[sdiy] Output level on DIY distorion effect super duper low.. why?

[harrybissell]

Hi Johnathan

Its an odd circuit you have there.  The 1N4733 looks like it will
always be forward biased with a .7V drop. No problem, but a regular
silicon would do as well.

Is the 1N91 a germanuim diode ???

I think your topology is basically wrong.  You have the diodes in the
position where they might go if you were using an opamp and not
a transistor.

I would just bias the transistor with a resistor (where the diodes are) or
with two resistors, one to 5V and one to ground. The 220pF cap might
be a little small in that case.

I'd try lowering the 400K collector resistor in value (as low as you can
stand
and still get some gain there).  Add a series resistor AND capacitor from
the collector, then run the diodes from there to ground and take the output

from there.  The capacitor will block the DC level from the collector, the
resistor will stop the diodes from loading the collector too much and
killing
all the gain.

I think your lack of gain is because the diodes (where you have them) are
basically turning the transistor on really hard... ie the input signal
can't
do much fighting the diodes. Putting them on the other side of the
transistor
(not fed back to the base) should help.

Keep up the experiments !!!  Maybe you get the synth-diy daily award for
actually building SOMETHING and posting on list :^P

H^) harry

Jonathan Arkell wrote:

> So I prototyped my own distortion effect lat night (first time actually
> doing something myself, instead of following a kit) and it works, it
> actually distorts the sound, and quite nicely I think.
>
> The problem is, that the output level is SOOOO low, but I can't really
> figure out why.  If anyone is willing to have a peek at the schematic,
> and make a few suggestions, that would be hella cool.
>
> Direct link to my schematic:
> http://blog.jonnay.net/uploads/Code/Distortion.png
>
> Excuse the roughness, it was my first time using Dia.
>
> Thanks!
>
> --
>
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