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Vintage Ampeg Question

Discussion in 'Glowing Bottle Tube Amp Forum' started by -Hawk-, Sep 12, 2017.

  1. -Hawk-

    -Hawk- Friend of Leo's

    Oct 14, 2015
    IL, USA
    Hey all - just trying to do my research before buying something and wondered if anybody had advice.

    Amp in question is an Ampeg GS-12R (Reverberocket), supposedly a 1966, which seems to be a reasonable guess. The price is well below average from what I'm seeing. I will be seeing it in person, but want to be versed enough to evaluate it. Seller seems to be a decent person and has responded to every question I asked to the best of his ability.

    Handle is broke, but can be replaced. Tolex has some damage, but nothing extreme. Looks kind of dirty in some pics. See pics below, but seems the chassis isn't seated correctly?The seller provided two videos for me.

    -One is him cycling through all the controls while playing. No scratchy pots. Trem and reverb seem to work. Sounds fine, but hard to tell much from a phone video.

    -One shows the back of the amp and tubes.

    Here's what I know:

    -Seller bought in 1981.
    -Didn't play it for a few years at one point.
    -Took it out of storage a year ago and it squealed when he turned it on.
    -He took it for service from a tech that I am familiar with and it was repaired and given a clean bill of health. No other details on service.
    - Tubes are 7591a, 12Ax7, 6U10. He says they are original to at least when he purchased it.
    -It has a 3 prong cord.
    -Reverb makes a hum when amp is idle.

    Assuming it sounds fine, any red flags pop up? Anything I should specifically look for? I'm probably most concerned about the potential for dumping lots of money into the amp. If there was a squeal and it was repaired, what might that indicate? Should I still take it to a tech? It would probably be the same guy that saw it last year. What about the death cap? Can I assume it was taken out when the 3-prong cord was installed?

    I would plan to gig this if I bought it and want to make sure it's capable of that. I'd likely put a Cannabis Rex i have in there because I've read it's a good match and the stock speaker is supposedly underpowered.

    On a side note, anybody with input on their experiences with the amp are free to share!






  2. slider313

    slider313 Tele-Afflicted

    Jan 6, 2011
    The squealing could have been a simple pre-amp tube issue. These amps usually need $150-$200 worth of service. The power supply cap can should be replaced (it looks original in the photo) as should any other electrolytic cap in the amp. The reverb hum could be a bad section in the 6U10 or a leaking/bad cap in the circuit. The chassis is mounted with rubber shock mounts, which deteriorate over time. That's probably why the chassis isn't "sitting even".

  3. -Hawk-

    -Hawk- Friend of Leo's

    Oct 14, 2015
    IL, USA
    Thanks, slider313. I'd hoped that the caps were already replaced since it went in for service recently, but it sounds like that may not be the case.

    Still not a dealbreaker I guess, but makes me wish I knew how to do the work myself. Techs here are usually pretty slow.

  4. pdcorlis

    pdcorlis Tele-Meister

    I would think a trip to the amp doctor would be mandatory for any amp of this era - regardless of claims by the seller. I hope it's a keeper!

  5. slider313

    slider313 Tele-Afflicted

    Jan 6, 2011
    I would call the tech and ask exactly what was done. He may have just replaced a tube and installed a three prong cord. Explain you are considering purchasing the amp as a gig amp and need it to be dependable.

  6. -Hawk-

    -Hawk- Friend of Leo's

    Oct 14, 2015
    IL, USA
    Yea that's what I was thinking. Figure it's unique enough he may remember it.
    slider313 likes this.

  7. Mike Simpson

    Mike Simpson Doctor of Teleocity

    Mar 19, 2006
    Gilbert, AZ (PHX)
    I am pretty sure the amp chassis is mounted on some rubber mounts and they may have shifted. It is normal for the chassis to wiggle a little on the rubber mounts. Gonna need a special screwdriver bit...

    I have one like it.
    The previous owner replaced the handle with one of the later indestructible kind and mine has the transition knobs like they used after the stopped using blue diamond tolex and switched to black tolex.

    Last edited: Sep 12, 2017
    -Hawk- and teletimetx like this.

  8. Bob M

    Bob M Tele-Afflicted Silver Supporter

    May 11, 2011
    North of Boston
    I've got a'65. Same tube compliment. The chassis in mine is kind of wedged in there and is a bear to get out. I replaced the original tubes with new Tung Sols but the 6U10 tube is a tough one to find. They drive the reverb and will make noise. I ended up buying 4 or 5 of them and use the one that makes the least amount of noise. It's a great amp. Certainly close to Deluxe Reverb territory. 18 watts through a 12" speaker (Legend). When buying old tube amps, unless it comes with an invoice for recent work you are always well served by taking it to a tech. It's part of the package. Once in good internal shape these amps last forever.

    jimytheassassin and -Hawk- like this.

  9. teletimetx

    teletimetx Poster Extraordinaire Gold Supporter

    Jul 25, 2011
    Houston, TX
    I don't have any experience with the Reverberocket, but I do have a Gemini II from 1967 and based on conversations and other reading, there was one physical thing that was common, just in how the chassis is screwed into the amp. Here's a photo of the chassis of the Gemini II. Not a great photo, but enough to illustrate what I'm trying to pass along.

    circuit board - ampeg gII ccv2.jpg

    the metal ledge under my first row of knuckles, with the holes is how the chassis is fastened to the amp. At least in the Gemini, and most likely in the reverberocket as well, the screws used are drilled at an angle to the plywood shelf that the chassis is attached to. I figured my amp was put together on a Friday as the screw that held the chassis under the heavy transformer mostly missed the shelf (wrong angle of attack with the drill), but caught the shelf close enough for inspection.

    But not for shipping. When it arrived, the chassis had torn loose from the shelf - but only at the heavy end (where the power transformer is), so in effect the chassis was dangling by a screw, and the bump that must have happened when the chassis tore loose also busted the gasket fitting for the large can cap. All these things got repaired - which is why the photo got taken - but I happened to be reading about another Gemini II and the same thing happened in shipping for that amp as well. At some period, one of the guys drilling holes to fit the chassis in was not aiming so good. Based entirely on one actual incident and one reported. Not complete data, but worth at least thinking about.

    I have no idea if this is likely or not for the Reverberocket, but just a caution to pass along if the amp is being shipped. Make sure the chassis is adequately supported on the inside. Or pick it up yourself.
    -Hawk- likes this.

  10. -Hawk-

    -Hawk- Friend of Leo's

    Oct 14, 2015
    IL, USA
    Very interesting stuff, all. Thanks everyone for the input! This is close enough that I'd drive over to pick it up, were I to go for it.

  11. BobbyZ

    BobbyZ Doctor of Teleocity

    Jan 12, 2011
    Snellman MN
    The squealing might be a bad connection in the reverb. Had an older RR do that when you engaged reverb with the footswitch, just a bad connection on the tank, RCA connection not making good ground contact.
    That one was super loud and settings didn't change it as I recall.
    I did a Rocket non reverb that looked like this, about a 1965. That one was a very early printed board, not a bad thing but trickier to service than the older tag boards or the V series PCBs, also not as robust as either.
    If that's what this one has look for solder joint breaks where the pots connect and to do things on the board right it has to come out. All electrolytics on the board need to be changed for sure.
    Like the other guys said that "clean bill-O-health" doesn't mean a thing. So an evaluation is needed. One thing you can see right away is the cap can if it's original it shouldn't be.
    Pretty easy on those chassis to put a speaker jack in while it's at the tech's too. If that's something you'd use.

  12. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

    Mar 2, 2003
    Lawndale CA
    Yes, as BobbyZ noted the electrolytic capacitors are ancient. It really should not be used until they're replaced - that's standard service for any amp over 15-20 years old. I would also question the use of a tech that left them in. That's careless work IMO. The amp could sound fine, a cap can fail without warning and you possibly lose the power transformer and several hundred additional dollars in vintage value.

    Find a new tech. Then plan on budgeting between $150-300 on top of the amp price for simple, normal service. It'd be on the upper end - probably - if it needs tubes. Find a tech that really knows Ampegs, because most don't and often don't have good tubes on hand to even do swaps for sound testing purposes (tube testers are useless for "sound" purposes - they hit the tubes with WAY too low plate voltage)

    The same is true of any vintage tube amp. Service is like changing oil or tires on a car - has to be done. Filter and bias caps have a service life of roughly 15 years and should be replaced somewhere around that interval. A 1966 Ampeg should actually be on the THIRD set - the originals plus it should have been serviced twice. You'd be taking a chance not doing it.

    BTW I have seen all sorts of weird chassis alignments on Ampegs - they used some rather odd connections on quite a few. Just a quirk - and they are quirky amps in more than that way!
    Last edited: Sep 14, 2017
    BobbyZ and -Hawk- like this.

  13. -Hawk-

    -Hawk- Friend of Leo's

    Oct 14, 2015
    IL, USA
    Thanks for thoughts. I think they've probably discouraged me from buying it, but that's not a bad thing. Reality, another $200-300 and the suggestion to find a tech that has ampeg experience takes away some of the initial attraction, much of which was that the amp is listed at $400.

    I'm also wondering about the tech in question if he let the amp go with a "clean bill of health". Problem is, he's always been the most recommended guy in town. Go figure.
    BobbyZ likes this.

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