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6v6 in place of El34s?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by ccoker, Feb 21, 2006.

  1. ccoker

    ccoker Supporting Member

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    can you sub 6V6s for El34s?

    Rivera R30 head
    bias would have to be adjusted..

    just curious to try if possible

    the 30w EL34 with a 2x12 Germino oversized cab is still damned loud...
     
  2. Blue Strat

    Blue Strat Member

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    If the plate voltage is higher than 440V this sub is seriously questionable. Might work, might blow up the 6V6s.
     
  3. wsaraceni

    wsaraceni Member

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    i was going to ask the same question. eurotubes states that you can run a dual rec in el34 mode/tube rectified with their 6v6s and new rectifiers. a friend wants to try it out.
     
  4. goneracin

    goneracin Member

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    You also have to change the impedance selector to account for the 8k load vs 3.4 k.
    Like was stated, as long as you arent running a high plate voltage, it works pretty well.
     
  5. Swarty

    Swarty Member

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    I've been doing this in '70s Marshalls for years, I actually got the idea from Ken Fischer who advertised his Express as being able to use either tube... then I discovered that they have almost identical bias voltage requirements. Ideally (for optimum throughput) you would lower the head impedence to be half that of the cab when running 6V6s.
     
  6. wsaraceni

    wsaraceni Member

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    would that work the other way around? el34s in a 6v6 amp like a deluxe or something
     
  7. donnyjaguar

    donnyjaguar Member

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    I think the filament current is very different on these 2 tubes.
    1.5A (EL34) vs 0.45A (6V6). For a pair of tubes the difference is more than 2A. This would probably overtax your filament winding and either burn it out or cause the voltage to sag badly, which would impact (negatively) all of your tubes.

    DJ
     
  8. sampleinajar

    sampleinajar Member

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    Supposedly the new JJ 6v6 tubes can handle higher plate voltages. Up to 480 (??) Anyone have experience with these tubes at high voltage?

    Cheers,

    Steve
     
  9. wsaraceni

    wsaraceni Member

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    so is the moral to ...A) not switch tubes or B) only do so if you know what is going on and can test properly.

    i guess what confuses me is if you trust someone like eurotubes to say its ok to use jj 6v6s in a dual rec.

    also if you were to do so, what would the wattage difference be?
     
  10. Swarty

    Swarty Member

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    Although the wattage may be cut in half the volume certainly will not be. An output transformer may act as a bottleneck and saturate w/ EL34s, but with 6V6s it will deliver the max that the 6V6 can throw at it. So, depending on the output transformer the 6V6s may actually sound cleaner than EL34s.
     
  11. Red Planet

    Red Planet Member

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    I believe the JJ 6V6's will take 500 Plate Volts. I know they will take 490 because I put a set in my 100 watt Marshall Superlead. Oddly enuff not a lot of loudness difference. A much lower clean headroom but thats about it.
     
  12. Matt H

    Matt H Guest

    "A much lower clean headroom but thats about it."


    exactly! I dropped some 6v6's (and a 12ax7 instead of 12at7 in the PI) in a bassman 50, and it went from "ridiculously clean and loud" to "dirty galore and still freaking loud".
     
  13. VintageJon

    VintageJon Member

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    6V6 in an EL34 design? Ya'll are scaring me! 400V vs. 2000V Max plate voltage just seems too great a difference.

    No IPD posted in any of the above posts... Ya'll are scaring me. I reackon someone will spend a lot of money fixing this mistake before long...
    (Perhaps they'll spend it with me. Ya'll feel free to invent your own specs/rules/methods. I'm waiting to put it back together for you.)

    -Jon
     
  14. Swarty

    Swarty Member

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    Lots of '70s Marshalls have plate voltages less than 400V and thus are perfectly suited for 6V6s, better so than a Deluxe Reverb in that respect. As I mentioned above, I did not discover this on my own, I made the connection in an old advertisement for the Trainwreck Express in Vintage Guitar in the mid '90s. The advertisement touted it as being able to run either tube with no adjustment. I popped a pair in my '71 Marshall (about 380V) and low and behold, they worked just fine. I currently own 3 '70s 50w Marshalls from '71-'78 and all are between 380V and 410V. Would I run a pair of 6V6s at 450V, heck no... I don't care if they do tout them as going to 500V, they're not going in any of mine or my customer's amps. But, at Deluxe Reverb voltages, why not give it a try?
     
  15. Shea

    Shea Member

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    Yup, my master volume JMP has a B+ of about 390 volts. I'm thinking of putting in a pair of 6V6s to drop the volume by a few dBs, so I can turn up the master volume higher.

    Shea
     

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