possable DIY find

The Sam Ash in edison NY has a stagework stereo eq on sale for $59.99 IIRC, 1 rack space. I was thinking I could pull the faceplate and change it after I removed the circuit except for the internal PS. It has XLRs on the back. It might work for a dual green etc build. Does anyone own one that could check the PS voltages. Might be able to add SSLtech's 48V circuit to it.

Not knowing the PS voltages kept me from buying it.

Gus,

I don't know that particular unit (is it quite old??), but here's a few presumptions:

If it's a graphic equaliser in a 1U chassis, the chances are that it's an EQ based on op-amps. The older tube and transistor units relied on inductors- op-amps allowed the gyrator circuit to be realised- doing away with the inductors. A 1U chassis wouldn't allow much room for inductors in a multichannel EQ.

The easiest way to run op-amps is using a split +/- supply. So I'm guessing that no matter what, it'll be a +/- supply. The voltage- well, that will probably be +/- 15V. Could be 12, or 18, or even 24. But this can probably be easily changed- second presumption- 78/79xx voltage regulators. These can be easily swapped out and replaced with different values (obviously depending on transformer secondary voltage- but if you've got a +/-18V regulator circuit, you can pop some 15V regualtors in with only slightly greater heat dissipation...)

Also, I reckon the PSU will allow access to the secondary of the power transformer- so you will be able to do the voltage-multiplier phantom trick.

Just my hunches! (don't blame me if it's a +ve ground, -1kV @1mA max PSU )

:wink:

Mark