Digram or layout for switching between 2 effects in 1 pedal?

[audioguy]

I would like to build a boost pedal that has 2 different units in the same box. Just to get a different quality without building 2 boxes.
Where can I go to get a diagram (pics would be awesome too) of how to wire such a switch. Im hopinh its pretty easy, as Im really new to this.. but damn its fun.

Anyway... thanks guys!

Audioguy

[Mark Hammer]

So if I'm reading you right, you want to be able to switch from boost  *circuit* A to boost *circuit* B?  Or do you simply want to switch from boost *level* A to boost *level* B?

The second one can be as simple as using a SPST switch to connect another resistor in parallel and change a circuit's gain.  

The first one is analogous to wiring up a "loop selector", which in itself is about as easy as wiring up a normal DPDT true-bypass switch on a stompbox.

Stated simply (and my pardon if too simply), a DPDT stompswitch has two "commons" - contacts which are always in contact with *something*.  When you wire up one of these babies for bypassing an effect, those commons go to the input and output jacks.  Each time you step on the switch, the commons change over to the set of contacts opposite to where they are connected right now.  

If you wire up one of those sets of contacts directly to each other, then when the commons switch over to that set, the commons are essentially in "straight wire" contact with each other, such that the input and output jacks are separated only by the wire linking them to the switch and switch lugs.  If you wire up the other set of contacts to the input and output leads from the effect circuit, whenever the stompswitch changes over to THAT set of contacts, instead of a straight wire between the two commons, there is now this entire circuit.  Voila, bypass switching.

So how about if the little bit of straight wire linking the one set of contacts is removed, and instead, those contacts go to the input and output leads of a second effect?  Voila, instead effect "swapping",  The switch will now select between effect A or effect B.

You will note however, that the input and output jacks (and the commons they are hardwired to) are ALWAYS in contact with the input/output leads from one of the effect circuits, with no ability to cancel the effect.  For that, you need a second stompswitch.

This switch is wired up exactly like our effect bypass switch described at the beginning.  One set of lugs is hardwired together, one set is for going to and from the effect circuit, and the commons go to the input and output jacks.  But wait a minute.  Don't the commons on the other switch already go there?  Not any more they don't.  NOW they go to that set of contacts which would normally be connected to an effect circuit.

So, to (hopefully) unconfuse, one switch is for effect/no-effect.  If you select no-effect, everything in the box is bypassed.  If you select effect, then the second switch will select between A or B.

Certainly one thing to keep on top of here, especially for beginners, are inputs and outputs.  I recommend using a distinctive colour hookup wire for inputs and outputs.  Personally I like to use white for in, and blue for out (clean to bluesier, get it?) but you can use whatyou want as long as it helps you to reliably connect things that need to be connected and keep things apart that need to be apart.

You can use a 3PDT with a third common and set of contacts, for connecting indicator LEDs.  I will draw attention to the fact that LEDs require current, as do each of the effect circuits.  Remember, they are still connected to the power supply even if they aren't connected to your instrument.  Between the various LEDs on board and a pair of circuits, that may well be too much to let a single 9v battery last very long (although many booster circuits can be low current ), so you may end up having to wire up a jack for a wallwart supply.

As a beginner at this, my advice would be to skip the LEDs and the 3PDT switches for now (although you can certainly buy one and leave the LED wiring of the 3rd set of contacts until a later point), so that you can at least try running your booster pair on one battery.  That'll also mean less machining and risk of screwups.

[audioguy]

So, to (hopefully) unconfuse, one switch is for effect/no-effect. If you select no-effect, everything in the box is bypassed. If you select effect, then the second switch will select between A or B.

Thanks for your reply!

This is exactly what Im looking to do. Have a foot switch for ON/OFF and maybe a slider of toggle to select one circuit or the other.
Im going to have to read and reread your reply a few times to get my brain around it, but I think I follow you.
Do you know of any sites with a diagram of the configuration?


Audioguy

[Gringo]

A good example of what you want to do is RunOffGroove's DoubleD:

http://www.runoffgroove.com/doubled.html

Good Luck!

[audioguy]

thanks!