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Infineon CoolGaN Class D amplifier EVAL_AUDAMP24 vs Purifi?

hombre

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I received the Infineon CoolGaN Class D amplifier EVAL_AUDAMP24 evaluation module GaN today. Will be powering with generic PSU +/- 50V. Many built in protection features built in the evaluation board.

20201111_130342.jpgFrom the brochure:

"The EVAL_AUDAMP24 GaN e-mode High Electron Mobility Transistor (HEMT) evaluation board is a two-channel, 225 W/ch (4 Ω at ±43 V) or 250 W/ch (8 Ω at ±63 V) half-bridge class D audio power amplifier for Hi-Fi audio systems. This evaluation board demonstrates how to use the CoolGaN™ gallium nitride transistor, IRS20957S controller IC, implement protection circuits, and design an optimum PCB layout using the IGT40R070D1 E8220, CoolGaN™ gallium nitride transistor. The reference design provides all the required housekeeping power supplies for ease of use. The two-channel design is scalable for power and the number of channels. "
 
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hombre

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Quick report after only a few minutes of testing:

Playing the EVAL_AUDAMP24 through sensitive BG NEO 10 planar midrange:

No turn on Pop / Click.
Only a faint turn off click.
No audible hiss, hum, buzz at idle / no signal input
Very clear when playing music.

I will be comparing the Infineon EVAL_AUDAMP24 to my Texas Instruments TPA3255 amps, which in my opinion are very good / excellent particularly when powered by linear power supplies.
 

daniboun

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Hi
Very interesting. I would be very curious to see how it performs vs the top end TPA3255 by Drmordor and VS a Purifi module
 

Matias

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Interesting indeed. This makes it around SINAD 85 in 4 ohms 5W by the way.
Found it on Mouser for about 550 usd.

Manual here.

Ranking here.

Infineon EVAL_AUDAMP24.jpg
 

daniboun

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Last Jlester TPA3255 with PFFB with Coilcraft VER2923-103KL flat wire peforms very well :

8R+5W.png

7ED2BA27-E882-4C65-AB61-B0E555D8DB37.png
 

daniboun

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Interesting indeed. This makes it around SINAD 85 in 4 ohms 5W by the way.
Found it on Mouser for about 550 usd.

Manual here.

Ranking here.

Found it @ 395 euros = $467

I saw that the Gan Bosc Modules perform the following :
  • SINAD @ 5W 1kHz: 105dB into 4Ω
As per Ranking it is very close to the Benchmark AHB2 ) For a very best price ;)
 

Matias

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As per Ranking it is very close to the Benchmark AHB2 ) For a very best price ;)

And the Purifi is even better measuring for similar price as I summarized here.
 

daniboun

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EB1000

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GaN based class-d, such as the above, will give you nothing, unless you take the full advantage of the GaN FET by operating the amp at much higher switching frequency in the MHz range. But due to lack of high frequency GaN drivers, this amp is operated at 500kHz, which does not give it any advantage over MOSFET based amps. 99% of what the manufacturer says is BS...
 

daniboun

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GaN based class-d, such as the above, will give you nothing, unless you take the full advantage of the GaN FET by operating the amp at much higher switching frequency in the MHz range. But due to lack of high frequency GaN drivers, this amp is operated at 500kHz, which does not give it any advantage over MOSFET based amps. 99% of what the manufacturer says is BS...

I guess you refer to the EVAL_AUDAMP24 ?
 

daniboun

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Not bad, but this is where these chips shine. Do you have an IMD 18.5 + 19.5 kHz kHz?

Unfortunately not, you need to ask Jlester for further test. (measurements performed by Quantasylum.com using their QA401 device. )
These informations are extracted from his site.

for a $100 module, seems crazy )
 

Matias

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Also no high frequency THD+N is shown. Usually ICEpower, Pascal, Hypex and Purifi show Power x THD+N for 100 Hz, 1 kHz and 6.67 kHz. Here we see from Infineon only 1 kHz. Usually 6.67 kHz is where Hypex nCore and Purifi Eigentakt have their advantage.
 

daniboun

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As per last update I share what has been said by Jlester for his new TPA3255 module :

"My QA400 is limited that's why I'm planning to upgrade to QA401, QA400 measurement is 0.0025% THD+N and 0.00089% THD
This is definitely better than XRK build in terms of THD performance.
I'm also planning to send a fully built amplifier to Amir for review. (If he accepts it)
My target is 95-96dB SINAD using 36V PFFB config. "

Seems a real bargain ) Let s wait for ASR review );)
 

daniboun

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Also no high frequency THD+N is shown. Usually ICEpower, Pascal, Hypex and Purifi show Power x THD+N for 100 Hz, 1 kHz and 6.67 kHz. Here we see from Infineon only 1 kHz. Usually 6.67 kHz is where Hypex nCore and Purifi Eigentakt have their advantage.

I did not measure my TPA3255 by DrMordor but something is sure : it brings all my Hypex Ncore amps + Pascal double Mono to their knees, I am not exaggerating !
Seems that the Combo TPA3255 + OP amps MC33272 is just amazing ! I own many many amps (see my reviews on DIY Audio) but I am in love with Drmordor modules ) Best Soundstage for ever !

I should test soon the new GaN amplifier with SinchroRec LLC PSU, sounds promising ) Loop gain would be about 75-85db at least as good as the Purifi.

 
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hombre

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Here is my Infineon EVAL_AUDAMP24 + power supply setup - still in original factory box! :D.

I am using a 500Watt PSU +/- 45V (that rating is based on 110VAC, I have about 121VAC so getting +/-50V DC). This PSU also has +/- 15VDC and +12VDC in case I want to run some other circuits. I have a +/-70V PSU on order. One only needs the plus, minus and ground output from a +/- 38 to +/- 75 VDC power supply to drive the EVAL_AUDAMP24 so setup very easy. This will get you a taste of GaN for under $600.

Upon more careful listening, there is very faint power On / power Off pop click. At idle I can hear a faint hiss with my sensitive ear when it is within 2 inches to 95dB sensitive tweeter. The curious thing is it sounds less like a monotonous hiss but more like aliens telegraphing something - spooky action at a distance not of the quantum entanglement type. LoL. Anyhow the TI TPA3255 evaluation unit may be quieter at idle but both amps approach being dead quiet. Not really a fair comparison as I am using a linear power supply for the TI TPA3255. Music listening is sounding quite good...hopefully in the future I can figure out a way to quickly pop in my Sony TAA-1ES Class A /AB amp for comparison.
InfineonGaN Amp1.jpg
 

daniboun

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Thanks for sharing )
As said by EB1000 I am not convinced that this "hybrid" Class D / GaN take advantage of the GaN FET technology.
For such a budget or bit more I would go for the bulk Bosc modules version with full GaN profits.
 

kipman725

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I'm waiting for the (high power) amp with GaN Systems devices:
https://gansystems.com/
Best GaN fets I have used, great packaging (needed for high frequency switching). I Have run upto 27 MHz in soft switched applications. Its been a few years but I think I got Ton/Toff around 1nS on a clamped inductive test fixture.
 
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hombre

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Thanks for sharing )
As said by EB1000 I am not convinced that this "hybrid" Class D / GaN take advantage of the GaN FET technology.
For such a budget or bit more I would go for the bulk Bosc modules version with full GaN profits.

Perhaps I can consider that in the future. I am working on servo circuit so want the added protection, the high gain (33 dB) and ability to bypass the preamp that the Eval24 offers.

Could anyone tell me what J8 - DC protection does / how to use it on the Eval_AudAmp24? Is it separate or redundant DC speaker protection?
 

ZestClub

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The "hybrid" Class D / GaN seems like the way to go if the frequencies are high enough to take advantage of the Gan's.
 
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