distortion...mosfet

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Nico Ras said:
Hi Richard,

I am surprised at some of the comments you received. Firstly if your LPT is well matched, degeneration resistors increases distortion.

There is nothing uncommon about driving lateral mosfets from the VAS, it works fine.

The amplifier performs well at high frequency and at 100kHz range at full power, THD is a not too shabby 0.12% and at 1 kHz it is around 0.006% better than most.

TIM is not lurking around the corner waiting to mug you. The phase response is ruler flat throughout the audio band with only -8 degrees at 100 kHz there are many high class designs that is three to four times this high.

The slew rate is > 28V/us and better than most. There is no notable over or undershoot using square wave.

In my opinion there is absolutely nothing wrong with your simple amp and if you like what you hear then that is what it is all about enjoying your music.

Kind regards

Nico

Nico,

Degenerating the LTP and re-adjusting the feedback compensation accordingly (to keep gain crossover frequency the same) virtually always REDUCES high-frequency distortion.

0.12% THD-20 is VERY shabby.

Cheers,
Bob
 
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