It is not just the heat output of your power supply that is the limiting
factor with regards to current draw. Every component that the load draws
current through must be considered.
The transformer in particular. I have found that many Polysix and
Mono/poly transformers operate quite warm and get warmer as they grow
old. I've no idea what the original transformer's maximum current output
is on these synths but if I was adding a bunch of stuff to my Polysix
I'd certainly consider replacing the transformer so it can cope with the
load I'd be drawing from it.
The transformer and the smoothing capacitors should also be rated for at
least twice the DC draw.
A quick rule of thumb is that if you can't touch any device for more
than ten seconds then it's too hot (and probably above 60C). That's in
the UK mind and we have a much lower ambient temperature normally.
I'd recommend measuring the current output of each DC supply line
without the additional circuitry, and then with all the additional
circuitry. If it's more than 25% difference you're almost certainly
stressing it out.
Tony
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