putting a Gates solid statesmen preamp into a 51x module

hey chaps, I have a small gates preamp from a 70s solid statesmen broadcast console that I would like to put into a 51x module.  It physically fits fine with room to spare and runs on 30v (see schematic).  So I'm looking for a little advice.  I can add the jlm go-between board for pad and phantom easily enough and a jlm Regurgitator or similar opamp based balanced out (the jlm is my preference because it also allows a trim of +/- 18db) but I'm wondering how to power it.  the schematic has it running at +30vdc and I'm wondering whether I should use the +24vdc rail of the 51x or use the -16v rail as ground and the +16v rail as positive to give a 32vdc which should be within spec.  The regurgitator will run off +/-16v no problem.  I'll recap of course and could use a resistor to drop the voltage to 30v but is it worth it for the extra 6v over the +24v rail?  Any other problems you can see with racking it?  I was also thinking of putting a switch in to alter the input impedance because the transformer has that possibility and possibly adding a transformer on the output... Thanks!

If you haven't seen it, I believe PRR did a walkthrough on this circuit once, probably informative regarding a few changes. 

> I believe PRR did a walkthrough

Doesn't look familiar?

It is a single-ended circuit. Run it on one power rail or you will get messed-up.

It isn't so fussy, it should run on +24V with minor trim. Suggest tacking another 10K across R6 to keep front-end bias similar. The output node (R16) should bias to half-supply or a volt higher. Since you propose yet another stage behind it, a few volts either way don't matter.

I don't see a point in having a 37 Ohm input.

PRR said:

I don't see a point in having a 37 Ohm input.

Click to expand...

Only if you have some early 30 ohm mics, or want to tap an RCA whatever 44/77 down to the lower output Z. 

The walkthrough was a million years ago, it's here somewhere.