Gut and rebuild a 1960 Ampeg Rocket?

[olddawg]

Ok folks, so I have a really ugly but solid 1960 Ampeg Rocket (made in new Jersey btw) that I literally pulled out of the trash a few years ago. It does not have the original back panel. Someone spray painted the grill cloth gold and the tolex is really rough and duct taped up. I replaced the filter caps and it works. I blew out the original Jensen in about 10 minutes. I have an Eminence in it now. It has 6v6 outputs. I don't like the way it sounds. I'm thinking about rather than specing out all of the components and really fixing it that I might gut it and make it into a Marshall 18 watt variant. It's too clean and I don't like the way it breaks up. It wouldn't be hard to drop another turret board in it and there are 1974 variants that use 6v6s. Or I could fix it up stock, sell it and get something else. Almost bought a Vox Night Train today for $300. Any thoughts?

[Chuck H]

Ampegs were always in sort of their own class and school of thought. That said... It's hard to say that the results would be predictable just rewiring it to a known circuit from another MFG. If you know the B+ and OT pri Z specs that will help though. Layout??? Gut shots.

I'm not in league with the idea that an "18 watt" type amp can be built with 6V6's. Only because you simply can't drive them as hard as EL84's are driven with the same basic topology. So it must invariably become a different amp. That isn't to say that you can't build a rocker from 6V6's. I love 'em. But after spending A LOT of time working with EL84's I just don't see where an 18 watt type design can do it with 6V6's.

I might opt for something like a TW Express type circuit that is known to get good OD and acceptible cleans from those tubes. Or if OD isn't your game then a typical BF type circuit is always good with 6V6's for clean. This does somewhat depend on the iron and layout your forced into by building on an existing chassis.

[soundguruman]

The rocket is a cool amp to modify, too bad somebody spray painted it. The design of Ampeg is basically clean, low gain, and so Gut the thing by all means.
I think you could probably get some retro grill cloth from Antique Radio Supply in Arizona.
The small size and retro design is very hip these days. I think I could fit Marshall 50 transformers in there (and I would probably do it too).
But for sure one of the coolest looking chassis and cabinets, ever. It ranks right up there with Valco, Oahu, ancient Rickenbackers...in coolness factor and mojo quanta.

[Bruce / Mission Amps]

...I'm not in league with the idea that an "18 watt" type amp can be built with 6V6's. Only because you simply can't drive them as hard as EL84's are driven with the same basic topology. So it must invariably become a different amp. That isn't to say that you can't build a rocker from 6V6's. I love 'em. But after spending A LOT of time working with EL84's I just don't see where an 18 watt type design can do it with 6V6's. ...

I've built lots of fixed bias 6V6 amps with two power tubes and two preamp tubes, hitting a dead clean 20-22 watts into a dummy load from 83Hz to +4KHz.... so, I must not fully understand what you are saying.
Are you saying you can't build an 18 watt 6V6s amp from this chassis or a preamp designed for EL84s can't drive 6V6s into full power?
6V6s can and do take a lot more grid drive signal then EL84s and bias at a much deeper grid to cathode voltage... so, please clarify this for me.

[Chuck H]

\6V6s can and do take a lot more grid drive signal then EL84s and bias at a much deeper grid to cathode voltage... so, please clarify this for me.

That's it exactly. The actual "18 watt" schematics generally have one triode feeding a PI. You'll never get the drive voltage to send 6V6's into square wave wanker tone that way. But EL84's are much easier to get crumbling.

I wasn't at all saying that a pair of 6V6's won't make 18 watts. And FWIW the only reason I'd been working with EL84's is that I was designing a budget minded project and they're cheap. Overall I prefere 6V6's. After working a while with EL84's I have come to appreciate their unique distortion character though. My current personal amp is a prototype from that design process.