GaN Class-D feature packed amplifier from GaN USA themselves limited supply!!!

Any buyer should be aware that since this board is meant for evaluation, it cannot sustain full power into 4 ohms since it has no heatsinks. For that reason its paired with a Switch Mode Power Supply that limits its 4 ohm power to 114 watts.


There is an extensive review of this product on audioscience.com: https://www.audiosciencereview.com/forum/index.php?threads/gan-systems-amplifier-eval-board-measurem...

You can see the power measurements there.


This is an excellent platform for seeing what GaNFETs can do. But as an audio amp for high end audio use you are probably better off looking elsewhere, although I can see the price being attractive. Apparently Amirm (the reviewer) felt that way too- pay attention to his conclusion at the end of his review.


But if your interest is building a class D amplifier, you might want to look into  https://www.classdaudio.com/
They sell more powerful modules and for a lot less money, although their modules cannot accept a digital input (nor are they GaNFET). You can then get a SMPS from https://connexelectronic.com/ and hook them up. Pay attention to the specs so that the power supply you get will work with the module you choose.

Then there are these:
https://orchardaudio.com/shop/ols/products/bosc-amplifier-module

and these:
https://orchardaudio.com/shop/ols/products/strk-ltr-mdl

The thread derailers are out yet again.

Ok I’ll bite, let see what your Class-D can do tested by Amirm,
and if it can maintain full power into 4ohm continuously when it comes.



For those that wish to know these are the specs from Gan themselves, on this Class-D

Evaluation Board Test and Validation
The initial Evaluation Boards were tested and validated using industry-standard measurements, with recognized techniques and equipment. The standard set of industry performance and validation tests were run using this Test Bench. Performance Specification Testing
Power Output (200W into 8 ohms)
Power Output (400W into 4 ohms)

Following are the results of both the initial Characterization that was performed on the Class-D Amplifier platforms. Unless otherwise noted, the Characterization was performed under the Power Supply conditions that allow for the specified Target Market specification of 200W/8-ohms. This requirement resulted in Power Supply Voltage rails of +/-32VDC. This selected Power Supply definition provides up to 200W of clean power into 8 ohms, (as captured in Figure 5.1 below).

Figure 5.1 https://ibb.co/Jm9vbG5 with user switchable low or high feedback
The owner gave it to Amirm for testing set at low, high would have measured far better in the tests.

Amirm: "his focus was to keep the level of feedback low to show the advantage of the GaN transistors not needing much. He was not aiming to produce the best performance possible. Personally I wish he had targeted that, given that is what we like to see here."

And yes one thing the detractors got correct, more power can be obtained with added heatsinks and a higher voltage smp later if an owner needed more (I believe this has more than enough).

But I’ll still say like any Class-D, it/they are not for the 0.9ohm EPDR load that Wilson Alexia’s and others present especially in the bass.

Also they still need what Technics did with their SE-R1, and raise the switching frequency from 600khz to 1.5mhz so the output filter can do it’s job of filtering it out so this sort of 70 degrees of phase shift is not in the audio band. https://ibb.co/LpMkm8Y

Cheers George

@georgehifi  So far as I can make out no-one is being a detractor. Just simply stating fact.


Your original thread included a link to Amirm's review. He does not attack it either; instead as I have pointed out, substantiated the idea that its excellent for its intended purpose, which is to demo and evaluate what the GaNFETs are capable of. This isn't a bad thing. Its simply a thing.


As the unit sits, if you were to drive Alexia's with it I think you might be surprised how well it could do with that load until its SMPS limits its current. A set of heatsinks could fix that. Here's the manual: https://gansystems.com/wp-content/uploads/2020/03/GaN-Systems-Class-D-Amplifier-and-SMPS-EVB-User-Gu...It suggests that the amp can support 400 watts/4 ohms if heatsinks are employed. But in the little time I had to peruse the manual I didn't find how they suggest the heatsinks be applied. The point I'm making here is that since this amp employs GaNFET output devices, its output impedance will be only a few milliohms even in the zero feedback mode. This will mean that as long as the amp is not being overloaded, it will behave as a voltage source into the 0.9 ohms of the Alexia. I'm not saying it will play to full power- that will depend on heatsinks and the power supply used (which won't be the one in the kit).


That 0.9 ohm load only shows at a very narrow range of frequencies in the Alexia, so I really doubt its a problem. Wilson themselves claim its not, so to maintain your position you'll be up against them.