Tube Amp Archive

Thanks everyone for your info and feedback. I'm in no rush (this will likely be a fall/winter project), so I'll have a bit of time to research and learn. I do agree that this thing would likely be best suited to a pre-amp playground with the multitude of sockets and knobs, and best to leave the outp...

I put in a 3-prong power cord, hooked up a guitar (pin 6/7 of one of the input transformer sockets) and took it for a short spin. It's still very low/mid-low frequency heavy compared to a guitar amp. The 'speech filter' switch does a pretty good job of cutting down the lower frequencies to bring it ...

Well, thanks to Ingenium Canada (the Canadian Science and Technology Museum) I now have an actual schematic and manual!!! I've attached a .pdf of the manual as well as a .jpg of the extracted schematic. Hopefully someone can chime in on what's going on with the output transformer. And why so many B+...

Thanks Nuke - sounds like you're onto something. There are a LOT of wires going into the Ouput Transformer (12 total - 6 'taps'?). Most of those white wires are labeled w/ color codes (eg. RED YLW), but with all that tidy hand-tied wire bundling, it's hard to tell where everything is going. It's bee...

Here's a photo of the back - pretty standard speaker impedances.

Yes, there are 3 mic inputs (each with a step-up-transformer), and a Phono channel - 2 RCA jacks, one labeled MAG (for moving coil?) and on XTAL (piezo?). I tried the guitar through the phono jack - the amp is definitely not voiced for guitar (yet) - it's very low-mid heavy. It does start to sound p...

Those input transformers sell for ~$1k a pair in the audiophile world. Yup, they sure do. I hadn't looked those up till you mentioned it, then the light went on, "Northern Electric" and "Western Electric" and those are very good quality plug-in line transformers. Looks like the OP scored the trifec...

Hello all. I've been looking at rounding out my small collection (ie. two) of amps and stumbled upon an old PA mixer/amp (appears to have been from a church). It's a Northern Electric PA35A and looks like it would make a decent foundation for a really good guitar amp. It's set up with 5x12AX7s, 2x6C...