Discussion in 'Amps and Cabs [BG]' started by Hootz, Jan 16, 2002.

  1. Hootz


    Jul 1, 2001
    Hull, England
    Call me a spakker if you must, but I ain't quite sure what the deal is with preamps. I have heard that I have one in my guitar from a knowledgable source (my tutor), and that I should play through the active input on my amp. But I still don't know what they do or anything.Could someone please enlighten me? Will playing through the passive input damage my guitar or amp, and if not what difference does it make?

  2. If you are talking about a bass (not guitar), and if you have active electronics in your bass (like your tutor said), then you should plug into the input that says ACTIVE or -10 Db or something like that. If you only have one input on your amp, then there might be a button that says PAD or -10Db or something like that.

    You should use those because the signal from an active bass is much higher than a passive bass, and you don't want to over load your preamp. Hope I helped.
  3. A preamp can mean a number of things. Consider your amp for a minute (head, combo or whatever). There are some tone and volume controls on it, I guess. There'll be some inputs on the front and probably some and outputs on the back.

    That section of the amp is called the preamplifier - or preamp for short. You might define it as the section of circuitry between the bass and the power amplifier stage and it handles tone shaping and volume controls, etc. You could consider it as begining with the input jack and finishing with the master volume control.

    On-board guitar / bass preamps (sometimes called just, "actives") do roughly the same job as the preamp just described. However, it will bring you greater tone shaping capabilities than passive tone shaping circuits. More importantly, perhaps, that capability is now directly at your fingertips rather than it being some feet away at the rig: obvious advantages.

    Preamps have what's called, "gain", or amplification. Thus, they can deliver more signal out than non-active basses. The acive input on your amp is usually arranged to cut the signal fed to it, by half, to avoid early overload of the various signal paths through the rig's preamp and, therefore, to the speakers via the power amp.

    Damage to the bass by using the non-active input on the rig is not an issue. Damage to the rig might be an issue if you're playing through the non-active input with everything turned well up. But, well before then, you'll hear the gross distortion that comes as a consiquence. In other words you'll have turned down because it sounded dreadful.... :D

    Hope that helps.

  4. Hootz


    Jul 1, 2001
    Hull, England
    Cheers you two. I appreciate it. I am yet wiser in the ways of the bassist, and for that I thank you.