Peavey VB-2 All Tube Bass Amplifier: Repair/Restore & Modifications

@Peavey Electronics

Hey Everyone. This video shows a teardown and repair of my VB-2 All Tube Bass Amplifier. This originally had the stock JJ tubes still in it. While it was working for a time, one of the power tubed arced and another red plated. Unfortunately the tubes have seen their share of use and it was time to change them.

Wanted to give a big thank you to John Fields and Bobby Baldwin for all their technical knowledge, advice, suggestions, and support on the electronic repair. This is my first time repairing a tube amp at this level. It can be extremely dangerous working on tube amps due to their very high voltage inside. If you are not comfy with this environment, hire a professional tech. Noone wants to be electrocuted by the HV and injured or worse killed!

The amp is from 2007, and like any tube amp, needs a fair bit of service to make it road worthy for another 15 years worry free. The tube socket pins needed to be re-tensioned, cleaned, and all the 1/4" jacks cleaned with Deoxit Gold. The tone pots are sealed and should not need cleaning, thankfully mine did not. Also went through the tolex which was not too bad at all, but reglued the areas where it was peeling away and fixed the tears so they would not get any larger.

When the tubes failed it also took out F2, which is the high voltage fuse. This seems to be a common issue with this amplifier blowing out F2. The reason why is because the original value was a T1.5A 4.5x15mm axial soldered fuse, but it was later changed to be a T1.6A. Seems this fuse was changed out at one point before I bought it, but it still had the original T1.5A. In order to pass safety regulations at the time, Peavey had to use the board soldered axial lead type. This made the amp harder to repair since you need to remove the preamp board in order to access the fuse to replace it. The mod I show here takes F1 (F1A type) and F2 (T1.6A) and puts them in accessible fuse holders at the more standard 5x20mm size. Now I no longer have to remove the preamp PCB to replace them.

For good measure I also double checked the "flyback diodes" on the output transformer primary windings to make sure they were still good. This could be another failure point when a power tube fails. It's important to test these diodes after isolating the winding of the OT, and power up the amp without any tubes in it first. If the diodes are bad, it would pop the HV fuse immediately.

I went with a matched set of Electro-Harmonix Big Bottle 6CA7s, two 12AX7s for the preamp, and one 12AT7 for the phase inverter tube. Power tubes are biased to 26mA per tube at the recommendation of John Fields. You need a proper bias probe to measure this. The onboard test points only measure the bias voltage, which tells you NOTHING on how hot your tubes are running. A bias probe is the right tool for the job!

I learned a lot from this project. I'm grateful to own this amp as it is becoming harder to find, and it is now fully restored to gig with again! I have not seen too many videos on YouTube about this amp in recent times. It really is a well built amp, sounds amazing, and one of the last amps made in the USA by Peavey.

Any questions or comments please leave one below. Thank you for watching and supporting my channel!
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