# GaN FET Based Amplifiers



## rton20s

There has been some recent comments on Facebook regarding a "revolutionary" new amplifier from Soundigital out of Brazil. The key to the new amp is apparently the use of GaN FETs. One of the only other applications I have seen on the audio side of things is a couple of systems from Technics. *So, any of the DIYMA amp gurus have any feedback?*

The specific Soundigital amp in question, the SD300.2D...
Soundigital Amplifiers - Lançamento SD300.2 GaN Power

http://soundigitalusa.com/wp-content/uploads/2016/02/final_final.pdf


































More info on GaN (Gallium Nitride) FETs...
Class D Audio

EPC9106 EPC | Programmers, Development Systems | DigiKey

The Panasonic/Technics use of the tech...
Panasonic breathes new life into Technics


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## redit

rton20s said:


> EPC9106 EPC | Programmers, Development Systems | DigiKey


$1,300?!


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## rton20s

redit said:


> $1,300?!


I was hoping for a bit more feedback than this, but yes, the EPC 9106 development board is $1338. If the Soundigital SD300.2D uses the same (or similar) board, it would explain the $1500-$2000 retail pricing that was mentioned on FB. 

Among some other benefits stated by the EPC, one of the things that stuck out to me was the switching speed of 400+ kHz. This is on par with what JL is doing with their HD amps and greater than what they have in their XD amps. I have no idea how that compares to other Class D amps, but since we see switching speeds this high in the HDs I don't believe this alone will make GaN FETs a "game changer." 

I was really hoping Ricky, Victor, deveds50 and some of the other amp pros around here might be willing to chime in.


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## Nismo

Forgive me, but doesn't increased switching speed mean lower efficiency? I always thought you wanted just enough speed, not too much for audio.

Eric


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## rton20s

Nismo said:


> Forgive me, but doesn't increased switching speed mean lower efficiency? I always thought you wanted just enough speed, not too much for audio.
> 
> Eric


I have no idea, but I would guess no. Just based on the claims of 90+% efficiency.


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## Focused4door

Nismo said:


> Forgive me, but doesn't increased switching speed mean lower efficiency? I always thought you wanted just enough speed, not too much for audio.
> 
> Eric


Not switching frequency, switching speed which is essentially transition time from on to off. Fast switching speed means you don't have the FET in a resistive region for as long.


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## AccordUno

I can tell you that I will be using them in the near future I knew about these back in Dec and got to see the amp at SBN. So Until I have mine I can't say much, but will definitely be interesting..

I am currently running 2 - soundigital 800.4 and switching out to 2 400.4D and one 800.4, so far, I'm very happy with the power in the small package.. lot less power consumption and having the ability to have my hatch back..


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## rton20s

AccordUno said:


> I can tell you that I will be using them in the near future I knew about these back in Dec and got to see the amp at SBN. So Until I have mine I can't say much, but will definitely be interesting..
> 
> I am currently running 2 - soundigital 800.4 and switching out to 2 400.4D and one 800.4, so far, I'm very happy with the power in the small package.. lot less power consumption and having the ability to have my hatch back..


I look forward to seeing your feedback.


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## Justin Zazzi

I want to know what the middle of the paragraph in the first image is referring to. Something about QRR? QPR? I can't really read it. It says it's related to distortion, and class D amps have low amounts of it, but these new transistors have zero amounts of it. What is that all about?


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## rton20s

Jazzi said:


> I want to know what the middle of the paragraph in the first image is referring to. Something about QRR? QPR? I can't really read it. It says it's related to distortion, and class D amps have low amounts of it, but these new transistors have zero amounts of it. What is that all about?


I know absolutely nothing about this (hence my initial post), but I can use google and "Ctrl+C" and "Ctrl-V" like nobodies business!



EPC eGaN FETs and ICs for Class D Audio Applications said:


> The quality of sound reproduced by the audio amplifier, measured by THD (Total Harmonic Distortion), DF (damping factor), and IMD (intermodulation distortion) is influenced by the characteristics of the power transistors used.
> 
> eGaN FETs’ near ideal switching performance due to lower propagation delays and faster slew rates (due to their lower gate capacitance) and zero QRR enable very short dead times to provide lower open loop distortion, lowering the THD and overall losses. This reduces feedback, driving down T-IMD and DF to provide a step jump in the sonic quality of Class-D audio amplifiers and lowering overall losses.


http://epc-co.com/epc/Portals/0/epc/documents/briefs/AB003%20eGaN%20FETs%20for%20Class-D%20Audio.pdf

This paper from Infineon might also be worth taking a look at...
http://www.infineon.com/dgdl/Infineon+-+Application+Note+-+Power+MOSFETs+-+OptiMOS+200V+250V.pdf?fileId=db3a304344ae06150144b1d2f8250165


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## Babs

Yeah I saw that FB post and saw Steve's praise of them among a few others, though of course folks balked at the looks of it, which I couldn't care less. I'll be interested in what folks report on the GaN amp's abilities. Appears they'll be doing a 4-channel as well.


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## rton20s

Babs said:


> Yeah I saw that FB post and saw Steve's praise of them among a few others, though of course folks balked at the looks of it, which I couldn't care less. I'll be interested in what folks report on the GaN amp's abilities. Appears they'll be doing a 4-channel as well.


I saw the praise as well, but I really have to wonder if these things are really all that special? Or is this just hype? 

The closest thing out there in terms of similar power and class D is probably the Mosconi D2 150.2. From what I have seen those D2 amps are well received. I would imagine that the limited edition Soundigital GaN at $1500-$2000 would be a pretty significant premium over the D2 (not sure what retail is). Is there enough difference in this new amp tech to make it worth it? I'll maintain a healthy dose of skepticism until I see some independent reviews/tests/commentary.


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## Babs

Yep. Truth but verify. Agreed. 


Sent from iPhone using Tapatalk


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## rton20s

Babs said:


> Yep. Truth but verify. Agreed.
> 
> 
> Sent from iPhone using Tapatalk


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## gijoe

I read some of the information about GaN on Texas Instrument's site. I agree, these seem really interesting, but I'm skeptical as to whether or not they'll offer a practical improvement, as opposed to a theoretical one. Current class D amps are kicking ass fullrange, they offer great FR and low distortion. These chips may be better on paper, but I wonder if in the real world their advantages are going to matter.


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## chucko58

Not an amp pro, but I know just enough about electronics to be dangerous.

GaN FETs have a lower on-resistance and switch off faster and harder than silicon. For Class D amps, this has a bunch of benefits.

First, power losses are reduced (i.e. efficiency goes up). So you need less heat sink. And because the GaN FETs conduct electricity so much better than Si, the devices themselves are smaller. This means smaller amps that run cooler at the same or higher power levels.

GaN FETs switch much faster than Si. So you can increase switching frequency without losing too much efficiency. This in turn allows smaller inductors in the power supply, EMI, and output filters. It also allows the feedback loop and output filter to reduce their effect on the audio band, for better transient response and slew rate.

GaN is harder to manufacture than Si, but it uses a lot of the same techniques and equipment. Because the conductivity per unit area is so much better than Si, devices are smaller, and you can put more of them on a wafer. This should bring costs down pretty quickly as the chip factories gain experience. EPC is already offering (or claiming) GaN devices cheaper than the equivalent Si FETs.

GaN doesn't require a new design approach in the same way that MOSFETs did over bipolar transistors, or bipolars over tubes. But GaN makes _radically_ better power switching MOSFETs than silicon. The only real drawbacks are unfamiliarity and device prices, and the device costs are coming down pretty quickly.

I think in 15 years we'll be saying "Remember silicon MOSFETS?".


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## rton20s

Thanks for the response chucko. A lot of what you're stating is what I was picking up looking at EPC's website and videos. 

I guess the question for today is, do they warrant the significantly higher price tag over traditional MOSFET Class D amps? Either through a recognizable audible difference, increased efficiency, smaller footprint (via reduced heatink), etc.

It would be interesting to see how the Soundigital amp fared in a Richard Clark or similar bling listening test.


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## chucko58

rton20s said:


> I guess the question for today is, do they warrant the significantly higher price tag over traditional MOSFET Class D amps? Either through a recognizable audible difference, increased efficiency, smaller footprint (via reduced heatink), etc.


My opinion? Not today. The audible differences would be slight; maybe some golden-eared folks might find them worth the money.

The EPC amp is a demo piece. It's intended for electrical engineers, not for audioheads. A mass-produced board would be cheaper, even using current parts.

I think as GaN sees wider adoption in other areas (e.g. power supplies, where efficiency and power density in space and weight are big deals), mass production will bring device prices down, and we'll start to see some radically powerful and tiny amps at a modest premium or even a discount to current silicon Class D.


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## Victor_inox

rton20s said:


> I have no idea, but I would guess no. Just based on the claims of 90+% efficiency.


I developed and in the process of patent 1.2GHz switcher and it shows 96% efficiency.
i don`t have comment on soundsdigital amplifier. So far it seems nothing more than creative marketing.


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## Victor_inox

chucko58 said:


> Not an amp pro, but I know just enough about electronics to be dangerous.
> 
> GaN FETs have a lower on-resistance and switch off faster and harder than silicon. For Class D amps, this has a bunch of benefits.
> 
> First, power losses are reduced (i.e. efficiency goes up). So you need less heat sink. And because the GaN FETs conduct electricity so much better than Si, the devices themselves are smaller. This means smaller amps that run cooler at the same or higher power levels.
> 
> GaN FETs switch much faster than Si. So you can increase switching frequency without losing too much efficiency. This in turn allows smaller inductors in the power supply, EMI, and output filters. It also allows the feedback loop and output filter to reduce their effect on the audio band, for better transient response and slew rate.
> 
> GaN is harder to manufacture than Si, but it uses a lot of the same techniques and equipment. Because the conductivity per unit area is so much better than Si, devices are smaller, and you can put more of them on a wafer. This should bring costs down pretty quickly as the chip factories gain experience. EPC is already offering (or claiming) GaN devices cheaper than the equivalent Si FETs.
> 
> GaN doesn't require a new design approach in the same way that MOSFETs did over bipolar transistors, or bipolars over tubes. But GaN makes _radically_ better power switching MOSFETs than silicon. The only real drawbacks are unfamiliarity and device prices, and the device costs are coming down pretty quickly.
> 
> I think in 15 years we'll be saying "Remember silicon MOSFETS?".


 

what about GaAs or SiGe? 
what about organic developments?
Si mosfets are here to stay. 
And BTW unfamiliarity is a not a problem as supporting circultry is more similar than you it seems think.


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## rton20s

Victor_inox said:


> I developed and in the process of patent 1.2GHz switcher and it shows 96% efficiency.


So... Now you slap a cheap case on it, make a limited production run, send it out to some big names and slap a $2k price tag on it?


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## Victor_inox

Nope,slap decent case on it sell it on diyma for reasonable money and sell lisense to big names so they can charge you 2k.for those people to whom Victory Sonics is not good enough brand to buy. 
Story of my life.

Sent from my SAMSUNG-SM-G925A using Tapatalk


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## rton20s

Victor_inox said:


> Nope,slap decent case on it sell it on diyma for reasonable money and sell lisense to big names so they can charge you 2k.for those people to whom Victory Sonics is not good enough brand to buy.
> Story of my life.











(I couldn't bring myself to post One Direction.)


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## SounDigital

Hello Guys !

SounDigital GaN amplifier uses a IR/Infineon solution, it is a cascode configuration (GaN + Mosfet) to make a perfect device. There's no information on the market about IR GaN, few companies received access to use this GaN.

The advantage on GaN is the fast swiching, low RDS on, low Qrr, etc. It means that we can run in a higher frequency, (1Mhz on SD GaN), then the output low pass filter is smaller and the class D can reach a higher top end. The dead time is lower, improving the distortion and also the Qrr is zero. The THD at 1Khz at a half of the power is 0,002% and the S/N ratio is better than 100dB, there's no attenuation at 20Khz. Impressive numbers for a class D amp. The sound is very natural and free of ground noise.

The cost for low production is high yet, it is a numbered 200 units of a limited series. All new technology starts expensive and fall the price in mass production, we hope to sell this product cheaper in the future.

We have developed the GaN just to show the SounDigital technology in produce the first GaN based car amplifier ever. New comertial products are in development and I hope you can listen a SounDigital amplifier to prove that we are working hard to do the best.

Thank You !


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## Justin Zazzi

Thank you for visiting this thread and giving us the opportunity to ask you questions about your product. I have three:

Can you explain what Qrr is and how a lower value is beneficial?

What is this "dead time" you refer to, and why is a smaller value better?

Also, I heard there is no gain knob on the amplifier you put into production. What was the reason for this? Do you plan to include a gain knob on future products?


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## Victor_inox

Jazzi said:


> Thank you for visiting this thread and giving us the opportunity to ask you questions about your product. I have three:
> 
> Can you explain what Qrr is and how a lower value is beneficial?
> 
> What is this "dead time" you refer to, and why is a smaller value better?
> 
> Also, I heard there is no gain knob on the amplifier you put into production. What was the reason for this? Do you plan to include a gain knob on future products?


Why would you need a gain knob if you can match sensitivity with dsp output just perfect?

Sent from my SAMSUNG-SM-G925A using Tapatalk


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## High Resolution Audio

I'm very interested to learn more about this product. Hopefully, someone will get their hands on one and do a nice review here.


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## Justin Zazzi

Victor_inox said:


> Why would you need a gain knob if you can match sensitivity with dsp output just perfect?
> 
> Sent from my SAMSUNG-SM-G925A using Tapatalk


This reply keeps coming up whenever I ask this question and while it might work for a *very* tiny portion of the population who know exactly what they are doing, think about how many processes must change and how much new training is involved for the average person to do what you suggest.

1) Not everyone has a DSP or a source with an output voltage that can be limited from reaching some upper threshold. Even less people would know how properly to do what you're talking about. And no, simply not raising your volume past X amount does not count.

2) If you were to intentionally lower the output of your DSP or upstream device, you are also intentionally giving up the benefits of having a higher voltage line-level signal (increased resistance to induced noise). This is a step backwards technologically.

3) Your upstream gear is now hard limited because you must be able to meet the set input sensitivity of the amplifier. If your gear cannot output a signal with enough voltage to drive that amplifier to full power, there is absolutely nothing you can do about it.

4) Every piece of gear needs a way to adjust the gain structure with the gear it is connected to. The industry standard right now has the burden on the input section of the downstream gear called a "gain" knob. Why upset this standard so forcefully without reason?

5) By having no gain adjustment, you have now replaced a very straightforward procedure that can be done with a screwdriver in about a minute (turn up the gain knob until the clipping light turns on, then back it off a little bit) with a complex one that requires a DMM or oscilliscope and a laptop to interface with your DSP. The average consumer or installation shop doesn't have all of those tools, or doesn't know how to use them, or doesn't have enough time for such a thing.

If amplifiers without gain knobs were such a great idea, it would have caught on ages ago in multiple industries. That's not the case.


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## Justin Zazzi

I might be making a big deal about nothing. The specs on the website state input sensitivity is 0.5-6.0v. This conflicts with reports I've read that it has no adjustable input sensitivity. It would be nice to know one way or another. Or see a picture of the ends of the amplifier showing the controls available (or lack of).


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## Victor_inox

Jazzi said:


> I might be making a big deal about nothing. The specs on the website state input sensitivity is 0.5-6.0v. This conflicts with reports I've read that it has no adjustable input sensitivity. It would be nice to know one way or another. Or see a picture of the ends of the amplifier showing the controls available (or lack of).


 I see... Hopefully SounDigital will uncover that mystery.
variable sensitivity must have some kind of adjustment, maybe automatic. 
Many power amplifiers designed today has fixed sensitivity rating. 
most car audio amplifiers has built in preamp stage.


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## Babs

High Resolution Audio said:


> I'm very interested to learn more about this product. Hopefully, someone will get their hands on one and do a nice review here.



I volunteer. A head to head with a PDX V9 and F4. Just need one. Ears have heard pure class A. Ears have heard better A/B. Hit me up Soundigital.


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## Victor_inox

Babs said:


> I volunteer. A head to head with a PDX V9 and F4. Just need one. Ears have heard pure class A. Ears have heard better A/B. Hit me up Soundigital.


 That for sure qualified you as best tester.


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## SounDigital

Jazzi said:


> Thank you for visiting this thread and giving us the opportunity to ask you questions about your product. I have three:
> 
> Can you explain what Qrr is and how a lower value is beneficial?
> 
> What is this "dead time" you refer to, and why is a smaller value better?
> 
> Also, I heard there is no gain knob on the amplifier you put into production. What was the reason for this? Do you plan to include a gain knob on future products?


Qrr is a intrinsic parameter of the mosfet, Qrr increase the THD distortion and the EMI of the amplifier. The Qrr in a GaN is zero, but we use a cascode configuration and the Qrr is a litle bit more the zero, but too smaller than a mosfet, around 20 times Lower than a equivalent mosfet. We reached a 0,002% THD at 50% power.

Dead time is the necessary time between a mosfet turn off and another turn on. DT increase the THD distortion also. GaN is too much faster than a mosfet and the DT can be smaller because the turn off time is faster.

The reason to eliminate the gain adjust is to eliminate one opamp on the circuit, also, the potentiometer is a antenna to noise. The target application to GaN is a very good system and any medium class CD player can set the gain. To increase more the S/N ratio we added two shielded filters between the regulated power supply and another innovations. The result of the so many thing is a very, very quiet amplifier. It's one of the most impressive parameter os the SD GaN.

Thank you !


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## Justin Zazzi

Thank you for answering my questions. I have two more.

On your website the input sensitivity is listed as 0.5 - 6.0 vPP
Does that mean your amplifier will produce full power with a 2v input signal?

Also, you claim that not including a gain adjustment will reduce the noise of the amplifier. Did you build and measure a design with a gain adjustment to compare to the design without one? What was the result of that test? I am really interested to see how much of an improvement is possible.


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## SounDigital

Jazzi said:


> Thank you for answering my questions. I have two more.
> 
> On your website the input sensitivity is listed as 0.5 - 6.0 vPP
> Does that mean your amplifier will produce full power with a 2v input signal?
> 
> Also, you claim that not including a gain adjustment will reduce the noise of the amplifier. Did you build and measure a design with a gain adjustment to compare to the design without one? What was the result of that test? I am really interested to see how much of an improvement is possible.


The information about 0,5 - 6Vpp is wrong, the correct input sensitivity is 1,5 RMS fixed.

Any opamp, even the more quiet produce some noise, you can find the input noise on datasheet, the parameter is shown in (nV√Hz). When you add a opamp to set the gain and make some filter you are adding noise, more opamps, more noise. Also, a trimpot or a switch are antennas to capture noise. We prefer a more pure sound instead some functions on this product and we reach what we want. The background noise is perfect.

Thank you !


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## Victor_inox

SounDigital said:


> The information about 0,5 - 6Vpp is wrong, the correct input sensitivity is 1,5 RMS fixed.
> 
> Any opamp, even the more quiet produce some noise, you can find the input noise on datasheet, the parameter is shown in (nV√Hz). When you add a opamp to set the gain and make some filter you are adding noise, more opamps, more noise. Also, a trimpot or a switch are antennas to capture noise. We prefer a more pure sound instead some functions on this product and we reach what we want. The background noise is perfect.
> 
> Thank you !


 Here we go 1.5V just like biketronics (Hypex)and just about any pro-audio power amplifier on the market. perfect for typical line out of car audio HU (despite inflated ratings of 5 or 6V.)


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## AccordUno

Okay, I can say the amps are interesting.. I took a listen to Steve Cook's Avalanche. The amp is transparent, kinda weird to explain it but definitely something I'm looking more into..


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## Babs

AccordUno said:


> Okay, I can say the amps are interesting.. I took a listen to Steve Cook's Avalanche. The amp is transparent, kinda weird to explain it but definitely something I'm looking more into..



The amp was running midbass wasn't it?


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## AccordUno

He told me it was on his midrange.. He's running a Beyma midrange and I need to see how low it gts but, but, I'm intrigued now.. 

And no, I'm not saying this because I'm associated with Beyma or with the Importer of Soundigital Amps.. I'm saying this as my honest opinion, I'm already using Soundigital amps in my car and they sound good, but this amp takes it up a level..


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## Babs

Well any and all newcomers with a quality product or new innovation to the US market I'm always a fan. 


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## SkizeR

i really need to ask... how does someone sit in a car, take a listen and think "yeah, these amps sound transparent"..?


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## rton20s

SkizeR said:


> i really need to ask... how does someone sit in a car, take a listen and think "yeah, these amps sound transparent"..?


Duh...


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## SkizeR

rton20s said:


> Duh...


oh..


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## knever3

Meade did a review on these 5 years ago...

https://www.youtube.com/watch?v=Y1rZ9v7Dp4I

We are just seeing a thread about them now?


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## rton20s

knever3 said:


> Meade did a review on these 5 years ago...
> 
> https://www.youtube.com/watch?v=Y1rZ9v7Dp4I
> 
> We are just seeing a thread about them now?


Nope. Completely different amp. Try to keep up. Start with the OP.


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## jtaudioacc

rton20s said:


> Duh...


niiick is such a newb. :laugh:


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## AccordUno

SkizeR said:


> i really need to ask... how does someone sit in a car, take a listen and think "yeah, these amps sound transparent"..?


I've heard his truck before with what he had and what he has now, so I have a mental picture of both. when I said I can't explain it, I meant it, so I used words that are common: transparent (probably because it has no onboard circuits to muddle the sound), I would say more dynamic..

Still can't explain it, I can only suggest that you take a listen and base your opinion off that and not follow mine.


BTW, that amp is not it and what replaced that is not like that either..


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## SkizeR

AccordUno said:


> I've heard his truck before with what he had and what he has now, so I have a mental picture of both. when I said I can't explain it, I meant it, so I used words that are common: transparent (probably because it has no onboard circuits to muddle the sound), I would say more dynamic..
> 
> Still can't explain it, I can only suggest that you take a listen and base your opinion off that and not follow mine.


id love to listen to his car. if only his wasnt 1000 miles away :/

also, dont forget different speakers and different tunes. the guy swaps equipment like a mad man lol


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## AccordUno

I believe he was using the Beyma mids at SBN as well.


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## bassfromspace

Accord.....which Soundigital's do you currently have ?


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## AccordUno

I have the 800.4 from that line clear top w/ fans and then 2 - 400.4 from the evo line. I'm planning on having 2 of the gan amps for meca finals. Working in qualifying so i can redo my install. 

Break down: 400.4 are bridged for the mids and tweeters (200w per speaker), 800.4 runs the 8" mid bass and 10" subs, both getting 200w a piece.

The evo line is no slouch either.. holding up pretty well.


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## AccordUno

Time to bring this back up, here are the manufacturer numbers during testing. They are still in the box, while I work thru my install.


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## SounDigital USA

Any questions you may have about our GAN amplifiers, please let me know.


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## envisionelec

I'd never heard of them (unsurprising since I've been out of audio design for a couple years), but heard a pair of them in TSmith's Sequoia at the recent TN-KY 2016 get-together. But let me back up. I have never seen or heard any Soundigital products and had only known them as the plastic, single board amps.
When I peered into the back of Tim's truck, I saw a pair of Brax "whatevers" (sorry...didn't catch the model). I assumed they were a high biased Class A/B based on the heat they were dissipating at idle - and I assumed they were driving the front stage. I also assumed the Soundigital were on the subwoofer. But I was confused as this was a high end build and SD is not high end (IMO).

So I listened and thought - these are some great sounding amps. I'm of the opinion that amplifiers can sound different but only in non-quantifiable ways that can't necessarily be proven with test equipment. This is a broad departure of my thoughts from days past, but I digress...it's just a personal expression of opinion. :blush:

So when I got out to chat with Tim, he informs me that these ugly SD amps are running the front stage. You could have knocked me over with a feather! I wasn't about to backtrack because I know what I heard (and I know what I *didn't* hear which is the not-wonderful S/N ratio of most "car" Class D amps) - so of course I was interested. He tells me that he's amazed when opening one up - that there's "nothing" in there; no MosFETs, big filter caps or toroid. When I brought up a "guts" photo online, I mentioned to Tim that it probably doesn't need big capacitors or transformer or output inductors because it's probably running a 1MHz carrier. I also suspected that the MosFETs were soldered to the bottom of the PCB which, by, now, is confirmed based on the package types used. 

Now, I think it's complete BS that they should sell for $1200. For that money, they shouldn't look like Walmart VR3 amp. They're not using the dev board, so I'm not sure what could be the reasoning except to set it apart from every other Class D amp out there.

BTW, it's still Class D - it's just a much improved MosFET they're using. There's only so much time in the world and I'm not going to be spending much time on researching this unless someone wants to build a competing product - then I'm your engineer.


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## Huckleberry Sound

mmmmmmmmmmmmm


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## AccordUno

So did you like them? Sounded like you did, just not a fan of the look and feel? I think that part is getting addressed and 4 channel version is coming.


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## envisionelec

AccordUno said:


> So did you like them? Sounded like you did, just not a fan of the look and feel? I think that part is getting addressed and 4 channel version is coming.


Just the look. It was Tim that commented on that. I said I couldn't figure out what they were at first glance and when I looked again, I thought they could have used a better enclosure design.

Yes - maybe I wasn't clear.  I loved the sound. The noise floor (hiss, buzz, "sparkle" (something class D amps do because of their zero PSRR) was non-existent. 

I want to build one to see what they're all about because the numbers from an engineering perspective are fascinating.


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## AccordUno

Nope, you were clear about the sound and the look of amp. The look has bring brought up and I'm hoping that it's being address. As for me I kinda like it, visually it might not appeal to some, but the meat and potatoes of it, is really what it does that sold me..


BTW, I meant to talk to you at the GTG, sorry, I didn't ask for who was who while I was there.. I have some amps I need to talk to you about, some old school SS Ref amps that I want to move and need a little TLC first..


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## envisionelec

AccordUno said:


> Nope, you were clear about the sound and the look of amp. The look has bring brought up and I'm hoping that it's being address. As for me I kinda like it, visually it might not appeal to some, but the meat and potatoes of it, is really what it does that sold me..
> 
> 
> BTW, I meant to talk to you at the GTG, sorry, I didn't ask for who was who while I was there.. I have some amps I need to talk to you about, some old school SS Ref amps that I want to move and need a little TLC first..


No problem. I was tired from the night before and wasn't as sociable as I usually am. I was trying to catch up and listen to a few vehicles but was completely unfamiliar with who was driving what - out of the loop and felt like I didn't have much to contribute. 

I'm not really working on amps these days. It's basically by invitation. Send me a PM and I'll let you know what kind of timeline you'd be looking at.


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## fury

So...
Are there any other amplifiers on the market now using GaN FET?
Are they suitable for use in class AB amplifiers too?

If not, why hasn't the market adopted these?
The efficiency gains seem fantastic for in-car use.


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## rton20s

Nothing really new yet from what I have seen. Give it about two months, we may start seeing some new amplifiers using GaN FETs. No inside knowledge. This is based solely on the fact that CES 2018 is two months out. How much of anything shown off at CES actually makes it to market and when is a whole other conversation.


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## jtaudioacc

rton20s said:


> Nothing really new yet from what I have seen. Give it about two months, we may start seeing some new amplifiers using GaN FETs. No inside knowledge. This is based solely on the fact that CES 2018 is two months out. How much of anything shown off at CES actually makes it to market and when is a whole other conversation.


they had a pretty large booth at SEMA. it seemed only focused on loud.


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## rton20s

jtaudioacc said:


> they had a pretty large booth at SEMA. it seemed only focused on loud.


I was talking about GaN FET based amplifiers in general, but your statement about SounDigital doesn't surprise me in the least.


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## Babs

I know of one other individual who’s been working on a GaN design but just in the stages of “it powered up but didn’t explode so that’s progress”. 

Hopefully some more amp-builders will explore GaN. Not to slight SoundDigital at all though this may sound like it.. But if an SPL-oriented company can put together a strong two channel that was a hole-in-one as a big-power SQ amp, it says something for GaN as a platform. Big buying power by someone getting in and actually investing in GaN for production will be the determiner if GaN gets off the ground. 


Sent from my iPhone using Tapatalk Pro


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## lostthumb

Sound Digital is working on a new version of the GAN based amplifier and it should be out soon. They are hoping in the next 30 days? Their chassis is being re designed. I hear there might be a 4 channel and 6 channel variation as well. They will be more affordable than the previous one.


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## pocket5s

I know of one other company that has a multi-channel design in the works. Assuming it isn't the same one Babs mentioned (I doubt it, but never know), then that makes 3.

I too heard SD was bringing theirs back, at a much reduced price as well.


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## SkizeR

Babs said:


> I know of one other individual who’s been working on a GaN design but just in the stages of “it powered up but didn’t explode so that’s progress”.
> 
> Hopefully some more amp-builders will explore GaN. Not to slight SoundDigital at all though this may sound like it.. But if an SPL-oriented company can put together a strong two channel that was a hole-in-one as a big-power SQ amp, it says something for GaN as a platform. Big buying power by someone getting in and actually investing in GaN for production will be the determiner if GaN gets off the ground.
> 
> 
> Sent from my iPhone using Tapatalk Pro


Mike's has been up and playing. Just doesn't have a case

Sent from my SM-G950U1 using Tapatalk


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## geartech

Found an interesting paper on GaN technology in D-class amplification

http://epc-co.com/epc/Portals/0/epc/documents/briefs/AB003 eGaN FETs for Class-D Audio.pdf

Did a check and DigiKey has GaN amp development modules but at $1300.00 per module its a little pricey

https://www.digikey.com/products/en? WT.z_cid=sp_917_0110_buynow&site=us&lang=en&mpart=EPC9106


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## forty5cal1911

geartech said:


> Found an interesting paper on GaN technology in D-class amplification
> 
> http://epc-co.com/epc/Portals/0/epc/documents/briefs/AB003 eGaN FETs for Class-D Audio.pdf
> 
> Did a check and DigiKey has GaN amp development modules but at $1300.00 per module its a little pricey
> 
> https://www.digikey.com/products/en? WT.z_cid=sp_917_0110_buynow&site=us&lang=en&mpart=EPC9106


Yeah I looked at those a while ago. Was very interested in getting one of the eval boards but just a bit too pricey. Also, looked into a couple of the other board kits that required building off of their design. Still pricey and quite involved.

Would love to hear from anybody who may have played with these or at least heard one.


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## DeltaB

forty5cal1911 said:


> Yeah I looked at those a while ago. Was very interested in getting one of the eval boards but just a bit too pricey. Also, looked into a couple of the other board kits that required building off of their design. Still pricey and quite involved.
> 
> Would love to hear from anybody who may have played with these or at least heard one.


Major manufacturers are already using Class D GaN-FET in their amps in the commercial home audio market. You can listen to the new Pioneer Elite models at your local audio outlet like BestBuy.


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## rton20s

geartech said:


> Found an interesting paper on GaN technology in D-class amplification
> 
> http://epc-co.com/epc/Portals/0/epc/documents/briefs/AB003 eGaN FETs for Class-D Audio.pdf
> 
> Did a check and DigiKey has GaN amp development modules but at $1300.00 per module its a little pricey
> 
> https://www.digikey.com/products/en? WT.z_cid=sp_917_0110_buynow&site=us&lang=en&mpart=EPC9106


Did you even look at the first post of the thread?


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## Babs

DeltaB said:


> Major manufacturers are already using Class D GaN-FET in their amps in the commercial home audio market. You can listen to the new Pioneer Elite models at your local audio outlet like BestBuy.


Yeah I predict only if GaN takes off, it'll be 3-5 years for car amps to really become viable commercially as a hifi alternative. Simply due to cost.


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## AccordUno

Got disconnected for a while. About SD and their focus on Loud. SD is not just pushing to the US, they are international and they have different focuses in different countries. Last time I checked they have released a newer SPL amp, hopefully more folks will look at the other lines that they offer, not all are SPL specific.


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## fury

Planning amplifiers for my new car which has some space constraints, and wondering what the arguably best sounding GaN FET amps currently are then?
They seem to fit a fantastic size/power envelope with good sound quality attributes.
Are the SD 300.2D's the pick?
I'll need enough channels for 3way + sub...


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## rton20s

fury said:


> Planning amplifiers for my new car which has some space constraints, and wondering what the arguably best sounding GaN FET amps currently are then?
> They seem to fit a fantastic size/power envelope with good sound quality attributes.
> Are the SD 300.2D's the pick?
> I'll need enough channels for 3way + sub...


As far as I know Soundigital is the only company, so far, to bring a GaN FET based amplifier to the commercial car audio market. There are others under development from what I have read, but not available. I think even the SounDigital SD300.2D are pretty hard to come by.


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## PPI_GUY

Just wanted to resurrect this thread. JL Audio is debuting a new amplifier line this coming weekend at KnowledgeFest in Indy and I am wondering if they will be using a GaN FET based design? Manville Smith alluded to this new amplifier series debut in another thread here a few days ago but of course couldn't elaborate. 
It may only be a DSP incorporated into the design or something less exciting but, I am very hopeful it will be the first mainstream iteration of GaN FET.


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## thehatedguy

No, it's not.

I've seen the v2 HD amps though.


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## bnae38

Bump.

Nothing new?


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## rton20s

bnae38 said:


> Bump.
> 
> Nothing new?


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## tonynca

I emailed Soundigital today and got this response:

We are working on new model but no ETA atm.

We do still have the GAN 300.2 limited edition model available.

Best regards,
Diogo Ianaconi
CEO
HKI SounDigtal USA

I just wish there was a 4 channel variant. The tech sounds promising. 


Sent from my iPhone using Tapatalk


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## bnae38

Bump!

Any news?


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## Bnlcmbcar

This home audio amp takes 56V but will also work from 48V to 60V.

Maybe figure out a way or find a audiophile grade power supply to convert 12-14v to the 56v and you’ll possibly have a nice car audio amp with 2 ch of GaNFET..
















2 x BOSC Monoblock










Orchard Audio Launches Kickstarter Campaign for BOSC Monoblock GaN Audio Amplifier


There is a very interesting new audio project being promoted on Kickstarter. Coming from Orchard Audio, the BOSC is a well engineered hi-fi monoblock audio amplifier that explores the latest gallium nitride (GaN) semiconductor technology to achieve ultra-high performance in a small package. This...




audioxpress.com


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## Ge0

chucko58 said:


> Not an amp pro, but I know just enough about electronics to be dangerous.
> 
> GaN FETs have a lower on-resistance and switch off faster and harder than silicon. For Class D amps, this has a bunch of benefits.
> 
> First, power losses are reduced (i.e. efficiency goes up). So you need less heat sink. And because the GaN FETs conduct electricity so much better than Si, the devices themselves are smaller. This means smaller amps that run cooler at the same or higher power levels.
> 
> GaN FETs switch much faster than Si. So you can increase switching frequency without losing too much efficiency. This in turn allows smaller inductors in the power supply, EMI, and output filters. It also allows the feedback loop and output filter to reduce their effect on the audio band, for better transient response and slew rate.
> 
> GaN is harder to manufacture than Si, but it uses a lot of the same techniques and equipment. Because the conductivity per unit area is so much better than Si, devices are smaller, and you can put more of them on a wafer. This should bring costs down pretty quickly as the chip factories gain experience. EPC is already offering (or claiming) GaN devices cheaper than the equivalent Si FETs.
> 
> GaN doesn't require a new design approach in the same way that MOSFETs did over bipolar transistors, or bipolars over tubes. But GaN makes _radically_ better power switching MOSFETs than silicon. The only real drawbacks are unfamiliarity and device prices, and the device costs are coming down pretty quickly.
> 
> I think in 15 years we'll be saying "Remember silicon MOSFETS?".


Exactly. I was going to chime in here but you have it covered.

GaN FETS are a newer technology to the consumer market. However, they have used in extremely high current and high voltage inverters for electric car motors. Power levels are over 20x what is typically used in a car amp. It is a huge cost saver if you can make your automotive inverter and heat sink package smaller. Well, the same trickle down theory applies to amplifiers. We already have some pretty small amps with decent power density ratios. Now imagine making that amp 30% smaller. You package envelope is now set by the size of the external I/O connectors and maybe a few larger DSP chips inside the package. I think this tech is pretty damn cool.

Ge0


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## Ge0

Victor_inox said:


> I developed and in the process of patent 1.2GHz switcher and it shows 96% efficiency.
> i don`t have comment on soundsdigital amplifier. So far it seems nothing more than creative marketing.


Multi-phase switcher? I always wondered why car amps never went that route. Something the computer and automotive industry use on a regular basis.

Ge0


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## bnae38

I don't really care about them being smaller tbh.. though that is nice.

I am extremely excited about near or better than class A linearity while producing almost no heat! That is very cool imo, I would love to get one on the bench and see what it can do on the analyzer .


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## Ge0

chucko58 said:


> My opinion? Not today. The audible differences would be slight; maybe some golden-eared folks might find them worth the money.
> 
> The EPC amp is a demo piece. It's intended for electrical engineers, not for audioheads. A mass-produced board would be cheaper, even using current parts.
> 
> I think as GaN sees wider adoption in other areas (e.g. power supplies, where efficiency and power density in space and weight are big deals), mass production will bring device prices down, and we'll start to see some radically powerful and tiny amps at a modest premium or even a discount to current silicon Class D.


Exactly again. Mass manufacturing will drive GaN prices down significantly. I use a lot of MOSFETs in my designs. Modulated motor controllers, fuel injector drivers, etc. 10 years ago I would pay $0.43 for a 20mohm FET in 20 million piece quantities. With recent advancement in FET technology I can now buy a 1.5mohm FET for $0.11ea in 10 million piece quantities. Oh, and by the way, package sizes have shrunk significantly as well. No more D2Packs!!!

Ge0


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## bnae38

Bump?

I've heard rumblings of soundigital coming out with more gan amplifiers, but sadly I have yet to hear of anything.

I have some bosc raw pcbs I should really populate someday but yikes on the parts costs.. would love to run a gan amp on the dScope some day .


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## lpreston

bnae38 said:


> Bump?
> 
> I've heard rumblings of soundigital coming out with more gan amplifiers, but sadly I have yet to hear of anything.
> 
> I have some bosc raw pcbs I should really populate someday but yikes on the parts costs.. would love to run a gan amp on the dScope some day .


I inquired, and the reply was 'Yea but was put on hold for some time'


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## lpreston

Bnlcmbcar said:


> This home audio amp takes 56V but will also work from 48V to 60V.
> 
> Maybe figure out a way or find a audiophile grade power supply to convert 12-14v to the 56v and you’ll possibly have a nice car audio amp with 2 ch of GaNFET..
> View attachment 269121
> 
> View attachment 269123
> 
> 2 x BOSC Monoblock
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Orchard Audio Launches Kickstarter Campaign for BOSC Monoblock GaN Audio Amplifier
> 
> 
> There is a very interesting new audio project being promoted on Kickstarter. Coming from Orchard Audio, the BOSC is a well engineered hi-fi monoblock audio amplifier that explores the latest gallium nitride (GaN) semiconductor technology to achieve ultra-high performance in a small package. This...
> 
> 
> 
> 
> audioxpress.com


You realize those are $1600 for a pair of monoblocks?


----------

