In Reply to: RE: Feedback - Part 4 posted by Story on February 15, 2024 at 06:09:53:
The type of amplifying device - BJT, J-FET, MOSFFET or GaNFET - doesn't really make a difference to the discussion. They all thave non-linear Voltage-In to Current-Out characteristics hence they distort and, hence, feedback is needed to correct that.
The GaN advantage is their bandwidth - maybe doesn't bring too much to the linear amplifier table but it is advantageous for switching amplifiers in that they can switch more quickly and push the switching noise further from the audio band. They are the device du jour for switching amplifiers. Going back to Bruno Putzey, when asked about re-designing his Purifi module to use GaN instead of MOSFETs he said that there would only be a marginal improvement because he has applied a lot of feedback so errors are well suppressed. He thinks that maths is more important (i.e. being able to design an architecture with a lot of feedback across the audio band) than sexy FETs. If designers can't do the maths, and have lower feedback designs, then they will see more benefit from GaN.
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Follow Ups
- RE: Feedback - Part 4 - 13th Duke of Wymbourne 11:56:24 02/15/24 (4)
- RE: Feedback - Part 4 - morricab 07:24:38 02/16/24 (3)
- Sort of-ish - 13th Duke of Wymbourne 14:52:23 02/16/24 (2)
- RE: Sort of-ish - morricab 13:14:23 02/18/24 (1)
- RE: Sort of-ish - 13th Duke of Wymbourne 00:01:37 02/19/24 (0)