[sdiy] guitar effects (small stone Electro Harmonix) vs synthesizers

[Derek Holzer]

Howdy,

mailing gigaspeeds wrote:

> Lately I bought the most recent version of the Small Stone electro 
> Harmonix.
> It's intended as a guitar effect and I notice a drop in volume/amplitude 
> when connecting my synthesizers to it. Can that be solved ?

There's a difference between the levels of voltage used (1V peak to peak 
vs 5V peak to peak, for example), as well as the input impedance. Not 
only will you lose gain, you will also lose quite a big of dynamic range 
going through a guitar effect.

As an example of how to deal with this, you can find directions for an 
adapter circuit which cuts levels to the pedal, and then boosts them 
coming back into the synth, here:

http://www.cgs.synth.net/modules/cgs60_sba.html

That said, I run synths through distortion pedals constantly (using the 
FX send of my mixer), and normally it makes them sound louder...as it 
should be ;-) But using the send/receive busses works nicely because you 
can adjust the output and input gain to taste.

> What irritates me the most (and makes it totally useless for live 
> performance) is that when I hit the enable button (footswitch) I get 
> this spike in my speakers that nearly causes  my eadrums to pop :-p.
> Is there a way to buffer that spike so I don't hear it when I enable the 
> effect ?

I would check inside and see if the DC voltage for the LED isn't 
accidentally connected to the output as well. That might certainly make 
a pretty big thump!

But any time you have a sudden onset of DC voltage (for example you 
click the pedal on while your synth signal has some DC offset in it), 
that could account for some nasty pops. So using a mixer might also 
buffer this a bit, or at least filter out the offset voltage. I've never 
connected a synth directly to a PA or amp without one.

Last but not least, here are some directions for an electronic "true 
bypass" that I ended up incorporating into one modular setup for use 
with guitar pedals (and other things) a while ago:

http://members.shaw.ca/roma/switching.html

+ bonus one which I didn't use:

http://www.geofex.com/Article_Folders/cd4053/cd4053.htm

Best!
Derek



best,
D.

-- 
::: derek holzer ::: http://blog.myspace.com/macumbista ::: 
http://www.vimeo.com/macumbista :::
---Oblique Strategy # 193:
[blank card]