Changing EL84 amp to 6V6 or ?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by dazco, Mar 17, 2004.


  1. dazco

    dazco Member

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    I have a Peavey Bravo, a 2xEL84 amp that claims 25 watts. But it's just not very loud at all. i like the tone it has before the power section really begins to get nasty, which is about 1/2 way on the master. So i was wondering what other tubes i could mod it to use that would make a considerable difference in volume and what things i need to consider.

    The current plate voltage is 388. (seems high for El84's doesn't it?) I'd really like to be able to leave the PS as is if possible, tho i realize thats probably not gonna happen. I was thinking about making some adapters instead of re-wiring the sockets because the sockets are circuit board mounted and different sockets would be torture to impliment. But the important things i need to know is what i need to know such as what tube would work and get a good volume boost with the least amount of work, how to determine if the PS has enough current, what plate voltage i need for the new type, etc. In fact, if someone can just give me a rundown of everything i need to consider and whether there even IS a tube type i'd be able to impliment that would get me a considerable volume boost.

    And yes, i have considered speakers and am considering a 103db Eminence Red Fang. But i don't think that will get me there alone.
     
  2. Wing

    Wing Member

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    If that thing is PC board mounted, you're pretty much out of luck trying to use another type of tube. You may have to rip everything out and go PTP. Another thing you may want to try is to use Sovtek EL84Ms, if that's not what's in the amp right now. I hear they are beefier than regular EL84s. Perhaps E84Ls as well. Then you can play with the bias and screen voltage to get more headroom. 25 watts is nothing to sneeze at. I bet if you put that thing into a 4x12, it would blow the house down. You would be surprised how much difference a speaker upgrade can make. The speaker that came in my Peavey were probably the cheapest thing they could get and sounded nasty and soft compared to the Blue Dog.
     
  3. dazco

    dazco Member

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    Could you tell me what kind of peavey you're talking about and how much extra volume you got with the blue dog?
     
  4. Wing

    Wing Member

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    It was a Peavey Envoy 110 with a 10 inch speaker. Even taking account of the size difference the difference in dynamics and quality of tone was quite evident. I should clarify that the Blue Dog was in another 1x12 combo. I'm going to be upgrading that 10 inch in the Peavey to something like maybe a Blue Pup.
     
  5. John Phillips

    John Phillips Member

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    I think it might. At 103dB, that's equivalent to doubling the amp's power even over a 100dB speaker, and I doubt very much that the original is even that. If the stock speaker is only 97dB, the Red Fang will give as much extra volume as quadrupling the power of the amp! You can't even begin to get close to that with a tube change, even if it was practical.
     
  6. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    I have yet to see a db rating that is consistent between Eminence and Celestion. Dr. Decibel at Celestion says that the Alnico Blue is 100db. They say the Century is 121db, but in reality it's like 102db. Now the Eminence Red Fang is 103db?

    Seriously, you'd have to have all these speakers in one room, same cab, same amp, same guitar to really know if it was going to "get you there" over another speaker rated at XXX db.

    That said, IF the ratings were identical (pretty doubtful in my experience), the 103db Red Fang should be twice as loud as a 100db Alnico Blue. And when the speaker is more efficient, the volume is increased.

    However, the Celestion Century is "too clean and bright" from the ones I tested, so I'd imagine that the Red Fang may be similar. It will depend on how the speaker reacts with the amp, that's for sure.

    Let us know what you get and post a review.
     

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