Tube Amp Archive

Hi guys. I'm looking for some technical advice. I gutted an old Japanese ELK amp, and want to rebuild it using a Fender AA964 circuit. The problem that I'm having is that the original ELK PT only has a 6.3v filament winding for the rectifier tube, (rated at 1A) so I can't use the specified GZ34 rect...

This circuit is similar to a bridged attenuator (as referenced in the diagram) but in that case the pot wiper is grounded and the "bottom" pin goes to the C3-C1 node. You can find references to that circuit on the web. To calculate the center frequency I'd select the cap value first, say 0.1uF (100...

Hi all. I'm new to this forum and this is my first post. I recently undertook to install a notch filter in my 18watt EF86 amp. I found a schematic online somewhere for a variable 400hz notch filter, which works great. I wired it with a pot going to ground, so the intensity of the scoop could be vari...