luke.leighton <luke.leighton <at> gmail.com> writes:
it is with much sadness and regret that for parts in the flying squirrel i say goodbye to the LM13700M, a part with a huge and rich history, having seen its first emergence into the world around 1967 even predating the moon landing. the reason is simple: the bias for the diodes is 3x 0.7 volts and on rails of +/-2.5V it's simply not enough. i'm seeing silence at low volumes... and then huge clipping. i simply don't have time to resolve this.
For those of us with electronics experience but maybe not name recognition of ICs: the LM13700M is a dual op-amp, which Luke may be trying to configure as a Class B amplifier (push-pull). Since his input voltage is so slight, the circuit is spending too much time in cutoff, except where it reaches saturation.
Luke, using a class B amp is going to result in crossover distortion. I think that's what you're seeing. So, you're replacing your homebrew power amp with a C-Media USB Audio device? Is this directly connected to the USB lines, or after a hub?
Derek