voltage drops really low (like below 10V)... this triggers a protective shut-down. Once the voltage climbs back up the amp turns back on but does not cycle RIPS as it would with a deliberate off-on cycle.


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## Niebur3 (Jul 11, 2008)

lycan said:


> Guys, this thread was spawned by that god-forsaken train wreck about amps & headunits sounding the same


Sorry to have started that "train wreck" thread when lots of great information was discussed, spawning this thread as well. Next time I will try to NOT understand and ask questions that maybe seem basic in content, but are designed to open great discussions.


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## msmith (Nov 27, 2007)

lycan said:


> Your words, in describing how & why RIPS was invented .... compared to, for example, a user-selectable "switch." And no ... i wasn't quoting "selectively". Those are three consecutive paragraphs from your description.
> 
> The process of ratcheting *down* the rail setting ... and NEVER moving back upward ... is designed to protect the amp.
> 
> ...


The first paragraph states the reason for going to all the trouble. The others explain the pitfalls of a manual switch and the benefits of an automatic system and are simply aimed at describing the history of development and the thinking behind it. 

It's a glass half-empty / glass half-full issue, I guess. Some see a protection system and a limiting of power at lower impedances and they worry that you're not getting more power than at higher impedances. This is driven by the fact that we've become accustomed to amps that behave a certain way.

I have the benefit of actually having been at the meetings where the decisions to green-light RIPS were made. So, I actually know the reasons we did it. I've tried my best to explain them.


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## lycan (Dec 20, 2009)

(double post)


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## lycan (Dec 20, 2009)

msmith said:


> It's a glass half-empty / glass half-full issue, I guess.


Indeed it is :



lycan said:


> yes, i think that THIS does make sense. And i think that's what Manville has been saying too
> 
> BUT ... i'm not thinking of it as a crutch. I'm just breaking it down further, so I can understand what happens with a single, reactive load versus two different loads. And i think this summarizes the answer (even if it sounds complicated, it's really not):
> 
> ...


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## msmith (Nov 27, 2007)

Now why don't you guys go bother Wehmeyer and ask him how Logic 7 works!


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## lycan (Dec 20, 2009)

Niebur3 said:


> Sorry to have started that "train wreck" thread when lots of great information was discussed, spawning this thread as well. Next time I will try to NOT understand and ask questions that maybe seem basic in content, but are designed to open great discussions.


oh geez ... no offense intended to the author of the thread.

you try arguing logic & reason to a bunch of audiophiles over the internet ... for the better part of a decade ... you'd be bitter too! :mean:

(i can guess Manville & Andy's reaction : "Arguing with them? ARGUING? Hell, that's a walk in the park! Try _supplying products_ to them !!! LOL)

which reminds me ... why the hell am i here?


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## thehatedguy (May 4, 2007)

You want to see a train wreck? Go over to DIYAudio and read some of the posts where people were arguing with Jeff about DACs and how they work. I mean nevermind that Jeff was on the design team of the first multibit DAC. But some armchair expert knows more about it than he does.


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## thehatedguy (May 4, 2007)

He probably got confused like all of the consumers who confuse JL and JBL. Know how many times I was asked for a JBL 12W7?



lycan said:


> hey what the hell are you doing in this here sandbox ???


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## ncv6coupe (Oct 25, 2009)

i was gonna share my amp story then i changed my mind now i'll share it for you caj. i tried really hard to shut down a 300/2 amp powering my subwoofer a couple months ago and was unsuccessful. Granted that was with music but 2 ohms, 150 RIPS watts was enough for my neighbor to come across the street and ask me to turn the bass down from shaking her house 75 feet across but what the amp did do though was drain my pos oem battery cells out where it couldnt crank the car and that battery is now in heaven, too much discharges thanks to rips current draw and it was replaced by a 900 cca diehard platinum, the amp never did budge nor distort even above (optimal) rail voltage levels... when i went 5 oclock on the gain, and i was sitting right next to the sub in the car on the floor and there wasnt any audible distortion either. I believe in RIPS. I did retardedly mess up that amp though by unplugging the rcas with the system powered up and the jack slipping and grounding out on the radio chassis, i regret that to this day, amp is sitting in the garage, reminds me i should get it fixed again.


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## Niebur3 (Jul 11, 2008)

lycan said:


> oh geez ... no offense intended to the author of the thread.
> 
> you try arguing logic & reason to a bunch of audiophiles over the internet ... for the better part of a decade ... you'd be bitter too! :mean:
> 
> ...


Did I guilt you in to helping me (us) yet?!?


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## tornaido_3927 (Nov 23, 2009)

Soooo, in regard to the RIPS system behaving a certain way with a single speaker, which has only one impedance curve.. 
What happens when someone uses 2 RIPS amps in a system with each amp driving only one side (left OR right) of the speaker pairs?

For example, having two 4-channel RIPS amps each driving a tweeter (4 ohms), a mid (6 ohms), midbass (8ohms) and a sub (2 ohms) rather than one amp running two tweeters and two mids, and the other amp running two midbasses and two subs.

Does the amp set the rails for ALL channels or as pairs, or individually?

I don't know if this is really a big issue or anything, but I think some people are fans of having separate amps driving each side of the cars' speakers.


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## kyheng (Jan 31, 2007)

As far as I know(reading from the manual), 1.5-4ohm is constant rated output while 8ohm would be 50% from the rated output. That's why I get myself a HD750/1 for an 8ohm 300W sub.


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## msmith (Nov 27, 2007)

tornaido_3927 said:


> Soooo, in regard to the RIPS system behaving a certain way with a single speaker, which has only one impedance curve..
> What happens when someone uses 2 RIPS amps in a system with each amp driving only one side (left OR right) of the speaker pairs?
> 
> For example, having two 4-channel RIPS amps each driving a tweeter (4 ohms), a mid (6 ohms), midbass (8ohms) and a sub (2 ohms) rather than one amp running two tweeters and two mids, and the other amp running two midbasses and two subs.
> ...


In most models that use RIPS, the RIPS adjusts independently for each channel pair or mono subwoofer channel. The only exception to this is the 300/4 and 300/4v2, which adjusts globally for all 4 channels. All the other amps have independent RIPS for each channel pair or mono sub channel.

If you bridge a pair of channels, RIPS will adjust between 3-8 ohms.


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## taibanl (Jun 19, 2011)

So what will rips do when it sees my 2.7 ohm voice coil (totalling 3.3ohm at the amp including wires)?


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## dwhite832003 (Jan 19, 2013)

Wow really sorry to revive this old thread guys but this lamen here just needs to know what final load sub ssetup is better for the hd series? 4ohm or 2 ohm final load?


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## msmith (Nov 27, 2007)

dwhite832003 said:


> Wow really sorry to revive this old thread guys but this lamen here just needs to know what final load sub ssetup is better for the hd series? 4ohm or 2 ohm final load?


Either one is fine.


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## dwhite832003 (Jan 19, 2013)

@ msmith! From an earlier post by you 

A)Amp turns on and wakes up in the 4 ohm setting (highest rail voltage)

B)	If the user never turns it up loud and never clips the amp, it will stay in the high-voltage setting (yes, with craploads of headroom if you’re running a low impedance).

That last bit is what is confusing me!


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## dwhite832003 (Jan 19, 2013)

A: If I'm running a 4 ohm reactive load & it fluctuates to say 6ohms the power will be reduced but if it fluctuates to a lower impedance rips does its thing & stabilizes it's output! 

B: Now if I'm running a 2 ohm reactive load & it fluctuates to 4ohms rips still gives me full output, but if it fluctuates to a lower impedance say 1 ohm the amp gets put into protection mode! 
Is this why you guys make dual 1.5ohm subs?


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## TrickyRicky (Apr 5, 2009)

Have anyone read the manual? Especially the part where you set the gain......you, the user/owner, adjust the voltage output according to your load.

If you know how to do a simple little math (rms) you'll see why you have to lower the voltage on a lower load while increase it to its max with a 4 ohm load or higher.



Should i do an example??



If your worried about a load fluctuating, you should see it while playing music.


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## msmith (Nov 27, 2007)

The load can never drop below the DC resistance of the voice coils and will almost never drop below the nominal impedance, either. 

RIPS adjusts to the nominal load and tolerates minor fluctuations. It is a very well developed and proven technology.


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## dwhite832003 (Jan 19, 2013)

msmith said:


> The load can never drop below the DC resistance of the voice coils and will almost never drop below the nominal impedance, either.
> 
> RIPS adjusts to the nominal load and tolerates minor fluctuations. It is a very well developed and proven technology.


Wow thank you! That's all I needed to know!


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## 14642 (May 19, 2008)

And furthermore, speaker impedance isn't some wacky thing that just moves all over the place. It isn't a wet lasagne noodle. It's a resistor (length of wire in the coil), an inductor (the wire is configured in a coil), and a resonance (a combination of capacitance and inductance). The resonance (the big peak in the impedance curve) is caused by the cone's motion (attributed to inertia--it either tries to stay stationary or tries to continue moving once it's set in motion), which generates a potential (voltage) which causes current to flow in opposition to the flow of current from the amplifier. We express that voltage as resistance. The motion of the cone is controlled by the moving mass and the compliance of the speaker. The strength of the motor (size of the magnet and number of turns in the voice coil) determines how that voltage is created (how much voltage and over what frequency range--that's Q).


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## msmith (Nov 27, 2007)

^^^ Yup.


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## t3sn4f2 (Jan 3, 2007)

Andy Wehmeyer said:


> And furthermore, speaker impedance isn't some wacky thing that just moves all over the place. It isn't a wet lasagne noodle. It's a resistor (length of wire in the coil), an inductor (the wire is configured in a coil), and a resonance (a combination of capacitance and inductance). The resonance (the big peak in the impedance curve) is caused by the cone's motion (attributed to inertia--it either tries to stay stationary or tries to continue moving once it's set in motion), *which generates a potential (voltage) which causes current to flow in opposition to the flow of current from the amplifier.* We express that voltage as resistance. The motion of the cone is controlled by the moving mass and the compliance of the speaker. The strength of the motor (size of the magnet and number of turns in the voice coil) determines how that voltage is created (how much voltage and over what frequency range--that's Q).


And to dumb that part down a bit more. A voice coil moving through (ie back and forth) a magnetic field (ie the speaker's magnet) will produce energy (like a generator) that opposes the energy coming into the speaker from the amp.


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## 14642 (May 19, 2008)

^^ like the alternator in your car


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## Ihakmsnt (Jun 6, 2013)

Do you know anything about the JL HD 600/4 ? I need info on setting up in 3 channel mode if possible.


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## chad (Jun 30, 2005)

Many here use the HD series, you are probably better off just starting a thread.


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## TheBlindMan (Feb 7, 2013)

Ihakmsnt said:


> Do you know anything about the JL HD 600/4 ? I need info on setting up in 3 channel mode if possible.



Have you looked at the manual?


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## Ihakmsnt (Jun 6, 2013)

I read in the manual that it could be done but how and what switch's tpdo you set to what?


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## clix`g35 (Aug 23, 2009)

So basically, the Channel pairs, on a 600/4 1-2 and 3-4 should have the same drivers or drivers with similar impedance loads since they are adjusted by RIPS in pairs?

I want to confirm this before I wire everything up wrong, I was initially inclined to go left on one amp and Right on the other, now I think the correct thing to do is set tweets in 1-2 pair, mids in 3-4 pair, etc.

Thanks!


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## quietfly (Mar 23, 2011)

This thread was a very cool Hidden jewel... see, procrastination at work finally got me something useful!!!


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## cleansoundz (May 14, 2008)

Subscribed


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## rich20730 (Feb 13, 2012)

Does anyone know how RIPS compares to Zapco's Intelligent Rail Voltage Control? It seems like a similar concept, but I haven't really been able to find much information on it, other than the vague description in the manual.


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## Schramm (Mar 12, 2012)

Some of the responses on this thread indicate a complete lack of understanding of ohms law and real world inductance variation common to most drivers and passive crossovers. JL Audio R.I.P.S technology appears to be a sophisticated amplifier protection circuit, designed to accommodate various load types. Plain and simple. I see no other real benefit to the technology. It is misleading if anyone markets it or understands it as something different.

A driver with nominal impedance of X ohms will become an increasingly difficult load to drive as impedance drops with frequency. It is important to understand the real world impedance variation and select an amplifier accordingly, based on minimum impedance it will see. Selecting drivers with nominal impedance below 4 ohms presents significant stress on almost any amplifier and can add significant distortion. Lycan's comments are valid.


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## diegoejea (May 11, 2009)

lycan said:


> Without knowing the details of the algorithm (i understand the proprietary nature), but knowing the INTENT ... i'll stand by this :
> 
> EDIT: RIPS is designed to PROTECT THE AMP. Make no mistake about it. If the particular situation is demanding too much power, the rails will ratchet down. In this way, it's an algorithm designed to "seek out" the impedance minimum. Certainly, a 'quick transient' poses no thermal danger to the amp ... so the algorithm is insensitive to it But the basic intent ... "on average", over time, if you will ... is to find the minimum and set the rails accordingly ... to protect the amp.


As far as i understood about R.I.P.s technology, it is not ony to protect the amp. It also makes possible to design an amplifier "optimized" for such power. i find it really clever. I will explain myself:

When you have a regular amp you design to work with 4 Ohms and 2 Ohms loads, you will have the same rails voltage for the 2 different impedances. So you have to oversize the amplifier internals to support the increased current and power at 2 Ohms. This makes a waste of resources, and size, if you use the amp at 4 Ohms only. 

Well, some of you will prefer an oversize designed amp. But, what if you want to optimize the amp size, and you want to keep offering the possibiity of using either 4 or 2 Ohms? 

One of the answers is RIPS. You offer "X" full watts for all impedances, and you make the amplifiers to change rail voltage intelligently, according to the load. 

This is my opinion, and if I am not wrong, I find it a really clever solution. I want my amplifiers size optimized, whitout any lack of power. I don´t like a wasted trunk area


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