by EWBrown » Mon Dec 06, 2010 3:34 pm
The A470s can be used, and most likely with better results than with the Hammonds.
If the mounting hole dimensions are the same, it will be a simple "drop-in" swap-out. Otherwise you may have to do some more chassis drilling
IIRC, the Hammonds may have a "reverse" primary to secondary phase relationship, if the amp sounds like a fog horn after the tranny change-out (Positive feedback, instead of negative FB), it is easy enough to swap the connections - the easiest way to do this, involving only two connections, is to swap the wiring from the two driver board outputs to the power tubes' control grids.
BTW, I just unboxed a 2003 vintage rev C ST-35, and will be giving it the EFB modifications, I just have to get myself an LM373, if I can't excavate one from the cellar goodies...
/ed B
Real Radios Glow in the Dark