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Hi to all of you,
I have serious trouble with a Selmer Bassmaster. Go the a rather used condition. OT-Brackets brocken, weird cap-replacement and a bad hum/noise.
What I did:
- new electrolytic caps
- new bias diode and caps
Fired it up and it sounded fine. If there wasn't still that disturbing noise.
Pulled out all preamp tubes->still that noise.
Took off the b+ from the PI, grounded the coupling-c's and the noise was gone.
I suggested a weird thing with the bias circuit, so I replaced the bias supply with a battery (-37V)
Still that noise. Took the scope and looked at the supply voltages. they seemed fine.
The schematic is available at:
Selmer Bassmaster 50 Schematic
Any suggestions or hints?
thx in advance
Gerhard
I have serious trouble with a Selmer Bassmaster. Go the a rather used condition. OT-Brackets brocken, weird cap-replacement and a bad hum/noise.
What I did:
- new electrolytic caps
- new bias diode and caps
Fired it up and it sounded fine. If there wasn't still that disturbing noise.
Pulled out all preamp tubes->still that noise.
Took off the b+ from the PI, grounded the coupling-c's and the noise was gone.
I suggested a weird thing with the bias circuit, so I replaced the bias supply with a battery (-37V)
Still that noise. Took the scope and looked at the supply voltages. they seemed fine.
The schematic is available at:
Selmer Bassmaster 50 Schematic
Any suggestions or hints?
thx in advance
Gerhard