06-11-2023, 10:14 PM
Hi All!
I picked up this amp chassis for $20 today. No tubes or documentation included. The only markings are a stamped circle with "32E" inside. The over-all circuit appears to be push-pull using some kind of octal power tubes like 6v6, 6l6, etc (pin 1's unused, pin 3's [plate] tied to one side of opt primary, pins 2 and 7 heater). Here's where the odd comes in. The screen grid pins (pin 4's) are tied to the cathodes (pin 8's), which are tied to what appears to be a filter capacitor positive voltage node. Both grids are tied together, and go to the 9-pin octal style socket. The power supply uses solid-state rectifiers, and appears normal enough. There appears to be both main B+ and a single-diode negative voltage source, and there is what looks like a bias POT with no guts which is NOT tied to the power tube grids. I can't figure out what exactly its purpose was. There doesn't appear to be any specific grounding scheme, as some grounds go to chassis, while others tie together in a semi-star style. My gut instinct is to just gut it and start a build from scratch. However, if this is a bit of a rare amp configuration worth a possible resurrection, I'd consider that undertaking.Any help/input appreciated!
I picked up this amp chassis for $20 today. No tubes or documentation included. The only markings are a stamped circle with "32E" inside. The over-all circuit appears to be push-pull using some kind of octal power tubes like 6v6, 6l6, etc (pin 1's unused, pin 3's [plate] tied to one side of opt primary, pins 2 and 7 heater). Here's where the odd comes in. The screen grid pins (pin 4's) are tied to the cathodes (pin 8's), which are tied to what appears to be a filter capacitor positive voltage node. Both grids are tied together, and go to the 9-pin octal style socket. The power supply uses solid-state rectifiers, and appears normal enough. There appears to be both main B+ and a single-diode negative voltage source, and there is what looks like a bias POT with no guts which is NOT tied to the power tube grids. I can't figure out what exactly its purpose was. There doesn't appear to be any specific grounding scheme, as some grounds go to chassis, while others tie together in a semi-star style. My gut instinct is to just gut it and start a build from scratch. However, if this is a bit of a rare amp configuration worth a possible resurrection, I'd consider that undertaking.Any help/input appreciated!