Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Misc Schematics and Layouts => Topic started by: tomasinator on January 05, 2023, 09:11:47 pm
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Anyone recognize this amp?
(https://i.imgur.com/9QCgvLf.jpg)
(https://i.imgur.com/7EGMeHr.jpg)
(https://i.imgur.com/0RkXFLz.jpg)
(https://i.imgur.com/XYWz5lo.jpg)
The closest schematic I could find is the Supro model S6651, but that's not it, because my amp has a 6973 tube, which the S6651 schematic doesn't have.
The power supply and dual 6L6's are on a separate chassis on the floor of the amp. The case looks like this. About 30 years ago I was riding home from a mountain bike ride in Saratoga, CA. It was trash day and someone had thrown out this amp. They had taken it apart and the pieces were partially in the garbage can. I rode home, came back with my car, and grabbed all the pieces. I reassembled the case, got tubes, and the amp worked. Last year, however, the basement flooded and the amp sat in a foot of water. I let it dry out for 10 months and miraculously, the power transformer did not get shorted out. I want to fix it but need a schematic.
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It's certainly a Valco, they made "Star" amps under their own name. Try Terry Dobbs at https://valcoamp.com (https://valcoamp.com).
You might post some hi-res pics of the circuit board and wiring.
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Plenty of pics on the net. Here's some...
https://reverb.com/item/56352722-1965-supro-big-star-2-x-12-tube-guitar-combo-amp-looks-excellent-sounds-great
It's very possible that the only difference between the S6451 and the S6651 is the output tubes. Everything else may just be the same. Does your amp have a dual ganged volume control in the Trem/Reverb channel?
Terry Dobbs probably has a schematic...
https://valcoamp.com/?fbclid=IwAR0s6MJ1GvwpeeqLRt4P6RCZ256phk1W95Z6tdG5eSvheSdhGYCjHz2AuHY
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It's certainly a Valco, they made "Star" amps under their own name. Try Terry Dobbs at https://valcoamp.com (https://valcoamp.com).
You might post some hi-res pics of the circuit board and wiring.
Here are some hi-res picts. There's no circuit board(s) -- it's all point-to-point wiring on terminal strips. Here's the power supply and power amp:
(https://i.imgur.com/WiNI9Cb.jpg)
Here's the guitar input side of the pre-amp. Rust is a big issue.
(https://i.imgur.com/Y7eC0K0.jpg)
Moving to the left:
(https://i.imgur.com/zIfWiEl.jpg)
Left side:
(https://i.imgur.com/Yf5DZ7x.jpg)
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Plenty of pics on the net. Here's some...
https://reverb.com/item/56352722-1965-supro-big-star-2-x-12-tube-guitar-combo-amp-looks-excellent-sounds-great
That's exactly the amp. It's good to know it's a S6451. I couldn't read the rust-encrusted letters on mine. I thought it read 5645T.