Tube Amp Archive

I hooked up my Fluke 87 multimeter to read amperage (mA, A). Leads, Red to 6v wire from transformer. Black to pin 2, 7591 tube. other 6v transformer wire to pin 7, 7591 tube.

So I ran just the heater voltage, nothing else. The 7 tubes all glowed, transformer didn't get even warm. I got a current reading of 1 mA. Do I need to hook up the B+ as well for this test?

i ran the heaters on the 7 tubes. The voltage unloaded was 6.99v ac. With all tubes heated 6.55v ac, a drop of 6.3%. The total current draw for the tubes (per the manual) is 3.1A. (Kinda high?)
is there a good source for info on this amp? A good source for power transformer?
Thanks,
Tom

So, it turned out the power transformer was bad. I've got a used PT from I don't know where. It reads 670vac across the HT leads (schematic for Ampeg G15 says 720vac). it's set up for a 5volt rectifier which i won't use. It's a gray colored casing with CS 5779 number on it. also has the numbers 5001...

What about cathode stripping with the solid state rectifier?

Steven, The power transformer is good. The previous owner tried to do some tinkering and had the screen grids of the 7591 output tubes connected at pin 4 to the filter cap and at pin 8 to ground. It burned up the 470 ohm resistor. He also had the cathode pin 5 connected where the control grid should...

Thanks Steven, but I don't know how the switch is wired. What wires connect to it? and from where they originate. Maybe you could reference my diagram and describe the connections. i apologize for my limited understanding.

i hear you, sluckey, but I'm still not sure how the wiring goes. Can you download my wiring diagram and do a layout? Or should I just fill it in myself and post it for approval? I'm mainly confused as to where the purple wire connects and also the center tap (same place?). I was planning on attachin...

Thanks, reeltarded. But can you draw those solutions onto my diagram? I want to use the original switches.
Tom

Switches fuse.jpeg '66 Ampeg G15.jpeg Wiring layout Ampeg G15.jpeg I have the same situation as 65greg. a 66 Ampeg G15 that someone had really messed up the wiring. Having trouble wrapping my head around the solution, mainly as it pertains to the wiring of the hardware. Could someone please indicat...