Good articles here. Components don’t need to be active to add noise and distortion.
Resistors cause Johnson noise:
https://www.analog.com/en/analog-dialogue/raqs/raq-issue-25.html
Metal core inductors cause hysteresis distortion:
LSA Voyager GAN Amplifier
Just got mine last week. After 24 hours of play all I can say is that this is not your father's class D amplifier. There is not one thing about its sound that reminds me of the class D gremlins that I do not like. The low end filled in and now has deep impact, the midrange is the love child of a beautiful tube and clean hybrid amp - just gorgeous. Highs are very clean and extended. Spatial cues are top notch. My system has had some damn good tube and solid state amps in it before and it has never sounded this good. I am blown away with the quality of sound coming from class D amplification at this price point.
This 300 wpc amplifier is a real winner.....
This 300 wpc amplifier is a real winner.....
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- 1033 posts total
If you test an amplifier using these dummy loads: https://www.parts-express.com/4-Ohm-100W-Non-Inductive-Dummy-Load-Resistor-019-015 The Johnson noise, as well as nasty distortion drowns out everything at -92dB THD+N. You need a bank of premium metal foil resistors. I use a bank of these: https://www.mundorf.com/audio/en/shop/Resistors/MResist_ultra/ And can measure up to -116dB THD+N with them. But most passive crossover use garbage like these:
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The "noise" from these resistors wouldn't even begin to register let alone reduce your THD+N to -92db at any reasonable amp power. You didn't state what power level you were using, so claims of distortion impact are suspect. No need for exotic and very expensive Mundorf resistors though. There are two parameters, one is thermal modulation, and that is a factor mainly of size, and the other one is voltage dependent resistance, and that just requires the right resistor material, it does not need to be at all exotic. Of course the speaker driver THD is -50 to -60db. |
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