"racking" RCA BA-31c

Hi guys!  I've been out of the pro-audio world for a bit (got into guitar amps) but some friends asked me to rack-up some BA-31c's.

I've looked over a few of the threads and it seems pretty straight forward but I do have a few questions...

-The +6 gain strap isn't totally clear to me, I understand the schematic but I don't get where those points are on the actual unit.
-I think the input would be: + to pin C and - to pin E.  The output: + to pin F, - to pin D.  Does that look right?
-Given the fixed gain I'm thinking a hairball t-pad on the output and something on the front, like -5, -10, -15, -20 would be useful.  The output T seems easy but can some one point me towards a variable input pad.

for reference:
http://farm3.static.flickr.com/2597/4149558968_b4dedc3b0d_o.jpg

Thanks!

Output pad is a waste, I virtually never use it, and it doesn't sound great overdriven.  Maybe a 6 dB switched output pad, at least much cheaper to implement.  20 dB on the front.  Find PRR's analysis with proposed alternate variable gain control.  Worth hearing at least.  If that works well I'd do it over an output pad.  6 dB strap is pretty obvious on circuit board.  May say 40 or 46 between terminals, can't remember. 

Thanks Emrr, glad I didn't spend $120 on T-pads.

From PRR

Change R7 to 2K. Change R4 to 100R. Strap a 0-2K rheostat (2.5K reverse-audio pot) across terminals 46. This gives almost 20dB range of gain, both up and down from the stock gain. Keep pot-leads short. twisted, not shielded.

Click to expand...

Seems pretty straight forward, I can't seem to find a 2.5k reverse audio pot though.  I suppose changing the law of some other reverse audio pot would work, or maybe just a regular audio taper, or there's probably a way to calculate the right curve with a stepped rotary switch.

R7 and R4, are on two separate, vertically mounted circuit boards whose trace sides face each other.  I'll unscrew them later tonight, I'm guessing the 46 terminals are on the underside, or at least easily traceable from there.

The entire audio circuit is on one board, there are separate PSU boards underneath.  Don't confuse the two. 

Can't remember if this is the B or the C board, but there's not a lot of difference.  You can see r4, r7, and wires from the 46 strap all together near the input transformer.  Similar on all boards. 

Awesome, that's totally clear now.  I'm not sure what I wasn't seeing before.  I'll post back results regarding PRR's "gain strap mod".

Oh, Doug, what are those bypass caps you added?

0.1 film.