# DIY Looper pedal help



## hollowbody (Jan 15, 2008)

Hey, I'm looking for a schematic for the following:

an A/B looper, with an additional loop, a master bypass and a tuner out. I want to be able to switch between a "clean" loop (compressor, etc.) and a "dirty" loop (OD, fuzz etc.) with one switch, so that I can turn multiple effects within those loops on and off at once, but I also want a third loop to function as an effects loop, like in an amp, where I can splash in certain effects to either the clean or dirty loop (delay, tremolo, etc). Then the master bypass and tuner out is pretty standard. 

I've seen schematics for loopers with 3 or 4 loops, etc, but haven't come across something that shows me how to switch between 2 loops with one switch, and then a 3rd loop that can be added onto the signal after the A/B loops are processed.

If anyone could help, that would be hugely appreciated!


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## Guest (Aug 26, 2008)

hollowbody said:


> I've seen schematics for loopers with 3 or 4 loops, etc, but haven't come across something that shows me how to switch between 2 loops with one switch, and then a 3rd loop that can be added onto the signal after the A/B loops are processed.


Break it down:

First you want a tuner mute. A tuner mute is a looper with no return signal. You might want to tie a the output to ground when you engage it and of course you don't need the return jack. The tie-to-ground can help if when you open it up to tune you get a lot of hum. Other than that it's the same as...

...a master bypass. A master bypass is really just a single loop. Only instead of having effects in the loop you have more loop pedals. Off it passes your signal from in to out. On it passes your signal to other loopers. So a master bypass is this:

http://www.beavisaudio.com/techpages/PedalHacker/LooperWithLED.gif

Build two, use one as a tuner mute. If you're building it all in one box instead of wiring the outs to a jack you'll wire them to the next switch in your box. Like this:

http://home.centurytel.net/flanneldrawers/3-loop-w-tuner-out.jpg

Now you want an A/B loop selector. This is what you'll place in the loop of your master bypass looper. See this:

http://www.diystompboxes.com/smfforum/index.php?topic=61424.0

If you got a 4PDT switch you could add a nice bi-colour LED in there.

Finally you want another loop after your A/B loop for additional effects. Well, that's just another looper like your master bypass looper.

Does that help?


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## hollowbody (Jan 15, 2008)

iaresee said:


> Break it down:
> 
> First you want a tuner mute. A tuner mute is a looper with no return signal. You might want to tie a the output to ground when you engage it and of course you don't need the return jack. The tie-to-ground can help if when you open it up to tune you get a lot of hum. Other than that it's the same as...
> 
> ...



Hey Ian, thanks a lot!

Just one thing. The 4PDT and dual led, what does the wiring for that look like? I have no experience with that type of switch and led (not that my experience with other types is overwhelming).


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## sysexguy (Mar 5, 2006)

You can do the 2 colour LED with one switch pole.

The led goes between ground and the common with a current limit resistor in series and the negative psu is on one leg and the positive is one the other. If you are just using a 9v supply, you can create a virtual ground just for this led function with 2 more resistors.

An easy to find (+or-) 3pdt footswitch will be fine.

In a simple loop using a dpdt, the signal enters common pole 1, out puts common pole 2 and one pair of legs is jumpered (bypass) while the other is wired to the send and return. To do the clean/dirty loop, you just need to mirror the loop legs ie. remove the jumper and wire the second loop just like the first one.

Andy


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## Guest (Aug 26, 2008)

hollowbody said:


> Hey Ian, thanks a lot!
> 
> Just one thing. The 4PDT and dual led, what does the wiring for that look like? I have no experience with that type of switch and led (not that my experience with other types is overwhelming).


A 4PDT is a DT switch with an extra pole. Small Bear carries them. Hella expensive. So you wire up the first three poles as per that A/B diagram in that thread I posted. And use the forth pole to toggle between two LEDs or to toggle the state of a bi-colour LED. Jack Orman has a blog post on bi-colour LEDs that lays it all out nicely:

http://www.muzique.com/news/bicolor-led-in-a-stompbox-again/

Honestly, I'd build all these pieces in separate boxes instead of one big long Hammond box. I know the big long boxes are sexyattactive bits of kit, but they can be tight to work in and as you can see: a tad confusing. Plus, if you build it all in separate boxes it becomes very modular. Need another loop? No problem: add it in there. Another A/B loop selector? You got it! You can use smaller boxes but start bigger if you need a little more room to work.


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