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Let's pretend I have no idea what a preamp is...

Discussion in 'Pickups & Electronics [BG]' started by bassanddrums, Apr 29, 2009.

  1. bassanddrums


    Nov 28, 2008
    I know this is a stupid question because everyone else knows what a preamp is. But what does it do? I know it gets a signal ready to go through an amp (thanks Wikipedia) but I'm hearing stuff like standard, filter, on board or off board.

    Have forgiveness for n00b question.:bag:
  2. bassanddrums


    Nov 28, 2008
    So n00b no one will respond
  3. Jazzbassman23


    Apr 20, 2000
    On board simply means the preamp is built into your bass, while an off-board or outboard means that the preamp is housed in a stompbox or rack gear format.
  4. Preamp is an electronic device which amplifies (pre-amplifies? :) the signal before it will get to the amp. Why? - You can get better signal/noise ratio, so longer cable could be used, and clearer signal recieved (theoretically).

    Usually preamps have simple toneshaping abilities, like 2 band or 3 band equalizer, which enables you to boost/cut lows, mids and highs parts of frequency.

    There are drawback of preamps, fo-sho:
    1. If you have fairly hot pickups, you can overdrive the preamp, because each preamp has it's own headroom.
    2. Due to transistors used in preamps, the thermal noise occurs (it's hearable if you make gain on max, but not playing a bass).
    3. Also, transistors colors the signal, more or less, but there always nonlinearity distortions when signal passes through active circuitry. Usually it varies from subtle to unhearable at (and almost not noticable with oscilloscope, i believe).

    Also there are two confronting armies: active circuitry-lovers and haters ;)
  5. Im trying to figure out why my Fender J has just stopped making sound, can preamps just blow for no apparent reason? Ive checked everything I could think of but it seems "out of nowhere". I play at low volumes through a 50w practice amp, super low abuse....it just stopped playing. Its not the amp, that works fine on other basses, Im now ready to throw it up in the air, let in smack off the ground, and then hopefully it will start playing again. Ive been playing bass nearly 22 years but this is my first active/passive bass, and just learning about preamps myself. Any thoughts are greatly appreciated. Thanks.
  6. SurrenderMonkey


    Aug 18, 2006
    a drained battery is often the culprit. Many preamps have their on-off switch hooked to the input jack. So if you leave your jack in overnight, it will drain the battery.

    Pre-amps can usually be bypassed, either with a toggle switch, or by pulling the volume pot up. If you have passive pickups, then your bass will then be completely passive and should work without the preamp.

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