Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: goldtop1 on April 14, 2012, 11:05:00 am

Title: Doug's AB763 Tremolo{here we-go}
Post by: goldtop1 on April 14, 2012, 11:05:00 am

Hey guys, I sure have learned a lot from this forum. I read and gather all the info I can, then try to troubleshoot and fix the problems. I took a 1974 Twin reverb and completely gutted it and installed Doug"s AB763 board to make it to Blackface specs. All new everything except the OT,and choke. I even took the doghouse away and installed the filters inside the amp. The amp sounds much clearer than the original Silverface. After finishing the project the reverb is great, tremolo is OK probably better if I would bias a little colder. My question is why does the tremolo work without the switch being shorted to ground? I did disconnect the wire going to the switch, but it continues to run. I have troubleshooted everything I can think of. Do you think there is something grounded somewhere? I also tried different tubes  to no avail. It's probably a simple solution, but sometimes the trees get in the way of the forest! What a great website here, a wealth of knowledge! :help:

Title: Re: Doug's AB763 Tremolo{here we-go}
Post by: sluckey on April 14, 2012, 11:20:04 am

That's the way Doug's trem circuit is supposed to work. There's nothing wrong with it. Don't fix it anymore. The trem is not the AB763 variety.

http://home.comcast.net/~seluckey/amps/misc/Hoffman_AB763.pdf (http://home.comcast.net/~seluckey/amps/misc/Hoffman_AB763.pdf)

Title: Re: Doug's AB763 Tremolo{here we-go}
Post by: goldtop1 on April 14, 2012, 01:54:24 pm

Thanks Sluckey for the info worries gone for now! Cheers! :occasion14: