[no subject]

Another thing I've noticed is that the Mockingboard V1 has some
additional 0.1uF capacitors on the +5V line going into the AY-3-8910
and 6522 chips. Could the absence of these capacitors be responsible
for the noise I'm hearing?

I've gone over the additional amplifier circuitry that I added, and
everything appears to be wired correctly. Remember, the rest of the
circuit was working fine (albeit without amplification).

Is anything else I should check to eliminate the bus noise?

Any help would be greatly appreciated!

Cheers,
Mike