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GaN Systems Amplifier Eval Board Measurements

Matias

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VintageFlanker

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NYfan2

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What I understand from the interview that the intellectual people podcast had with Bruno Putzeys (https://www.audiosciencereview.com/...ellectual-people-podcast-bruno-putzeys.24138/) is that Bruno Putzeys doesn't see much improvement for the Purifi Audio products by switching to Gallium Nitride, he states that the use of Gallium Nitride don't improve (much) the current product. He expects more from Silicon Carbide MosFets in the future, especially for high power amplification (he mentions 10kW).

So Purifi won't (probably) use GaN in their amplifiers, it will be interesting to see if other manufacturers will switch to GaN and if they can produce amplifiers with higher Sinad that can compete with Ncore and Purifi.
 

restorer-john

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is that Bruno Putzeys doesn't see much improvement for the Purifi Audio products by switching to Gallium Nitride, he states that the use of Gallium Nitride don't improve (much) the current product.

It's all about cost versus performace. They are using cheap automotive purpose and designed MOSFETs, whereas Gallium Nitride is expensive new tech.

Once the cost per device drops, they will be all over it, proclaiming it's the best thing since sliced bread.
 

restorer-john

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@amirm You said, "Let's start with analog:". Did you pursue any testing with the digital side/inputs or was it an utter disaster?
 

PeteL

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High feedback amplifiers are difficult to design and keep stable.
Yes to an extent, but when I am looking at the board up top, heck this looks nothing like a simple design. What am I missing there what are all these component doing? Does this really make it easier to design high performance class D?
 

orchardaudio

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orchardaudio

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Orchard Audio has GaN-based amps. They seem to be performing exceptionally well. He's a member here (@orchardaudio), so can probably comment :cool:

Manufacturer eval boards are not meant to be used this way. They are designed to showcase the technology in this case particularly the efficiency of GaN Fets which this eval board achieves.

It is always up the designers to tweak it and make it better for their purposes.

These are mass produced and will not focus on audio performance. They will not be using the best quality parts because that would make them to expensive. My amps use 0.05% and 0.1% thin film low noise resistors for example, you will never see this on an evaluation board.
 

VintageFlanker

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voodooless

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They will not be using the best quality parts because that would make them to expensive

The thing is still expensive.. € 735,- for just the amp ;) But that's the way it goes with eval kits.. You always pay a missive premium.
 

pma

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The amp looks promising except for the high noise. Do we have an idea why it is quite noisy, is it an input stage?
 

gonzoucab

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Is this topping monoblock design?


when?
 

pma

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I don't think I have ever tested a switching amplifier with this level of frequency independence. Even Class AB linear amps struggle to produce such an absolutely clean response. Amplifiers with high amount of feedback run out of gain at higher frequencies and hence distort more. Not this design.

Yes nice at first view at plots, but still too high absolute numbers. -65dB/100W/@45kHzBW is really nothing to call home about. It should have been 15 - 20dB better to be called "clean".
 

IVX

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hah, feedback loop arrangement is a much more intellectual and effective thing than just using the new MOSFETs. B. Putzeys class D amps will win that evaluation board for THD+N, SNR, and other audio-related specs even being implemented on 1990x MOSFETs ;) Only the efficiency get some profit, is anyone feels that silicon class D amps are too hot?
 

Bear123

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I think that is a bit of a different line of thinking. For sure, there is no immediate reason to replace a perfectly fine working AB amp :). SINAD difference is about 10dB to the best Class D’s though. I doubt a GaN amplifier will add another 10 dB.
Wow, those NAD amps look really nice! Great power and excellent measured performance. I can see why you feel no need to switch to a class D design.
 
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