Billy Zoom's Jet Set

1AB2B1B in 6g15?

1

I thought you'd know Billy, but I'm interested in everyone's thoughts on this.

I'm looking at building a valve reverb kit. I can get one cheap without the chassis, cab or tank. I've got a couple little practice amps I could use the cab and chassis from. I just don't have anything big enough to fit a 17" reverb tank.

My question is, would I get a decent enough sound out of the shorter 1AB2B1B tank? Or would it not be worth the bother to put together a valve unit, and then skimp on the actual reverb tank size?

2

I have the shorter 3-spring pan in my Champ, and it sounds really good. I haven't tried it using a MOD pan yet, but that should be even better, judging from their longer pans.
BTW, the Champ became the Ham Reverb because the extra knobs covered up the C, so I eraced the P because hamp seemed wrong. Maybe it makes more sense if you see it. Anyway, it sounds good, but go with 3-springs if you use the short ones.
If you want to try adding reverb to one of your little amps, look at the way Fender added it to the Princeton Reverb.
The 6G15 isn't really a great sounding unit. There have always been issues with what happens to the dry sound when you turn the mix knob off of zero. I think people are sort of used to it, but you can do better. The drive circuit was much better on those Silver-Face Reverb units, but I don't know where you'd find a transformer. The secondary has to bias the triode-wired 6V6, and the 6G15 driver transformer won't work in that circuit. I'll have to measure that Xfrmr the next time I have one in the shop. They just don't come around that often. If you do build a 6G15, use the newer bridge rectifier circuit. It raises the hum an octave so you don't need the 40mfd. filter caps.

3

Thanks for that man. You now have me reassured that it's ok to use a shorter tank, and also pretty sure I'm not gonna build a 6g15 with my hack skills.

4

Triode electronics sells this reverb transformer for on-board reverb circuits. I can't tell you if there was any difference in the on board reverb transformers over the years.

http://triodestore.com/40-1...

Rocco

5

That's for the 12AT7 circuit. He was talking about building a stand-alone Reverb.

7

Yes, all of the transformers are easy to get except for the Silverface type. I just think that's the cool one if you're want to copy a Fender circuit. As I said before, I don't care much for the Fender reverb units which is why I designed the Little Kahuna. I thought somebody should make a better one. Why did you use a Belton tank instead of a MOD?

8

I got all the parts from triode, I was making some tweed cabs for them at the time and traded. But I have a MOD tank in a Teisco Checkmate18 that I modded the circuit for, sounds pretty good. Using a 12dw7 for in and out, no transformer. Basically an Ampeg circuit.

But I agree, that the Beltons do not sound as good. And the fender circuit can get a little bad sounding when pushed the wrong way, especially with the Belton tank. The Ampeg circuit otoh, can be quite fun with trem depth at 10, speed all the way down and lots of verb. I've currently got a 500K linear pot on the drive side screen to ground, and a 500k audio on the verb knob. Can't decide whether to keep the Dave side knob on, or set it permanently.

Now what about that modified reverb circuit for the Silvertone 1474? Mine is a very early model with the 3 knob reverb. Hint, hint , hint.

And one more thing, I forget the name now, but the former Accutronics folks in Cary, Illinois are making the original style tanks again.

It might be these: http://amprepairparts.com/r...

Rocco

9

I think revisit, mod are the same mfr, might be mojo too.

Rocco

10

I have a sneaking suspicion that the MOD pan I use in my F-Bomb tanks (6G15 redefined), which I find closest to my original Gibbs pan (also the longer decay isnt my favorite and I modify that) is probably making the ruby, the mojo and even this revisit pan you shared Rocco. I would seriously love to find out if the gibbs pan IS indeed being redone because even my original accutronics pans dont have the drip/dimension of my gibbs. BTW.. I dont want to put words in Billy's mouth but in his sharing that he prefers the silverface tank to the 6G15 original, I'm pretty sure its the change they made to improve the guitars original signal through the unit that makes it sound better because a stock 6G15 isnt kind to a gretsch guitar signal in my opinion its too warm and bloated.

11

The mix control ruins the dry tone on both of them, but I like this drive circuit better. It's hard to damp a reverb signal. Regular feedback won't work because there is no phase to the signal. The impedance variations of the reverb pan really need some kind of damping.

13

is this incorporated into your Kahuna? if so then it makes sense how it sounds so nice.. at least the times Ive had the chance to hear it at Toms booth. Why do you think the surf guys want to stick their nose up at the silverface tank, is it a lemmings thing? :)

14

Never knew there was such a big difference in the Fender silverface unit, but until someone explains why they did what they did....I'll be happy with the fact that I can't play well enough to justify anything I do. But this stuff is fun to play with.

I will have a Kahuna once I get the extra change gathered.

15

Lemmings don't play guitars. That's their problem. There are lots of cool things that most players will refuse to listen to. That's why I was able to afford a 1955 Silver Jet in the seventies. It was $35 because nobody would even try it because it was sparkly and a Gretsch. The music store wouldn't even hang it on the wall. It was in a pile on the floor in the corner, along with Danelectros and Goyas. No cases, just a pile of what they considered cheap novelty guitars. Somebody famous has to say he used one and then eveybody will have to have one. I guess it is a lemmings thing, but lemmings was a really funny album.

17

Why did Fender opt to use a half way rectifier in the original stand alone reverb?

I noticed that my own Fender tank, a reissue rewired masterfully by Billy Zoom, has a full wave rectifier. Sounds awesome.

My Gomez G-Spring tank has a half wave. There is a tonal difference between the handwired Fender reissue. While I don't mind having two flavors of reverb, I'm starting to wonder if it would be worth modifying the G-Spring?

From my own research, the original half wave rectifier produced choppier DC voltage that required more filtering. I've also read that this type of rectifier produces more heat.

Thoughts?

18

Because it cost a nickel instead of four nickels. Don't overthink it.
Silicone rectifiers were new and the price hadn't dropped to two cents yet.


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