Power supply for a preamp

[adam]

I have a preamp from an old Peavey Max bass system. This amp was basically a CS-800 with a bass preamp together in a rack from the factory (from what I understand).
The power amp is dead on this rig and I would like to be able to use the preamp with a more modern power amp. The problem I have, is that I do not know what this preamp requires in terms of voltage, etc.

My plan was to measure what was being fed to the pre amp from the original power supply, but the fault in the power amp was preventing me from being able to power things up to take a measurement.

Any ideas?

[52 Bill]

Contact Peavey with the name and model and ask for a schematic.

Once you have the schematic, you will either be able to repair or disconnect the power amp and still use the power supply to run the preamp, or you will know what voltages are needed by the preamp.

[olddawg]

I shudder to tell you this, but you can probably run the amp (at least for test purposes) if you remove the output transistors. Barring that you could disconnect the +/- rails to the main amp. Then you could measure your preamp supply lines and take a pre-out signal from the back panel jack into another power amp to see how it sounds. Frankly, I would just fix the power amp as is. A power amp.... well, just amplifies. I doubt if a more "modern" design would sound much different. Most of the coloration and noise floor will come from the preamp. And..... CS-800s are well known, well documented, bullet proof work horses. It is probably a simple, timely, and inexpensive fix compared to trying to re-engineer some monstrosity IMHO.

[Enzo]

Amen. That CS800 part should run forever. Easy to fix.

The CS800 module ought to disconnect by a 4-wire Molex connector if you just want to disable it.

get teh schematic from PV customer service, and you can then check out the power supply needs.