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Needed schematic for Gregory bass 60A.
I don't know who made these, Google says Harmony made but who made Harmony amps? My initial thought was Danelectro as the metal chassis slides in notches in the side wood pieces. After working on it, the chassis is much thicker than Silvertone Danelectros i have seen before.
Major mouse nest, major rust, output transformer is fried. Some wires chewed, gonna need new jacks, maybe new pots, maybe new sockets. Waiting on the owner to get back to me as to how much money he wants to sink into this.
Was worked on before, or should i use the term "butchered" before. Old diodes were simply left hanging by 1 end. Terrible soldering and extra long wires everywhere. Power transformer has 2 taped wires on secondary, do not know if original, may be 5vac, didn't test yet. Guy wants to use it as a guitar amp. Currently wired as grid leak bias 12ax7's. All disc capacitors, seem to be good. Weird long tail pair ( i think) with (2) 68k and (2) 10 meg resistors.
Output section, factory 150 ohms cathode resistor, paralleled with a later added 234 ohm resistor. Outputs are weak 7189a, do not know if original tubes. Replaced output trans with a weber 8k/8ohm just to get it running.
I have the output section working, 425 plate voltage and 375 screen , running on 6p14p-k russian tubes (14v) 250 ohm cathode resistor w/47uf. I am calculating 90% diss. Will these russian 6p14p-k tubes hold up to 400v? I have no -ev just plain and -k. It was a bass amp so maybe they were really pushing the output tubes, original output transformer was fairly big.
Filaments are at 7.2 vac so i have to drop that a bit. maybe i can buck the primary with the extra secondary wiring to drop all the voltages.
I don't know who made these, Google says Harmony made but who made Harmony amps? My initial thought was Danelectro as the metal chassis slides in notches in the side wood pieces. After working on it, the chassis is much thicker than Silvertone Danelectros i have seen before.
Major mouse nest, major rust, output transformer is fried. Some wires chewed, gonna need new jacks, maybe new pots, maybe new sockets. Waiting on the owner to get back to me as to how much money he wants to sink into this.
Was worked on before, or should i use the term "butchered" before. Old diodes were simply left hanging by 1 end. Terrible soldering and extra long wires everywhere. Power transformer has 2 taped wires on secondary, do not know if original, may be 5vac, didn't test yet. Guy wants to use it as a guitar amp. Currently wired as grid leak bias 12ax7's. All disc capacitors, seem to be good. Weird long tail pair ( i think) with (2) 68k and (2) 10 meg resistors.
Output section, factory 150 ohms cathode resistor, paralleled with a later added 234 ohm resistor. Outputs are weak 7189a, do not know if original tubes. Replaced output trans with a weber 8k/8ohm just to get it running.
I have the output section working, 425 plate voltage and 375 screen , running on 6p14p-k russian tubes (14v) 250 ohm cathode resistor w/47uf. I am calculating 90% diss. Will these russian 6p14p-k tubes hold up to 400v? I have no -ev just plain and -k. It was a bass amp so maybe they were really pushing the output tubes, original output transformer was fairly big.
Filaments are at 7.2 vac so i have to drop that a bit. maybe i can buck the primary with the extra secondary wiring to drop all the voltages.
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