Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jazjamr on May 09, 2023, 07:58:30 am
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At idle with all pots at 0, my '63 Bandmaster has a shhhh shhhh shhhh noise. Obviously it's related to the harmonic trem. Any ideas?
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Not necessarily the trem causing this. If you have a lot of idle noise of some kind, the trem might also just indicate of attenuate that when wiggling. Does it always do that? Or what’s the deal without trem engaged?
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At idle with all pots at 0, my '63 Bandmaster has a shhhh shhhh shhhh noise. Obviously it's related to the harmonic trem. Any ideas?
I would start by changing V5. Use a low noise tube such as 7025 or 5751.
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Checked tubes yesterday. V5 was OK, V6 phase inverter was very noisy. Replaced JJ Ecc803 with ANOS Sylvania. Replaced RCA 12AX7A in V2 With TAD E83cc. RCA was microphonic. Tremolo RCA jack wasn't making good ground contact. Removed and cleaned chassis and jack with DeOxit. Tremolo is in operation mode with RCA jack ungrounded. Cleaned and grounded RCA plug turns it off. I had always used a footswitch to operate tremolo ,and was mistaken about it's operation. I acquired this amp in 2000. It was found in the garage of a rental house, that had been used to paint cars. Amp had been on fire, output transformer was dead, cloth covered wire jacket was crumbling, Blonde Tolex was painted black. All wire was replaced with appropriate cloth covered wire, output transformer was replaced with an Allen amps trans. All electrolytic caps replaced, Tolex cleaned. Chassis was already punched for a rectifier tube. I added a 5U4 to lower B+ voltage. The amp is certainly not a collecter piece at this point, but the harmonic vibrato is wonderful.