About 20 years ago, I bought this Sessionette:75 for a fair price, considered the wear. I can't recall exactly when the sound problem occured first, but there was some loud crackling/distortion with heavy chords. I temporal "solved" the problem by an extra resistor between the pre- and power-amp.
After not used the amp for many years, the crackling/distortion was back. So I removed the temporal resistor and it sounded fine again (don't ask why).
After a few days the sound was completely gone except for heavy chords which produced static/crackling/distortion. Then suddenly the pre-amp died except for the reverb.
Because I really like this amp, I decided to really solve the problem, knowing this is a pain because of the short cabling (see attachment).
I replaced all op-amps, checked the Voltages, sprayed the pots, followed the signal and concluded there should be no problem.
The headphones worked fine, but the speaker remain dead.
My multimeter told me the resistance of the speaker was 11 M-Ohm and not the 6.4 Ohm that it should be.
And now my question: Can a speaker die this slowly and give the sound issues described above?
I'm hesitating to swap with a G10-50 for testing, while I'm not sure what the cause was for the problems and the dead of my G12-80.
BTW. The 680R/3W resistors (R32, R33) are extremely hot, could the 2N3053 dissipate that much power for it is maybe defect?
Thanks.
After not used the amp for many years, the crackling/distortion was back. So I removed the temporal resistor and it sounded fine again (don't ask why).
After a few days the sound was completely gone except for heavy chords which produced static/crackling/distortion. Then suddenly the pre-amp died except for the reverb.
Because I really like this amp, I decided to really solve the problem, knowing this is a pain because of the short cabling (see attachment).
I replaced all op-amps, checked the Voltages, sprayed the pots, followed the signal and concluded there should be no problem.
The headphones worked fine, but the speaker remain dead.
My multimeter told me the resistance of the speaker was 11 M-Ohm and not the 6.4 Ohm that it should be.
And now my question: Can a speaker die this slowly and give the sound issues described above?
I'm hesitating to swap with a G10-50 for testing, while I'm not sure what the cause was for the problems and the dead of my G12-80.
BTW. The 680R/3W resistors (R32, R33) are extremely hot, could the 2N3053 dissipate that much power for it is maybe defect?
Thanks.
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