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What is the function of a pre-amp?

Discussion in 'Amps and Cabs [BG]' started by Bassfrog, Aug 19, 2002.

  1. Bassfrog


    Jun 2, 2002
    I am playing bass for utmost 10 years, but always used combos or an end-trap. Probably this sounds stupid but I don't know what the exact purpose is fom a pre-amp. How do these things work and why is it necessary? What are the preferences?
  2. jokerjkny


    Jan 19, 2002
    NY / NJ / PHL

    the function of my Demeter pre is to make me happy whenever i play.. :D

    but seriously, a rack preamp's job to raise and push up your bass' weak signal, so it can be loud enough to drive a power amp which in turn drives your cab's speakers.

    also, it can improve your tone greatly with the use of its EQ, brite & deep switches, 12AX7 tubes for warmth, and also make your whole setup more versatile with a built in effects loop, tuner out, direct recording XLR out, master volume, mute switch, etc.
  3. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts

    Your combo amp can be separated into three sections:

    1. preamp...the part with the volume and tone controls

    2. power amp...boosts signal from the preamp enough to drive speakers

    3. speaker(s)

    What's an end-trap? :confused:
  4. BigBohn


    Sep 29, 2001
    WPB, Florida
    Well all a combo is, is a preamp, poweramp, and speaker in one cabinet box. People with big rigs just get a separate one of each [preamp, poweramp, speaker(s)] for modularity and ease of upgrade.

    The preamps purpose, as stated previously, is to just boost the low voltage signal from the bass to the poweramp, where massive amounts of electricity are applied so the speakers can move. The difference in preamps are the variety of frequency variation or signature tones you can get. The preamp is where the true tone of your rig is variable. The poweramp is the only true component that many bassists can agree on having the most minimal effect on tone.
  5. fadlan bassman

    fadlan bassman

    Oct 23, 2001
    does that mean my emg dc40s may be overpowering my ampeg b2 preamp?

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