Post Amp- Pre Amps

From: Shaun.Hendricks@bergenbrunswig.com
Date: Fri Oct 02 1998 - 17:38:45 EDT


>Date: Fri, 02 Oct 1998 11:59:00 PDT
>From: Geoffrey Hackbart <ghack2@hotmail.com>
>Subject: Re: DML: CD\Cass\Radio combo have pre-amp outputs?

>Nope it doesn't.

>Later,
>Geoffrey

   Figure out your maximum watts out, get a 4 ohm dummy load that can handle
those amps. Connect a parallel high value load (I'd use a variable resistor:
but must have a min ohm value of greater than the dummy load) resistor also.
Take the tap out of the parallel resistor and hook it to whatever device you
need the pre-amp outs for. Your main power will dump into the dummy load and
the high value resistor will "monitor" the output at a much decreased level so
that you can use it as a "Pre-Amp". Diagram as follows:

IN (+)
-----+-----+
     | |
  [4 ohm] [~10ohm - 20K ohm]
  [dummy] +---------- Pre-Out (+)
  [load] [Variable Resistor]
     | |
-----+-----+---------- Pre-Out (-)
IN (-)

   The dummy load will get VERY hot at high power settings. It's better to
set your max pre amp aat a lower than max power level with the variable
resistor, and then control the volume as usual from the source. I make no
guarantees that this won't absolutely waste some high-end or cheap system. I
do know that it works for low to medium power applications. (1-20 watts) Use
at your own risk! ^_^

Shaun H.



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