bypassing a section in a guitar synth voice

[o_gold]

Hello,

I build a 9v synth voice pedal that is the following :

556 timer as an oscillator (stepped tone generator) ---> into a lp filter---> into an overdrive---> into output jack

I would like to add a section of a tremolo after the overdrive section and before the output jack, but I would like to have the option to bypass the tremolo section and to go out to the outputjack from the overdrive.

what are my option to do bypass of a section ?

so if to make it more clear (I hope), I would like to have the option to choose with a single switch between:

state 1: 556 timer ---> filter ---> overdrive ---> out
state 2: 556 timer ---> filter ---> overdrive ---> tremolo ----> out

Thanks for any help!

[patrick398]

Standard dpdt toggle or foot switch set up would work. I can't draw it at the moment but if you look at dpdt bypass wiring you should be able to work it out

[patrick398]

This is how I'd do it

[o_gold]

Standard dpdt toggle or foot switch set up would work. I can't draw it at the moment but if you look at dpdt bypass wiring you should be able to work it out

Thanks! will look it out.
I also was thinking perhaps will be better adding a blend pot instead of a switch . will it be more complicated? possible to make a passive blend using just a knob ?

[patrick398]

You could try, it might work ok if you split the signal coming out of the overdrive, one line goes into one side of a high value pot, the other line goes to the tremolo, out of the tremolo into the other side of the pot. Take your output from the wiper. Not sure how much separation you'll get and could cause other unwanted effects.

[o_gold]

This is how I'd do it

Working great! apart of the obvious 'tick' when switching between position but I guess this is unavoidable.

Thanks

[patrick398]

Do you have dc blocking cap on the outputs of the distortion and the tremolo? And are there pull down resistors?

[o_gold]

Do you have dc blocking cap on the outputs of the distortion and the tremolo? And are there pull down resistors?

I do have dc blocking cap both on the distortion and tremolo but got no pull down resistor on the output of the distortion

[patrick398]

Try a 100k resistor to ground after the output cap. If that cap is leaking a small amount of dc onto your output that could account for switch noise. The resistor will bleed unwanted DC to ground.

[PRR]

If the tremolo has a proper Depth control, and is clean, you can just turn the Trem to zero.