6U8/ECF8/6F1 tube as reverb driver/recovery

[Tqi]

Pretty much that.

Could one use the triode and pentode sides of this as a reverb recovery and an SE reverb driver stage, with something like an accutronics tank?

If you're not familiar with them, they're a triode and pentode sharing a Noval package, originally designed for TV use and also the Vox AC10 preamp.

[Tqi]

I tried some different search terms and this is absolutely a thing.

A transformerless reverb driver - Tone Snob
Channel Road Amplification: Transformerless Reverb Driver
http://music-electronics-forum.com/t7229/

Oops.

Anyway, just to fill in the absent background... as we all know, the best amp ever made is a hybrid Fender called the 'Vaporizer'. Tube power and PI, switchable tube fuzz, solid state reverb driver and a hybrid TL072 and 12ax7 pre-amp. The schematic is like something out of a string theory paper.

Anyway, I decided to try and understand it again, now that I have a bit more understanding of amplifier design, and it's actually deceptively simple, once you pull the weird fuzz circuit out.



Now, despite many unkind words said on the internet about the TL072, the amp is almost silent when the reverb is off; and I believe the general consensus is that the reverb circuit is just badly designed. I started thinking about how one would fix this; then realised that any 'fix' to an existing board would be many effort for little payout, and that the best use of that time and energy would just be a straight rebuild.

Just doing a simple substitution with 'obvious' replacements ended up very tube-heavy, given the relatively high number of gain stages; but I took a look at the 6G15 and noticed that the actualy driver/recovery circuit of the amp is just one triode and one pentode. And that's what lead to this question.

Have three of these amps, adore them just as they are, but it was a fun thing to think about. The 'what if one dies' scenario. That said, if someone offered me a Vaporizer with a bad PT for €70 or something, I'd totally do this. Keep the OT, replace the PT (Lose the 15V winding, more current for the extra tubes) and rewire on eyelet for an all-tube version with ECC83, ECC83, ECL82, ECC83, EL84 P-P.

[Leo_Gnardo]

Geez I thought I'd seen 'em all, this "Vaporizer" is a new one on me. A far as transformerless reverb drive, Ampeg started doing it in 1962, and onwards thru the 60's & 70's in lots of models. They didn't go "one tube" reverb, nonetheless those amps are living proof you can drive a reverb with a sturdy little triode, and most folks think those old Ampegs' reverb sounded mighty sweet. One question about the Vaporizer, would it help to schmear Vicks Vap-o-rub all over my chest whilst playing one? Y'know, for the full effect?

[Tqi]

No, but one should always play it with brylcream or pigtails, a thick milkshake and a hot rod parked outside.

[Leo_Gnardo]

No, but one should always play it with brylcream or pigtails, a thick milkshake and a hot rod parked outside.

Now that I googled a couple of photos, I see what you mean. And the prices vary from $200 to $899, that's bizarre too.

All I have to do is wait to see one in person, someone will eventually show up with a Vaporizer in need of repair.

[Tqi]

And the prices vary from $200 to $899, that's bizarre too.

I'd describe it as 'optimistic'. The amp was about $400 new, which was fair for what it was: a decent 2x10 valve combo with some DIP IC's and no digital not even the reverb. These days about $200 to $250 seems the going rate. I'd only pay about $100 for one, but that's because I already have all three, and I'd only be buying a fourth to gut it.

All I have to do is wait to see one in person, someone will eventually show up with a Vaporizer in need of repair.

Probably! It's one of 'those' amps, like the Excelsior, Valvetronix, D-Lux (Type 109). Cheap, sturdy - but when it goes wrong...