Sounds like it could be one of the coupling caps, John. Coupling caps are capacitors used to remove the DC component of the signal from the output of either the DAC or the op-amps functioning in the low-pass filter stage or, in some cases, the I-V (current to voltage) stage. On a single supply (that is, only positive voltage rather than + and - voltage), the way you get bipolar swing is to apply an offset, swing against that, then use coupling caps to remove the DC so you get a +/- AC swing. When the caps go bad or otherwise wear out, you can get distortion.
post #361 of 450
2/16/07 at 5:01am