I don't have an Audio Buddy, but I do have a Duo.
Rob Danielson wrote:
> ... I recall
> discussion about Len Moskowitz's involved M-Audio
> Duo modification for portable DC which also has
> the 10 VAC input.
Len's portable power for the Duo is a high-quality
inverter -- gotta be "true sine" output for the
Duo quality to be any good. I'm pretty sure that
the clean AC is needed by the PS's full-wave bridge
to generate the +/- DC rails. I don't know if the
phantom supply also needs clean AC as well. I have
opened up my Duo, and the voltage multiplier for the
phantom kinda stands right out ... a string of 8
(relatively) big electrolytic caps and 7 diodes.
I haven't bothered to put a scope on the ladder
to see if it's driven at AC line frequency, or
if the 555 timer nearby feeds it some high freq
square wave. It's only easy follow a percentage
of the traces on the board.
-- Mike
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