Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ratgon on April 07, 2026, 09:38:27 pm

Title: Help with Vibrolux Reverb
Post by: ratgon on April 07, 2026, 09:38:27 pm

Hey all and thanks for your time. I've been building a VR, and it seemed to be going well, but as I've started up the initial power-up procedure, I'm running into issues. The negative bias seems to be working fine but I can't get any voltage on the plates. At times it comes up and then it's gone. I'm rebuilding the filter lineup in the doghouse, so we'll see, but I can't see how no voltage is getting to the plates unless it's a screwed up OT. How can I check for that?

I'm open to any help at all. I'm all ears and ready to learn. If there are any oics that would be helpful I'm happy to post them for you.

Thanks again,

Mike

Title: Re: Help with Vibrolux Reverb
Post by: glass54 on April 07, 2026, 10:10:24 pm

Schematics as built? Maybe a photo? :rolleyes: :smiley:

Title: Re: Help with Vibrolux Reverb
Post by: stratomaster on April 07, 2026, 10:48:03 pm

Take the tubes out and do a full voltage survey.

Title: Re: Help with Vibrolux Reverb
Post by: pdf64 on April 08, 2026, 02:23:49 am

Providing photos and a link to the schematic and layout that you've used to build the amp would be a good idea.
Here's Fender's original, but I assume youve built it from a kit  :dontknow:
https://el34world.com/charts/Schematics/files/Fender/Fender_Vibrolux_Reverb_AA964_schem_layout.pdf

Title: Re: Help with Vibrolux Reverb
Post by: ratgon on April 08, 2026, 09:22:05 am

I used that exact schematic and layout - AA964. I didn't build it from a kit. I just slowly assembled all the parts. I'll send some pics as soon as I'm done rebuilding the filter caps and hooking them back up to their proper points. Thank you for your patience