new GAN amplifier

Thorsten Loesch
All Class D amplifiers are essentially delta-sigma DAC’s.

This statement is false.

So you believe the atmasphere statement, that his OTL’s can do a nice job of driving the Wilson Alexia’s as well?? also delusional🤦‍♂️

:)  He had the amps built to match the finish of the speakers- here's what they looked like:http://www.theaudiobeat.com/equipment/atma_sphere_ma2_mk31.htm

@georgehifi 

Loudspeaker efficiency 101:

Less efficient loudspeakers tend to have more voice coil heating and so are more compressed than loudspeakers of higher efficiency:

http://www.aes.org/e-lib/browse.cfm?elib=5251

https://www.stereophile.com/reference/1106hot/index.html
https://www.researchgate.net/publication/323935533_Voice_coil_temperature_in_loudspeaker_performance...
https://www.tonmeister.ca/wordpress/2014/01/16/bo-tech-thermal-compression-compensation/
http://www.cieri.net/Documenti/JBL/Documenti%20tecnici/JBL%20-%20Dynamic%20Linearity%20and%20Power%2...
https://www.linkedin.com/pulse/power-compression-vs-thermal-distortion-loudspeaker-alexander-wilson
-and on and on. This is simply not a matter of debate. As you can see from these and similar related documents, all loudspeakers have voice coil heating as their actual efficiency is rather low. You get less voice coil heating if the driver is more efficient. This results in less compression. Now you might think that you can just throw more power at a lower efficiency speaker to deal with this, but this results in more heating- exacerbating the compression effect.

because the speakers also have to be least colored most dynamic you can get, unfortunately that usually means they’re hard to drive.

This statement is false. Less efficient speakers also tend to be less dynamic due to voice coil heating. A secondary reason is the harder any amplifier is made to work to drive a speaker, the more distortion it makes- which is audible as reduced detail and increased harshness.

@atdavid is correct. By the time anyone had modified a MOSFET amp to run with BJTs it would be an entirely different amplifier. There simply would be no way to compare 'before' and 'after'. Its highly unlikely that anyone ever did a mod like this unless the amp was gutting for its chassis and power supply.