1965 Epiphone Futura EA12RVT

[Bmxbarspin724]

I have a 1965 Epiphone Futura EA12RVT, that i just got at a garage sale.

I looked in the internet for a straight week and I found that the 1964 is pretty common and the later 1966 are common too, but i am having a really hard time finding information on the 1965.

I was just wondering if anyone has any information on this amp? or if anyone here has ever owned one.

the tremolo doesn't work, and i was wondering how or if i could replace it.

I haven't checked the wiring yet, which is what I'll do before I buy any replacement parts.


thanks for the future info.


-Noah.

[capnjuan]

Hi Noah: and congratulations on your new amp. The year is important but for maintenance and repair, matching the tube lineup to a public domain schematic counts more. This is the schematic for the Epi EA12RVT http://www.schematicheaven.com/gibso...rvt-futura.pdf, year unknown. It has twin 7591s for output tubes; is that what yours has?

I've never owned one and don't have any personal knowledge of this amp but the tremolo isn't something that you take out and replace: it isn't a chip, circuit board, or modular part in any sense. One 1/2 of one tube is an oscillator that causes the sound heard to go up and down.

There are several purely mechanical things that can be bad; the button switch on the footswitch could be dirty, the input jack where the FS cable goes could be dirty or corroded, and the tube 1/2 could be bad ... but this is the least likely problem.

From the schematic linked above, the tremolo circuit:



There are three capacitors highlighted above; they are part of the trem circuit and, because the trem is electronically 'on' whether it's switched in or not, all the little pieces and parts of the circuit are working anyway. These small parts, more often than not and if the mechanical items above are okay, would need to be replaced.

If you aren't comfortable screwing around under the hood or don't have a friend who is, then you'll need to think about taking the amp somewhere to get it fixed. According to the schematic, the amp ought to pump out close to 30 watts of mid-60s power. If the reverb works and the speaker's okay, it'd be worth putting some money into. Replacing these caps and some other incidentals might be an hour or so of bench time ... not too expensive. Good luck with your amp. CJ

[Bmxbarspin724]

thank you for the information.


Yes it has a pair of 7591's, but it differs from that schematic as it has 4 6EU7 tubes, 2 12AU7 tubes and 1 OA2 tube.

[capnjuan]

Hi Noah; hmmm ... well .. I looked around, Schematic Heaven and a few other places ... no could find matching schematic. Your amp may be stuck in a 'line change' as they say in hockey. As much as anyone, Gibson/Epiphone made continuing electronic changes without leaving much documentation behind; all of the Gibson GA35RVT, GA45RVT, and GA55RVT have your same tubes but in different numbers and combinations.

In any event, the only way to fix the tremolo is to replace the little pieces and parts that do the work. I'm sure a competent tech can determine which ones belong to the trem section; it's matter of studying the amp and its circuit board. If you get it running well and if it doesn't have one, you ought to try treating it to a new speaker before you finally decide what to do with it. Depending model and TLC, these can have pretty good tone at a reasonable price. CJ

[RWood]

In addition to everything CJ just said, this:
Check or replace your 0A2 tube. That is the one doing the tremolo oscillating, and it is an odd but not entirely uncommon tube that was sometimes used in organs. Thanks to Gibson using them in so many different models all in a brief, recognizable time period, it means you can copy from a schem that may not be your exact model but it's tremolo is wired the same.

Richard

[Bmxbarspin724]

I think i will replace the OA2 tube.


I looked on an old blue book online and it said that my amp is the same as GA-30RVT made by gibson, which isn't surprising. I looked it up and the GA-30 uses the same tubes as in my amplifier, and in the same order.

From what I hear, this amp is heralded as a pretty clean amp. but even when i turn it up halfway, it still distorts and I can recognize the difference between speaker break-up and amplifier distortion, so I was wondering,

Is there anything that could be worn out that could be making my amp less clean then it should be?

The power tubes? or the preamp tubes or both?

[capnjuan]

... so I was wondering, Is there anything that could be worn out that could be making my amp less clean then it should be? The power tubes? or the preamp tubes or both?

Yes; there are things that could be worn out that mess up your sound ... and ... it could be the tubes. But unless the amp has been beaten up pretty hard or has a history of problems including shorts - others might fee differently - the tubes are likely to be the least of your problems.

There are general maintenance problems that can crud up your tone; dirty/corroded input jacks, reverb can in/out jacks, footswitch buttons, and controls. Cleaning up the amp would be time and money better spent - cheaper too - than on a new tube set. If cleaning it up doesn't do it, then chances are the problem(s) is/are electronic - worn resistors and capacitors. If it'd been sitting around waiting for a garage sale, chances are nobody's shown it any love for some time.

You can try throwing tubes at it and I hope that would do it but I'd probably bet that it wouldn't. Good luck with your amp. CJ

[Bmxbarspin724]

It was one bad tube. I just swapped them in and out with the other tubes I had that matched and it worked wonderfully.