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I picked up this Eastern Amplifier, which I believe has a lot of potential. I recapped her and put a grounded 3 prong cord, and she sounds good; however, the preamp tonestack circuit is really noisy and strange to me. Appreciate any ideas for a rewire. Removing the 6LS7, eliminates the noise by the way, and it's a good NOS National Tube. Attaching a schematic I was able to pickup off internet. Thanks for your ideas!
On the front of the chassis the amp says:
Eastern Amplifier
Licensed under U.S. Patents of American Telephone and Telegraph Company and Western Electric Company incorporated (see label inside).
Model G1A
Serial NO: 6597
I noted an error or two on the schematic, the tone pot is wired to pin 5 of the 6V6 versus pin 3. I attempted to rewire like the schematic and the noise was at least 5 times worse, so I'm pretty sure this was just a schematic error. Also, the amp had a 1KoHm resistor to gound, I changed it to a 270oHm and that reduced the noise as well. I still plan to replace some resistors that had drifted upwards a bit but not too badly. The preamp section on this baby's got to go, appreciate advice.
SIG
On the front of the chassis the amp says:
Eastern Amplifier
Licensed under U.S. Patents of American Telephone and Telegraph Company and Western Electric Company incorporated (see label inside).
Model G1A
Serial NO: 6597
I noted an error or two on the schematic, the tone pot is wired to pin 5 of the 6V6 versus pin 3. I attempted to rewire like the schematic and the noise was at least 5 times worse, so I'm pretty sure this was just a schematic error. Also, the amp had a 1KoHm resistor to gound, I changed it to a 270oHm and that reduced the noise as well. I still plan to replace some resistors that had drifted upwards a bit but not too badly. The preamp section on this baby's got to go, appreciate advice.
SIG
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