electrosound eq pics and PS ?s

Hi all, I just picked up a pair of electro sound eqs(well one electrosound and one peterson, but they are the same animal)

http://f2.pg.photos.yahoo.com/[email protected]

I've found electrosound and peterson tape machines, but no schematics.
the hookup looks perfectly straightforward, ins and outs were easy to trace, but I'm not sure about the power supply.
most of the discrete transistor stuff I have racked up, (some electrodyne modules, langevin am16s and some hamptone JFPs I built )are all happy on +24v

Since I don't have a benchtop vairable psu I'd love some help.

as far as the connectors go,
after the ins and outs are filled, there is a chassis ground, but the minus side of some el caps are also on these traces.
that leaves 2 tabs left, so I guess this could be signal ground and +, or it could be a bipolar supply... there are also some test points indicated on the circuit board, one at 1v, one at +10v and one at -10v.

hmm

Thanks for any help
sleeper

those look like tape machine EQ's. Are you trying to convert them to mic pre's?

dave

They are definately tape eqs. most of the electrosound stuff I've found are scientific and repro. tape machines and duplicators.

I was thinking of using them as line amp/drivers. I have an electronic drum kit on the far side of my studio and at 20bucks each I thought these might be nice on the back end of that, just to get a little iron, character, and a bit of boost into the line outs before they head into 40 feet of cable.

if you have ideas for mic pres I'd be interested to hear, but I doubt the eq will be anywhere near as sweet as the inductor based electrodynes I have.
those things kick much ass.

sleeper

I don't know thing one about tape decks though, never opened one up. do they typically run off of bipolar supplies or plain old +dc.

boink