Power tube type vs. power output

Discussion in 'Amps and Cabs' started by guitarist58, Feb 6, 2008.


  1. guitarist58

    guitarist58 Member

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    Some time back on TGP I read that you don't necessarily have to have a certain power increase when going to a "larger" tube - say from 6V6 to 6L6 or 6550. In other words a power section of an amp with 2 6L6 doesn't always equal 30 watts or 50 watts or whatever. Alas, I can't find the post or who posted it...

    My question is can someone design an amp that uses say 2 6550's and have a power output of 30 watts? or a 2 6V6 "Class AB" amp that puts out 12 watts? Would the amp still be able to be biased "warm"? Could it still have robust, good sounding transformers?

    Is what I'm getting at similar to power scaling but just something that is at a predetermined level? :confused:

    I guess why I'm wondering about these things, is that everytime I've heard amps or recordings of amps with 6550 power tubes driven to power amp distortion, I thought it sounded great! I don't play very loud, however... I'm more of a low wattage amp kinda guy I guess...
    I also usually prefer amps that are typically labeled "Class AB" (push-pull?) to amps that are ("single ended"? whatever that means :eek:)

    Any thoughts would be really appreciated :)
     
  2. Blue Strat

    Blue Strat Member

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    Yes, those things can be done (and have been done). It's easy to design an amp that doesn't produce the full potential power of whichever power tubes it uses. A weak power supply is one of the keys.
     
  3. BBQLS1

    BBQLS1 Member

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    Circuit design plays an important role in power output as does how the power is measured. Most of the time it's measured at the loudest "clean tone" the amp can produce.

    Example:

    Marshall 1987, 2 X EL34s at 50W
    Trainwreck, 2 X EL34s at 35W
     
  4. Tone_Terrific

    Tone_Terrific Member

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    To rephrase the question:

    Does a power tube's distortion and frequency response characteristics change if it is run at lower voltages?

    The power output certainly will. Is a different signal input level required to achieve full output? Should OT characteristics be rematched for voltage/power? Is the essential character altered? Is the preamp character altered to compensate for output stage response?

    !! There's a book to be written here!!
     
  5. guitarist58

    guitarist58 Member

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    Thanks for the replies, guys! I got pulled away from TGP all evening...

    I'm just pondering some of these "tone mysteries" :p I think it would be fun to have an amp with 2 6550's that I could crank and still be in the same room with without going deaf! LOL
     

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