red tape over the glass-cloth anchor to smooth the next layer out as it goes over the top,
looks like 1100T + 1100T = 2200 to 82 turns, so 26.829:1 turns ratio,
let's figure out what kind of a load they are putting on these 7591's with there RCA Tube Manual listed spec of 6600 P-P:
26.829^2 = 719.8:1 Z ratio, call it 720 and we can get load, 720 x 8 Ohms speaker = 5760 Ohms P-P
ani't gonna argue with engineers at Ampeg, but we could experiment with a 6600 ohm coil,
what would the turns be? 6600/8= 825 Z ratio, turns will be the root which is 28.72 x 82 = 2355
2355/2= 1177 turns, so if we add 77 turns to each pri section, we are at 6600 Ohms.
maybe for a home brew amp but since this is a shop amp, we gotta stay true to the orig.
we need a rough estimate of the AC voltage developed across the pri of the xfmr to determine how hard Ampeg is hitting this core. The owner of the company did not like rock and roll or distortion because it did not swing like jazz, but this is the amp that slipped between the cracks as it had some growl. (apparently he did not listen to Jimmy Reed!)
lets say 20 watts from a pair of 7591's ( we are running 140 ohm cathode resistor)
7591's can handle 19 watts a piece, right in between a 6V6 and an EL34,
so we figure speaker voltage and multiply by the turns to get voltage on the pri side:
V=root (RP) so V = root (8 Ohms x 20 Watts) V = root 160 = 12.6 pri side, x 26.83= 339 volts RMS
holy cow that works out to about 38 kilo Gauss, our limit is 18 KG with silicon, no wonder this thing barks like a dog, with rabies, yeah, no, this thing needs about 4000 turns, not 2200, wtf? jus sayin...
with this low turns count, this transformer, if it were cold rolled steel, could safely process about 6 watts without saturation, and that is hitting it pretty hard, especially since it is laced 1 x1 , sheesh, i gotta hear this thing,