GaN FET Amps vs. Traditional Class D Amps

You’ll never see a GaNFET go toe to toe with high end Class D amps like Eigentakt’s or the best NCores let alone a Mola Mola. I dare anyone to A/B these. The only claim to fame I ever here is "GanFET technology offers several advantages over ’traditional’ Class D amplifiers."

@ericrhodes1 In terms of distortion you are correct although its nothing to do with the output devices. It has everything to do with the patents Bruno controls. 

But GaNFETs do have a nice advantage over MOSFETs in that they are so much faster, with a lower turn on resistance, so its impractical for the device to have leads. So they are very thin and usually 1/4th the size of a postage stamp or less.

With no leads (just solder pads) it is far easier to control parasitic inductance on the circuit board! This allows the design to be lower noise. This is important since any switching noise that leaks out of the amp (as Bruno has pointed out) can interfere with other components in the system (essentially acting as Radio Frequency Interference). So its paramount you can keep that noise down so other components can sound/perform their best! 

In our class D for example the main source of noise is actually the power rectifiers in the power supply- not the module (which is of our own design). The rectifier noise was easy to suppress; as a result our class D amps radiate (thru the ground, AC line and through the air) less noise than many tube amplifiers. 

A secondary issue but one to be concerned about is the fact that many class D amps based on Bruno's modules don't have adequate power supplies or input buffer circuits since the modules are sold without those. Both are vital to allow the amp to perform properly. 

So even though the Purifi modules are the lowest distortion class D modules, that isn't the same as 'all amps using Purifi modules are equal'. So as a result, GaNFET amps can go toe to toe with amps using those modules. 

What this means is you still have to listen to the particular class D choice you might have in mind. Not supposed to work that way IMO but here we are. 

@atmasphere true, but it's easy enough to find or build decent power supplies and input buffer circuits for them. And not every GanFET has a great power supply or input circuit. Just sayin. 

 My own experience has been, GANFET amps add "tonal warmth", like tubes, and, without the nasties of tube ownership. I find the GANFETS I have tried in my system, to "soften and round out transients", as I do with tubes. I have also owned designs using MOSFETS, BJTs, JFETS, IGBT. Plus, the number of chip amps I have owned. I do believe, based on my own listening throughout the years, "each" has its own distinct character, whatever the implementation. I will also tell you...in my system, all of these little class d amps using the separate power supply/transformer, sounded like jokes. zero balls. 

I met a DAC designer at a Denver headphone meetup last month. His name is John La Grou and his new DAC is the imersiv D-1. It is really a leap with respect to existing DAC technology. They have come up with a process they call multi-path. I own this DAC.

This same multi-path design can be used with DACs. amps, microphones, etc.. I think this company is targeting a $100M IPO to make this multi-path ecosystem happen,

John told me his next project is to make an amp with this technology using Bruno's Class D, likely Purifi. He said he was friends with Bruno. Not sure what that entails with the design.

I have a feeling this amp is going to be to Class D amps what the imersiv D-1 DAC is too digital. Maybe not just Class D amps.

Home - Imersiv

BTW - that comment on the IPO was from something I read on the internet.