Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Big chief on January 29, 2021, 12:03:07 pm

Title: Ampeg B12-XT
Post by: Big chief on January 29, 2021, 12:03:07 pm

Tremolo switch appears not to be working voltages are all within limits
Replaced bypass caps
All tubes tested good
Can you wire around the VM-1 switch as I cannot locate one on the internet

Or any suggestions

Thanks

Title: Re: Ampeg B12-XT
Post by: PRR on January 29, 2021, 10:16:16 pm

For others:
https://drtube.com/schematics/ampeg/b12xt.gif

"VM-1" is the "roach" center top. Routes to "Z" top and a bit right of there. Snipping "Z" should kill all trem action yet still pass signal. A NE-2 neon and a couple LDRs might be a DIY roach.

Title: Re: Ampeg B12-XT
Post by: Latole on January 30, 2021, 03:55:01 am

Not sure I understand what you need.

Most of the time for tremolo issue, I replace all coupling caps, not bypass caps. And each time it work

Title: Re: Ampeg B12-XT
Post by: sluckey on January 30, 2021, 08:09:18 am

Quote from: Big chief on January 29, 2021, 12:03:07 pm

Can you wire around the VM-1 switch as I cannot locate one on the internet

VM-1 sold here...

     https://www.fliptops.net/catalog/p-100088/vibrato-module-vm-1-gv-and-x-series-amps

Title: Re: Ampeg B12-XT
Post by: Big chief on January 30, 2021, 10:26:17 am

Thank you very much