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Best power tubes for 70's Ampeg V4?

Discussion in 'Amps and Cabs [BG]' started by Basonsubatomia, Jan 29, 2003.


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  1. Basonsubatomia

    Basonsubatomia

    Nov 8, 2002
    I am in the unfortunate position of receiving a new (early 70's) Ampeg tube amp from EBay and having to replace a tube which broke in transit. Figured I might as well retube the thing, so what tubes have you got and liked? From what I've read, I'm leaning towards a matched quad of Svetlana or Tesla/JJ 6L6-GCs.

    Any feedback is appreciated.
    -Jason
     
  2. I recently put in a quad of Sovtek 7027's. I had considered the 6L6's--look for Lord Valve's article--but instead just bit the bullet and sprung for the 7027's from Parts Express.

    Many people put in the 6550's but I was concerned about the extra filament heater current draw.
     
  3. I'd go with the JJ 6L6GC's. You could sub 6550's for more headroom. They are a plug-in replacement that is even listed on the tube charts of later V4's. 6550's will also last longer.
     
  4. Rock City

    Rock City

    Apr 8, 2001
    Boston,Ma
    I would not use 6L6 in any V-4, as I've had bad luck in the past. A 6L6 was never made to take the punishment that those amps generate electrically. I do about 50 V-4 conversions a year, and always reccomend Svetlana 6550, as they're my favorite for tone and durability. I've done a couple with the Sovtek 7027A, but they're really nothing but an over-blown 6L6, so we'll see how they last. I know there are lots of people who use 6L6 in these, but I'm not nuts about them.
    GEEK
     
  5. The 7027 was originally, even back in the day, just a way for RCA to market its 6L6GC to the hifi crowd. There are additional grid pinouts for nonstandard biasing, but the tube inside, the plate, the screen, the whole shooting match, IS a 6L6GC. Ampeg amps do not utilize the extra connections and as such, 7027s are a waste of money.
     
  6. Though the graphs for the 7027 and the 6L6 look identical, I check the specs in the old tube manuals and noticed a very slight difference in one or two capacitance values. Don't know if it's enough to affect tone (probably not) but what the heck, this set of tubes out to last another 30 years--most of the tubes were still the original Magnavoxes....so i put 7027's in there so it "looked" original.


    One day I'll drop 6550's in there.
     
  7. Basonsubatomia

    Basonsubatomia

    Nov 8, 2002
    GibsonGeek - Mine's (probably) a '72-'75, according to the Bluemuse dating info page. Any worries about the extra filliment draw with the 6550s in the (slightly) older ones?

    Thanks for all the info everybody!

    -Jason
     
  8. They all used the same power tranny. Magnavox Ampegs, which is what yours is, had a tendency (along with their TV's of the time) to have bad power trannies. Fortunately if it was going to be bad, it went bad very quick, so if yours is still working after all those years, it should be OK. If you're really worried about 6550's, just buy a separate filament tranny
     



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