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Discussion in 'Amp Central Station' started by dannyh, Mar 2, 2017.
So, it seems you had more than a few "12's" in your head at the time.
I don't have anything useful to say about 6SL7 or 6SN7 tubes (or this specific Ampeg design), but I do currently use a Hohner amp that's Ampeg-ish (2 7591s, a Baxandall tone stack, a 6CS7 tube) and I've got new JJ 7591s in it now. If a pair of NOS 7591s fall into my lap, I'm certainly going to give them a try, but I think the next set I buy will be the EHX. I've had good luck with the EHX 12AX7s.
I'm way into the amp, you can dial in a good sound with any guitar I've tried, and it stays pretty clean all the way up. If I jumper the trem/reverb channel with the 'dry' channel, it gets a little bit of grit going, but it responds beautifully to the Rangemaster or OD-250.
If you can get that Reverberocket for a fair price and are interested in having something that's not a "classic Fender or Marshall design" I'd say do it.
Well I pulled the trigger on the amp. Thanks again for all the input. Look forward to getting this thing rolling again.
Different model, but I was just browsing YT and came across this. I think it's an excellent walk through for troubleshooting an old Ampeg.
Am I wrong in thinking that this amp can take 6V6 after rewiring the sockets? That was always my impression - that the 7591 were substituted for more clean headroom.
BTW - the 6SNL and 6SL7 are considered mainstream tubes in audio - not rare or unusual at all. They can be microphonic in guitar amps - but so can 9 pin miniatures.
I have heard that before, I have no firsthand experience though.
I'd recommend giving the 7591s a shot before changing the socket wiring, you just might like it. For a long time there weren't any current production 7591 tubes, but now you can get new JJ, EHX, and Tung-Sol. It may be the case that I don't know what I'm missing re: NOS 7591s, but I'm willing to leave that filed under "known unknowns" until some Westinghouses fall into my lap.
This will be my first 7591 amp, so I'm going to run it stock to begin with. I've heard some you tube clips (grain of salt) that I liked the sound of, and I already have several 6V6 amps.
At this point I'm actually more concerned with what preamp tubes to get for it as I've heard the octals are very prone to being microphonic. Ive heard good things in that regard about the new Tung Sol 6sl7's and 6sn7's and even found one place that offered "low noise/low microphonics" for a surcharge (perhaps more grains of salt required here?).
Its almost as if NOS is not the way to go as far as the preamp tubes go, or so I've read in some other forum posts lol....still trying to decide which way to go.
I just put a pair of Tungsol 7591s in my '65 Reverberocket 2. They sound great. Cost me $60.
Yes, the amp can use 6V6 tubes after rewiring the sockets and changing the 140 ohm cathode resistor to a 250 ohm. This was something that was done in the late 70's into the 90's when finding a good pair of 7591's was not cost effective. I'm not sure why anyone would go through the trouble, these days, with JJ and Tung Sol making a 7591.
I've never heard the new production 7591 but I have and have heard a lot of NOS 7591s and I think 6V6 and 6L6 are better sounding guitar tubes.
That said, knowing how tube makers do, I wouldn't be at all surprised if the new 7591s are just re-pinned 5881s or 6L6s.
I agree however that trying the new 7591's is the easiest path forward. I am planning to try some old 6L6G (max voltage 370) in my reverberocket, when it is fixed.
Congrats on the amp!
I've had a Rocket II, Gemini I and currently a Gemini V. The V is the same as the II but I think it's the first year under new ownership('67) but I'm no expert. Selling that Gemini I was likely the dumbest thing I ever did.
Keep an eye on ebay. I got a nice pair of Ampeg branded, Sylvanias I think, 7591 for $70 a couple years ago.
This could be a great lot:
I have 1 tested good Ampeg labeled 7591. $30 to anyone who wants it!
I've played through and repaired every version of the 60's Reverberocket made. I think it would be real hard to tell the difference between the version with 6V6's and 7591's. The real difference, in the early models, was the use of a 5Y3. This led to more compression and sag, which had nothing to do with power tube choice. The short lived R12R-A had 7591's and a 5Y3. It sounds pretty much the same as the 6V6 version. The 60uf filter, used on the first node, proved too much for the 5Y3 rectifier. Ampeg updated the circuit to the R12R-B and used diode rectification. All these amp run the power tubes in a cathode bias circuit with about 360v on the plates. The later top loaded models, R12R-M and R12R-T do have a bit more volume, punch and are tighter due pre-amp tube choices and the diode rectifier. The tone, as far as I'm concerned, is the same. The R12R-M pre-amp used three 12ax7's and a 12au7 with a opto-coupler trem circuit. The power tube were 7868's; which are a noval pin version of the 7591. The R12R-T used a 6BK11, 6U10 and a pair of 12ax7's with a pre-amp tube oscillating trem circuit and a pair of 7868's. The lower loss trem circuit in the R12R-T makes the amp louder than the R12R-M and is my favorite of the original top loaded Reverberockets. YMMV.
It's cleaning up pretty nicely. I'm getting the "tolex" and grill cloth cleaned up a little, and will probably take the chassis to the amp Doc early next week. I've got a couple Jensen Neo 12-100's and a Eminence Special Design out of a Blues Jr; I'll probably stick one of those in til I figure out what speaker I really want. I'm kinda leaning towards a WGS G12C, as I really like everything Ive tried from WGS, I think the brighter G12C might be better fit for this amp than say an ET65 (I have two of those already), and I've got another couple of amps the G12C would probably be a good fit for if for some reason it didn't get along with the Reverberocket. We'll see.
Here's a couple of progress pics...
Great. For my money, that blue check Tolex is the coolest ever designed.
I'm left wondering how I missed this great thread.
I am a little bit torn over a 1962 Reverberocket I located. My curious ears want to hear it. My restless left half brain, wants to tinker in it and service it. My heart wants to rescue it and love it by playing it often. My conscience tells me maybe I have enough vintage amps. My ass wants to stay sitting on my wallet, and not open it up. Lastly my fingers want to feel that cool checker pattern tolex. It's $225 US funds plus shipping. It looks pretty good. Needs service. Won't make noise. I do my own repairs at home. What say you folks? Some quick research tells me these Reverberockets are undervalued among the tube amp world. I have no experience with these amps. I do have a 1972 Ampeg V4-B. That's my only experience with Ampegs. I'd love to hear your comments. Thx.
If it looks good and you know how to work on them, then $225 is pretty fair. If you feel you made a mistake, just get it working and sell it for at least $100 more.
Keith If it was near me for $225 I'd go get it. And I've already got two 62 Revererockets !
I paid $300 for the first one, it was dead, which of course was a fried PT.
The second one was working, 500 bucks but included a JBL gray frame D120F.
Buy it! Have we steered you wrong yet???