Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: LooseChange on June 21, 2010, 06:37:12 am
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Your basis tremolo circuit from the Fender AB763.
Changed the roach and the 3 caps and the tube. Everything appears to be in workinging order but the tremolo is weak. Have I missed something? Is there a way to make the tremolo stronger.
The tremolo does not come on very quickly either.
Thanks!
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There is still something wrong.Those trems are as deep as can be when working properly.
Triple check against the schematic,taking note of voltages.Double check the bias supply as a feed wire goes to the top of the trem caps.
It it takes a moment to engage,you have a ground or cap charging problem.
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There's an old thread in the Archives about tweaking the 6G16 bias-vary tremolo, but you may be able to apply some of the concepts to the roach-style tremolo:
http://www.el34world.com/Forum/index.php?topic=604.0
Is there a good way to test how well the roach is working? IRRC there was a thread here about that not too long ago but I'm not sure. Just because it's new doesn't mean it's good :wink:
Cheers,
Chip
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> Changed the roach and the 3 caps
Change the cathode cap. Also the cap out to the Depth pot.
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I'll do that but there is no cap to the Depth control.
I read in Jack Darr's book that the large resistors have to be very close to spec and that drifting up will make a difference.
Thanks!
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If the cathode cap doesn't do it, try another roach. Is this an old Fender amp? If so, you may have conductive fiber board issues.