Gretsch Amps

Gretsch reverb units

1

Hey guys. Gonna build a Gretsch reverb unit to compliment my new Model 24. Wondering if anybody would have a schematic for the unit that had an 8" speaker built in, with the boomerang Grillcloth? Also interested in which reverb tank would I use for a model G6144 reverb unit. Same as a Fender? Sure appreciate the help.

2

Is this the amp you are referring to with the boomerang grillcloth? It has a 12" speaker and no reverb. It is the G6156 Playboy.

3

No, the reverb unit looks similar, but is much shorter and has an 8" speaker. It slaves out to any amp. It can be seen herehttps://www.youtube.com/watch?v=NksFV54pu4A

4

The Gretsch and Supro standalone reverb units are almost exactly the same. But instead of driving the reverb tank with a transformer (ala Fender) they use a 6DR7 tube. Just wondering what kind of input impedence value I should be looking for when shopping the reverb tank.

6

Just wondering. What is the purpose of the 8" speaker?

7

General, it's not a reverb unit like a Fender. Think of it as something like a Fender champ that's a Reverb amp - as in reverb only. Concept is not as crazy as it sounds, and actually works pretty well. It takes a signal from your speaker output on the amp you're plugged into.

8

The amp sound is still dry. The Reverb sound only comes through the 8" speaker. This was common for a few minutes in the early/mid-sixties when nobody was sure yet how to best use the Hammond spring units. Fender of course set the rules and everyone else eventually followed. It's just a little amp with a spring in it that runs either parallel to the big amp, or sometimes takes it's signal from the big amp's speaker. Do you have the factory schematic? There may be some impedance clues that you haven't noticed. FWIW, some of the Valco units had the little cardboard box spring units that were made for rear deck speakers in cars. They didn't sound very good though. You might be better off just building a cool Gretschy cabinet and then making up a circuit. You could certainly do much better than the original unit.

9

Hey Billy! I'm building the reverb unit to go with a Supro Model 24ish amp I built for a guy in the UK, a rockabilly guitarist and also a killer graphic artist. He came up with the look of the amp, which is in a stylized Gretschy cabinet. I think I'm really going for a 60's, cheap trashy LO-FI sounding reverb. Not going as far as using a cardboard reverb tank, but I've got a dozen old Gibbs-Hammond tanks. The only schematics I have are the Gretsch G6144 and the Supro one drawn by Howard Dumble, which use a tube to drive the tank instead of a transformer.

10

Those Playboy amps are the baddest things ever to look at, heard they sound excellent too.

11

If you need any help with circuit desgn, let me know.

12

Those Playboy amps are the baddest things ever to look at, heard they sound excellent too.

– david burch

David, as good as the Playboy sounds, the Executive is even better. It has both tremolo and reverb, whereas the Playboy only has tremolo. And, it has a 15" speaker, compared to the Playboy's 12" speaker. Their outward appearances, however, are the same (except for size, obviously).

14

Well, after pouring over many posts, reviews and opinions regarding reverb units, I've decided to build a Premier 90 clone. Since I really don't want to reinvent the wheel, and so many guys seem happy with their cleaned up units, I'm just gonna start from scratch, use the original tube line up and concentrate on better materials and build quality. Luckily, I have a pretty nice stockpile of Hammond/Gibbs tanks and transformers from AO-43 amps, which were driven by 12BH7 tubes (12 AU7 relative) instead of the 6AQ5 pentode. Not sure how that will translate yet. Should be a fun ride!

15

The great thing about building a Premier 90 clone is that, no matter what your skill level is/isn't, you're virtually guaranteed to have a nicer build than the original.

6AQ5 tubes are cheap and plentiful NOS. Why not use them?

16

David, as good as the Playboy sounds, the Executive is even better. It has both tremolo and reverb, whereas the Playboy only has tremolo. And, it has a 15" speaker, compared to the Playboy's 12" speaker. Their outward appearances, however, are the same (except for size, obviously).

– Ric12string

Right on Ric. Thanks to your opinion when I asked for advice for a great amp for that Chet sound, I found a mint Executive and it's fabulous. I haven't played the Playboy as this Exec is the only Gretsch amp I've seen. Sure they're pricey, only available used but usually by half as much - but a hell of a lot cheaper than a new Vicoria Regal or a Standel, their only real comparables for speaker size and clean sound. I know Fender makes a terrific 15" speaker amp with the Twin Custom 15 but it's very heavy and has far more output than most 'clean' players need, particularly fingerstyle artists.

17

Don't use that center tap with a bridge rectifier. I guess you figured that out. You should make a little guitar amp with that AO-43 transformer. It's push-pull using both halves of the 12BH7. They sound pretty good.

18

I have an original, unmolested Premier 90 that I'm gonna use to measure voltages. Then I can experiment with a bridge recto, full wave recto using 2 x 1N4007 diodes and even a tube recto (EZ81) to see which gets me closest to the original. I like the tube recto to slow down inrush current, but expect a 10 volt drop. I really want to stay as true to the original as possible. I agree with you about the AO-43 iron. I've built a bunch of 18 Watters and Princeton Reverbs with those two transformers, and the little 12BH7 push pull amp. Once I get some measurements, can I PM you my schematic? I'd sure like to hear your angle. Thanks Billy.

19

It's too hard to find good EZ81's.

20

I agree. Once I get this thing ironed out I'm only planning on making half a dozen or so. I have a nice little stash of Mullard and Amperex EZ81 rectos pulled from Hammond amps, as well as NOS 6EU7 and JAN 6005w tubes. Certainly enough to make my run. NOS should be good for 40 years or so. Just want to explore the tube recto out of curiosity. The prototype chassis already has a couple needless holes. What's one more!

21

Well, the P-90 is up and running. In a side-by- side with my original unmolested 1967 P-90, my unit has all the nuances of the original without any of the bugs. Very quiet, even with Intensity up and the Volume in the gainy spot. Tonally nothing like a Fender, but still over-the-top reverb effect when turned past 4. Using a correct Gibbs type R tank (8 ohms in/2250 ohms out), I'd like to dial back the reverb drive so I can use more of the intensity sweep. I guess I'm gonna rewire the 6EU7 socket for a 12xx7 tube and experiment with those to try and decrease the recovery stage, get a little more headroom. Otherwise, very cool little unit!

22

Wondering if you could send me a copy of your schematic/layout? I've been working on one for a while now and cannot seem to get it not to hmmmm.

23

I have a reverb unit by "Fox Vintage Amps" that's loosely based on a Premier 90 - it's a lot cleaner and smoother though. He used a Fender reverb unit chassis and 12AU7 and 12AT7 tubes, and Fender transformers. I have the schematic and/or layout somewhere, I'll have a look and if I find it, I can scan it if you want. It has a three spring tank in it now, and it's a little too smooth and underwhelming now - I've ordered a two spring for it.

24

That would be awesome

25

Hey Jhtjon. I'm drawing up my final version now, and I'll post it for anyone interested. Mr Fox is pretty tight with his schematic, as I think he's thinking about making more. Might wanna ask him outa respect. My final is low voltage, original spec reverb pan, still has the gain bump as the original. Mr Fox's version is polished and refined. Mine sounds grittier, like 1962 New York subway tunnel echo. Running a 6AQ5 and 12AT7, definitely more latitude on the Volume and Intensity controls than a Fender. Schematic and pics to follow.


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