The problem is 0.06% THD is already too small to "hear" so you won't hear any difference between that and 0.00014%. Some fine tube amps are closer to 1% THD. There's WAY too much focus on THD, especially expressed as a %. Now, if those numbers referred to 3rd order harmonic distortion, not total, and 3rd order distortion is all there was, there MIGHT be a chance to hear the difference. But even that seems unlikely to me. Of course, I haven't heard such a thing so I'm only surmising.
The problem is really that single number THD is not much more useful than useless.
You have to step back one step and look at the spectrum. The details that get lost when this is collapased also loses all the important stuff.
dave
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My third build using Apex Microtechnology power op-amps. This one with the high power PA04 MOSFET chip since the amp was built to drive four subs. The design has 4 channels in a dual, 2 channel configuration, with two power supplies. One side puts out 2 x 140W into 4R when both channels are driven just below clipping. The PA04 chip is capable of 400W according to the data sheet, but I certainly don’t need 4 x 400W at home, and I wanted to get it all in a 19” 2RU case anyway.
The case is made mostly from recovered e-waste with the aluminum panels from an old Apple G5 Mac and the heat sinks from industrial servo drives. The extruded brackets, handles and feet were all that was purchased for the case.
Been listening for a while now and very pleased with the results. Thanks for looking.
The case is made mostly from recovered e-waste with the aluminum panels from an old Apple G5 Mac and the heat sinks from industrial servo drives. The extruded brackets, handles and feet were all that was purchased for the case.
Been listening for a while now and very pleased with the results. Thanks for looking.
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Well I can detect in an AB test a 7th harmonic of 100Hz at -65dB down, which is 0.056%, and my hearing's not that great. The commonly accepted limit is 0.01% as being undetectable for human ears (for THD - IMD is more complex). Detectability may not be quite the same as hearing a difference listening to random source material.
One issue with IMD is that ultrasonic tones can inter-modulate to produce audible tones across the most sensitive range of human hearing - electronically synthesised music can be a source of this - I've often thought about this but haven't heard of any thorough investigation of the issue.