by EWBrown » Mon Nov 22, 2004 7:01 am
I built up my Rev D board with the TF-100-48-UL mods, fitted it all onto a 10X9X1.5 inch "DD" chassis (same size as used for my K-502 amps in the photo gallery). Used a Hammond 270HX power tranny, a C-354 choke and the two TF-110-48-UL OPTs, and a set of JJ tubes. Oh, yeah, I added a 250 K stereo volume pot salvaged from an SCA-35 carcass.
How'd I manage to fit it all on on such a small chassis? Just like the K-502s, I built the board up with everything on the top surface, and then mounted it on TOP of the chassis. There was enough room for the OPTs and power tranny on top, and I put the C-354 inside the chassis (it just fit). I was going to use an original PA774 salvaged from an old ST-35 carcass, but it was one of the old "tar dipped" ones and lit ooked just a bit too funky for a new build...
Nice thing about having everything on top, it makes voltage measuring and bias adjusting so much easier and simpler, than having to go under the chassis.
Set everything up for 35 mA bias - it has a B+ of 355 to 360 VDC with the 270HX, and everything sounds great!
Photos will be forthcoming...
/ed B in NH
Real Radios Glow in the Dark