Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Solid State => Topic started by: smackoj on June 08, 2024, 05:50:23 pm
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Hello friends; I picked up an Ecoustic 112 for pennies. I have it running quiet and powerful again. However it starts to sound like 60 cycle hum when I turn up the reverb dial. It has a large spring tank. I have tried everything I know to try to get rid of the hum. I have tried 2 other tanks but no change. Can anyone look at this schemo and tell me if there is one or more places you see in the circuit that could be the problem? Please add this schemo to the Schematics Page. Thanks amigos
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I have tried 2 other tanks but no change.
did you change cables?
one of the grounds on the recovery side is a chassis ground, did you check for solid connection?
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I tried to isolate cable connections however the cables are routed up inside the chassis through a small hole and connected under the PCB with some type of push connectors. They look like the 'modern' elec connectors they sell at Autozune. The kind that are supposed to cut the insulation and pinch onto the copper wire. Weird. Trying to isolate them without having to take the PCB out to get to them. I may have to enlarge the hole in the bottom of the chassis so I can get close enough to unhook them?
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I tried re-attaching the wires to the funky weird connector but still hums. I will try to solder directly to the PCB. Hopefully that will clear the noise? Thanks for you help
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Update: Still humming but getting better. I am going to try replacing the RCA jacks. Thanks amigos