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connecting two outputs to one.. ?

Discussion in 'Amps and Cabs [BG]' started by The_Bass, Aug 28, 2004.

  1. Hi all... I haven't posted in a while, but I come back now with a question.

    I needed to shorten the power cord on my amp(70w combo), so I removed the head and it works now without being a fire-hazard :eek:

    but since I had it open, I decided to look around so here's my question:

    if I connect another output to where the speaker is plugged in, would I lose any sound quality or risk anything? I know that I could blow something up if I connect the amp to something that can't handle the 70watts it gives out, but if I connect, for example, a 1/4" plug to it, so I can use it as a preamp for recording and keep it at low volume, would it be ok?

    or would I lose power that it gives to the speaker, or risk blowing up the other thing connected to it?

    I hope this made some sense... thank you for your attention(and hopefully your replies too)


    {edit} oh, and another thing... might it be a bad idea to use a regular amp as a preamp?
  2. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    If you want a low level output, like line level, then you'll have to connect a voltage divider between the speaker and the extra jack. This is just two resistors, or a resistor and a pot. Here's an example.

    Connect a 2.2k and 220 ohm resistor in series. Connect the loose ends "across" the speaker. Connect the ground on the extension jack to the ground wire on the speaker. Connect the hot terminal on the extension jack to the midpoint of the two resistors. Voila.

    In practice, you'll have to play with the value of the resistors to get the right level that you're looking for. Or, you can replace the bottom resistor with a 250 ohm pot. In that case, connect the two outer terminals of the pot to where the resistor would ordinarily go, and connect the hot terminal of the extension jack to the middle terminal on the pot.
  3. thanks for your reply.

    I want the extra output I get to be amplified, at least to some extent.

    I asked google and learned a thing or two about resistors, at least enough that I think I could manage to use them. But where would I go about buying one? should the local electrician have them? oh, and does the tolerance of the resistor matter?

    could you explain for me why I should have a 2200 and a 220 ohm resistors? why not just have a 2400ohm one?

    this all is a bit confusing, but I'm learning! :confused:

    thanks again for your help!