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V4B reissue .. fan free?
- Thread starter kd5uwl
- Start date
I foresee less money in your bank account. 
It's a very nice, well designed amp. It will be a classic down the road.
It's a very nice, well designed amp. It will be a classic down the road.
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Again, thanks for the help regarding this amp. One more question .. no way to bias the tubes myself?
I like the external adjustments and indicators on my svt that let me change and re-bias the power tubes.
How do you handle this on this new V4B?
As an electronics hobbyist comfortable in high-voltage tube circuits I have a meter and other test gear .. I suppose I could do it if there are test points just inside and a published procedure .. ?
I like the external adjustments and indicators on my svt that let me change and re-bias the power tubes.
How do you handle this on this new V4B?
As an electronics hobbyist comfortable in high-voltage tube circuits I have a meter and other test gear .. I suppose I could do it if there are test points just inside and a published procedure .. ?
Suggest you read the long-running V4B reissue gas-inducing thread. It will answer all these questions and more...
There is a pot inside the chassis for setting the bias. Ampeg has posted the V4BR bias procedure. It is intended to be used by a qualified person.
Ok, so I have my V4B reissue now. Compared to my 2011 Heritage SVT the bias was much more difficult to do. With the SVT the pots are on the back with visual indicators.
But with the instructions you provided, beans-on-toast, it was quite doable. Definitely a job I'd not recommend for anyone but a qualified technician .. you could hurt or kill yourself in there.
Here is a tip - the chassis is on a shock mount system inside the case and arranged such that the tubes hang upside down. And it has to be in that orientation I get the chassis cover off and make the required measurements and adjustment inside.
So I "built" a "jig" .. consists of two landscaping bricks three or four inches on a side which is enough that the mounting rails can sit on the bricks which elevates the transformers and tubes above your work surface.
I wrapped my bricks with Kraft paper (cut up grocery sacks) to make a nice neat package that wouldn't scratch the rails.
This worked well.
But with the instructions you provided, beans-on-toast, it was quite doable. Definitely a job I'd not recommend for anyone but a qualified technician .. you could hurt or kill yourself in there.
Here is a tip - the chassis is on a shock mount system inside the case and arranged such that the tubes hang upside down. And it has to be in that orientation I get the chassis cover off and make the required measurements and adjustment inside.
So I "built" a "jig" .. consists of two landscaping bricks three or four inches on a side which is enough that the mounting rails can sit on the bricks which elevates the transformers and tubes above your work surface.
I wrapped my bricks with Kraft paper (cut up grocery sacks) to make a nice neat package that wouldn't scratch the rails.
This worked well.
The first time people do a job like this it can be pretty intimidating. Being a bit on edge when there is the potential for getting bit is a good thing. An amp cradle helps keep the workspace safe.
Sounds like you did pretty good.
Sounds like you did pretty good.
Ya, good job. Frankly, I'd never try it myself, but the jig to hold the chassis that way is a good tip.
Here is a V4B on a cradle that they use at Loud. Makes working on an amp a lot easier and safer. No smashed tubes.
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That photo of the chassis on the cradle is giving me GAS. This is going OT, and I'm sure this gets asked every couple of days, but has there been any discussion of a "Heritage" model built in the USA (or other nominally first world country?) I went w/ the Aggie TH500 in large part due to the "made in NYC" stamp. Has Ampeg had enough success with the other Heritage models to consider a V4b version?
I don't see a Heritage V4B happening. It is very well designed and the board layout is modern. In the case of the SVT CL, the board design goes back to the SLM daze. It is hard to improve on an amp that is so well done. I suppose that they could offer NOS US made tubes and (Heyboer perhaps) transformer set.
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Heritage V4B is not currently in the cards. From what I hear, I doubt it will be unless sales end up being legendary. But you can buy the grillcloth and make your own 
