A good class-D amplifier has very low distortion because the oscillator operates at about 500kHz so that the sum and different frequencies can be completely removed by a simple lowpass filter.
I mean, if there is music with a piccolo and guitar, those frequencies will mix in the audio range and cannot be filtered out. That is the type of test that I did.
I mean, if there is music with a piccolo and guitar, those frequencies will mix in the audio range and cannot be filtered out. That is the type of test that I did.
That is called "intermodulation distortion". You can hear about 0.1% on some kinds of tones and music. A good linear or class-D amplifier has 0.03% distortion or less.
Poor amplifiers have 10% distortion or more.
I mean, if there is music with a piccolo and guitar, those frequencies will mix in the audio range and cannot be filtered out. That is the type of test that I did.
That happens in ANY amplifier, not just class-D - it also happens to your ears, if you are in a room with both piccolo and guitar playing they mix together.
It's a VERY difficult thing to measure, it sounds like your old 'amplifier' was really, really bad!.