Two effects, One 3PDT

[jimmy54]

Hi fellas,

I want to run two effects in one enclosure and use a single 3PDT footswitch to turn the effect on/off and use a DPDT switch to choose between the two effects (so only one is running at a given time).

Would I just take the circuit in/outs from each circuit and attach them to the outerlugs of the DPDT and then connect the in/out from the 3PDT to the centre lugs?

Like this:

Effect 1 In   ---I   I---   Effect 1 Out
3PDT In      ---I   I---   3PDT Out
Effect 2 In   ---I   I---   Effect 2 Out

Cheers

[Peter Snowberg]

That will do it all right. 

[Mark Hammer]

And that wiring can also be used to make a dual loop-selector in case a person wants to select between combinations of FX.  Simply replace the word "effect" with "loop", and tie each of those points to a jack (as opposed to circuitboard), and away you go.

[jimmy54]

Thanks fellas.  Would there be a problem with popping if the switch was used with an effect on?

[Mark Hammer]

As long as there is not a cap with a free end at the other side of the switch.  If you are concerned, you can always place a 2M2 resistor between each of the "effect in" logs and ground.

[mydementia]

I'm still struggling with my attempt at a Grace and Big Daddy in the same enclosure.  I'm using a 3PDT stomp switch to turn the effect on and off (bypass) and an 3PDT toggle to select between the Grace and Big Daddy I/O.  My stomper is set up like all the GGG projects and my toggle is set up pretty much like jimmy54 described...except I ran power supply ground to my 3rd middle lug, then a ground wire out to each effect circuit.  This isn't really isolating the circuits as I get voltage into the 'off' circuit - albiet lower voltage than when it's 'on'.  The end result is a ridiculously boosted output with flavors of Grace's overdrive and Big Daddy distortion (when either circuit is selected).  I'm also trying to share the volume pot - but this may be where I'm going wrong (since the volume pot is set up as a variable resistor with the circuit output going to one lug, and the other going to the output jack).  If I use individual volume pots and wire both outputs to the 'out' jack, do you think it will work?  How do I eliminate back-flow?

This is not an attempt at hijacking your thread .  My problem is along the same lines that you're working on, so I thought it fit!

Thanks for looking.
Mike

[jimmy54]

Mike, I had toyed with the idea of sharing the volume pots of two effects but thought it would be too much hassle.  One solution to that may be to use a double-gang pot.

[formerMember1]

don't know if this helps, or if it is what you guys are doing....
http://generalguitargadgets.com/pdf/two_in_one_wiring.pdf

with the popping, it seems that the pulldown works for the "caps", but i always have annoying popping from an LED in my wah.  I tried a 220uf electro to ground and that only makes the LED blink when turned on, it still pops. I even have grounded input wiring and it pops.  When i remove the LED it is fine.... It is a blue LED, so maybe a REd LED won't need so much current and maybe it won't pop then.... I think i have a 2.2K resistor with the LED...

[mydementia]

formerMember1 - I used that GGG layout on my uncle's TS808/EA-Trem 'blues box' - worked great!!  Since I never intend to run the Grace signal into the Big Daddy signal...I was trying to be clever with my switching (and save a precious stomp switch!). 

I'm going to try individual volume controls for each circuit with the outputs running to the 3PDT toggle...still have to make sure my bypass stomper still works...

Anyone had experience sharing pots?  Is my concern about 'backflow' valid at all?