Two channel looper with an added boost?

[aBunchOfPedals]

Hello,

I'd like to build a two channel looper and add a SHO clone on the return of the loop.  I've got a pedal that gets really quiet, depending on the settings and I would like to boost the volume a little bit.  I could build a single looper too, that's no big deal.  Whatever would be easier.  Can someone help me out here?  I have the SHO built and it works fine, I'm just not sure how to implement it.  Thanks!

[blackieNYC]

I've done one. I recommend this mixer
http://www.generalguitargadgets.com/pdf/ggg_mixer_sc.pdf
And this splitter, or an op amp version if you want to incorporate a polarity reverser.
http://www.muzique.com/lab/splitter.htm
Also see the polarity reverser at Geofex. My splitter incorporates this on the send side. See the switches on the three op amps in drawing 1 of 2. 2of2 is good (hit next)as well but I gave it too many bells and whistles.
http://www.aronnelson.com/gallery/main.php/v/diyuser/blackies+pedals/photo1of2.gif.html

[aBunchOfPedals]

That seems like an awful lot of work for what I'm trying to accomplish...

[blackieNYC]

Yes it is. Sorry about that.
How about an op amp buffer, followed by a series cap, then two or three 1k resistors branching out from that point.  And lastly, a 100K resistor to ground at each output. as simple as you can get and no loss.  One op amp can drive a few loads perfectly fine.Here is the runoff groove splitter blender, which may also be more than you need.  See where the RED send is? That single op amp circuit right there, followed by the stuff I just listed.http://www.runoffgroove.com/splitter-blend.html
As for the mixer, you can't get much simpler than the mini mixer linked above.  A passive resistor might work for you. 2 or 3 10k resistors that meet together at one spot followed by a 100K to ground and that's it. Or add 100k pots before the 10Ks for individual channel control. Sometimes this is fine. Heck, try a passive splitter - just 2 or 3 1k resistors branching out to each send. That might be fine if it follows another pedal(most of them) or buffer.  Straight off the guitar? Eh.No.
As for the mini mixer, you could drop the 10k pots for fixed 10k resistors if everything you would blend already has an output volume control.
You could drop that last op amp stage: see pin 3 to the two 100k resistors?  you need that, just forget the pin 5 connection. On pin 1, the output of the op amp, put a 1k series resistor (not shown), then (as shown at the output) put a 2.2uf cap in series, then a 1M to ground. One dual op amp will do the whole splitter/mixer.
As for the polarity reverser, you can skip it but just be mindful that someday you will mix two pedals and hear the low end drop as you add in the A pedal to the B pedal.  That's phase cancellation due to inverted polarity, and you can just work around it, or build a little inverting FET or op amp circuit to add after (or inside!) the offending pedal to get your bass back. Many people don't worry about the polarity reversal thing. There is a list of polarity inverting pedals somewhere. The Gear Page? And you can skip the LED.
For the boost, add a booster (via a stomp switch) to the mixer output. Make sure it has at least a 1Meg to ground on its input so it doesn't pop when you kick it in.
On mine, I added stompswitches just after the individual mixer pots, connecting and disconnecting that leg of the mixer.  You can get that to function like a send/return looper, stomping one loop ON while stomping another off. But there I go with the bells and whistles again. [You mention this pedal that "gets real quiet". is the SHO just to correct the level of that one pedal?  Sounds like something is wrong with it but if that's your plan, never mind about the output boost I'm describing.]
Draw up a schematic of how it seems to together and post it here.
Would someone else like to chime in here?

[slacker]

Here's a single loop diagram



if you want to add the booster to the return remove the yellow wire between the return tip and the switch and instead wire the input of the booster to the tip and the output of the booster to the switch.

I'm not sure what you mean by a two channel looper but it might be as simple as wiring two single loop ones in series.

[aBunchOfPedals]

Here's a single loop diagram

if you want to add the booster to the return remove the yellow wire between the return tip and the switch and instead wire the input of the booster to the tip and the output of the booster to the switch.

I'm not sure what you mean by a two channel looper but it might be as simple as wiring two single loop ones in series.

This is what I'm talking about, nice and easy!  I just meant that instead of one loop, I can have two but only one would have the boost on it.  Is there a term I'm misunderstanding when I say two channel looper? 

[aBunchOfPedals]

Here's a single loop diagram


if you want to add the booster to the return remove the yellow wire between the return tip and the switch and instead wire the input of the booster to the tip and the output of the booster to the switch.

How should I wire the power? 

[blackieNYC]

[aBunchOfPedals]

I just want to pop in  and say I used the above diagram, inserted the SHO boost where the yellow wire was and ran the power cable to the SHO boost.  Works awesome!