this thing is done, we put a 1000 ohm resistor across the compressor defeat switch, what this does is that when the sw is in the defeat mode, (open) it has 1000 ohms across it which allows some of the sensing signal to still get thru,
so the amp is putting out some serious power now, this amp tends to suppress spike in volume, if you feed a steady sine wave into it then you get max power all the time, but a quick note on the bass will trigger the clamping action,
also fixed a scratchy pot, replaced both caps on either side, still scratchy, turns out we had a nuked 1N4148 neg rail diode that was punched thru, this was reverse biasing the caps and probably screwing up the wave form as well,
found this on the web:
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Your friend has just discovered why Peavey's DDT sucks!
I had a Mark III or IV back in the mid-1980's, also had a Peavey M3000 power amp with DDT (which, at least on that unit, was defeatable with a push-pull gain pot). To my recollection the DDT on the Mark III or IV was not defeatable...and, as your friend discovered, there was no way to get any headroom out of those Peavey amps because of this. Stupid design.
(Edit: iow, it's a fundamental flaw in the design of the DDT circuit, or of Peavey power amps in general. Defeat the DDT and the amp clips, leave the DDT engaged and the compressor restricts output. Either way there's no way to get adequate dynamic headroom out of these amps.) "
DDT defeat sw and connector with white jumper cut, this jumper replaces the sw so that the DDT was always on,
