Hi Joe,

> If I understand correctly, the newer A130 VCAs will work with DC,

but

> my older one doesn't. Is there a simple mod to make it work with DC

You do understand correctly on the first statement - Dieter says so
in post #2770. The answer to the question is almost certainly 'no' -
I wouldn't like to say that it cannot be done at all, but if it can,
it's unlikely to be simple. The summing input on the CEM3381 chips
used are referenced to -2.1V, which means for ordinary use with audio
type signals, i.e. AC, you must have a decoupling capacitor in
to 'nullify' the effect of this DC offset. If you were to remove it,
then the gain on positive going signals would be more than negative
going ones, i.e. I think it would go haywire.

Tim