Tube Amp Archive

I'm in the process of building this amp. I finished the power supply wanted to check if I'm getting the right voltages out it. The A, B, C and D voltages are all around 447 volts. Should the voltages be around the same value if there is no load hooked up?

Thanks,
Zack

Is there a standard pinout for this kind of transformer?. It came from a Dynamic Instruments dc-amplifier. It is marked:
DIC1391A
PA 574
CX9
Pins 16 and 17 are marked sh1 and sh2.
18 is ground.
Is this an appropriate trans for a 5E3 circuit?
Thanks,
Zack

Re-soldered the power resistors.

Zack

That fixed it.
Thanks,
Zack

I have a fender Blues deville that stutters when the drive channel is engaged. The signal is fine until it hits R20. Anyone have any idea what it could be? Here's a video of an audio probe on both sides of R20. http://www.youtube.com/watch?v=A-0K4jIMvNU Schematic: http://www.blueguitar.org/new/schem...

I got a new rectifier tube and it seems to be working. There's a 11 volt drop across the 1k resistor so a .25 watt resistor should do the trick. I'm having a problem with the volume pot. I replaced the old 500k pot with a 500k alpha pot twice and both of them failed. Any idea what could be wrong? Do...

I turned it on today and there were purple bolts arcing in the rectifier tube, so I guess that's no good. I replaced that resistor with a 1 watt. Everything was working last night including the tremolo.

Thanks,
Zack

The filter caps are brand new. The resistor was still smoking when I upped the wattage. But it seems fine now. The plate voltages are a little high, 300 volts on the 6bq5s as opposed to 270v in the schematic. Would that cause that resistor to over heat?

Zack

I re-flowed the solder on the filter caps and it seemed to clear up the problem. I also replaced the resistor with a higher wattage replacement. Thanks a lot.

Zack

I have a gibson ga-8t that keeps burning up a 1k rectifier cathode resistor (circled in red). Anyone have any idea what could be causing this? It stats burning with the output tubes removed. Could it be a bad rectifier? [img:750:402]http://img512.imageshack.us/img512/6997/ga8vx2.jpg[/img] Thanks, Zack