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

[mailing gigaspeeds]

Still fiddling with the guitar effect ;-)
I was wondering what the difference was between a synth signal and a 
guitar signal.

I found this about guitar pickups  :
The output voltage of pickups varies between 100 mV rms to over 1 V rms 
for some of the higher output types.

I want to save the trouble on calculating and measuring stuff out :p , 
surely somebody must have done it before on synths .
Anyone can enlight me on the output voltage rms of a synth (output VCA)?

thx
Benjamin


Derek Holzer wrote:
> 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.
>