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Effect of # of preamp tubes on tone

Discussion in 'Amps and Cabs [BG]' started by MentalBass, May 3, 2005.

  1. Sorry to keep bombarding you all with questions, but, in the words of Chief Wiggum, "... it's the only way I'll learn." :p

    I've noticed that the Mesa M-Pulse 600 has 2 preamp tubes, while the Big Block 750 has 4, as does the Aguilar DB750, both of which are purported to sound "tubier" than the M-Pulse 600. Then there's the Ampeg SVT-6 PRO with *six* tubes in its preamp and driver sections. Is the number of tubes in the preamp/driver proportional to how close a hybrid head approximates an all-tube head's tone?

    Thanks for your input, everyone.

  2. illidian


    Jul 2, 2004
    Sometimes, but not always.

    I found that the Mesa M-Pulse sounded more "tuby" than the Ampeg hybrids.

    It's not about number of tubes, it's about how they are built into the circutry and the EQ.
  3. I dunno if its just me, but I don't really like any of Ampeg's hybrid stuff. Anyone else feel that way?
  4. Nope, the SVT-3 sounds sweet.
  5. I too am not a fan of Ampeg hybrid. A vintage SVT was the only ampeg amp I've ever heard that really really impressed me.
  6. kringle77

    kringle77 Supporting Member

    Jul 30, 2004
    Massena NY
    The Aguilar db659 has two tubes and sounds more "tubey" than many out there with more. It really is how they are put together. The hybrid ampeg stuff is pretty great sounding at home but I find that they do not cut through a band as well as the old svt-head. The hybrid stuff seems to have a certain softness to the sound that doesn't cut it live. For the money and the sound, I use an Aguilar AG500 solid state head live. It sounds really warm and tube like. But, it will cut through anything in the worst of rooms. I played an Ampeg svt4-pro for years and it was great but the aguilar works better! Just my .02
  7. metron


    Sep 12, 2003
    # of tubes generally will not make an amp sound more or less "tubey" You have to understand that the tubes drive different parts of the preamp. For example my preamp has five tubes. They are used to drive the gain, master volume, DI out, eq, and crossover. So Im not even using all of the pre tubes most of the time.

    "Tubey" sound comes from how the circuit is designed. Take two preamps that have one tube each - the Alembic F1-X and the Demeter HBP. There is a world of difference in the sound. So the moral of the story is # of preamp tubes does not make the difference. Your ears do. :D
  8. Hawkeye

    Hawkeye Canuck Amateur

    Ditto, I like the tone on my SVT3 Pro. My Peavey Max Preamp sounds almost as good when plugged into the SVT3 Pro's power amp in and it has only one tube vs. the Ampeg's 5 tubes.

    Both of these are running Electro Harmonix tubes.
  9. silky smoove

    silky smoove Supporting Member

    May 19, 2004
    Seattle, WA
    The BBE Bmax-T only has one 12AX7, and it reportedly sounds very tube-like because the signal is routed through the tube, then gets EQ'd, compressed, sonic maximized and then ran through the tube again. Or at least that's how I understood its signal path...

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