[sdiy] Volume control help

[Mikael Mørup]

Citat Scott Gravenhorst <music.maker at gte.net>:

> One thing to try is to replace the one meg resistor (R14)
> with a one meg pot used as a voltage divider.  That way,
> all
> of the expected impedances are what the circuit expects.
>
> Mikael =?iso-8859-1?b?TfhydXA=?= <Mikael at mikmo.dk> wrote:
> >Hi list.
> >
> >I'm building a small mixer for mixing audio signals in
> the
> >modular synth i'm building. The mixer i build does not
> have
> >a master volume control, so i figured it could not be
> too
> >difficult to ad one but....
> >
> >The schematics for the mixer is here :
> >
> >http://www.generalguitargadgets.com/diagrams/mixer_sc.gif
> >
> >Rather standard as far as i can tell.
> >
> >What i tried was to just put a 10k pot wired as a
> voltage
> >divider between output and ground, so that i had output
> >from the mixer one side lug on the pot, ground to the
> other
> >and my output jack to the center lug.
> >
> >What i achieved was a very very low output level, i had
> to
> >use the mic input on the main mixer to hear anything.
> >
> >If i bypass my futile attempt on the master volume
> control,
> >the mixer works fine. What have i done wrong, and how
> could
> >i implement a master volume control on the mixer ?
> >
> >Thanks
> >
> >Mikael
> >
>

Thanks

The 1M pot solved the problem.

Impedance is one of those subjects that i still have to
learn a lot more about.

Mikael