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Question on building effects looper pedal
Posted: Tue Jul 07, 2009 8:20 am
by TideBleach
I just got a boss rc-2 looper and I have a question on what kind of looper/aby box thing I need to build to be able to switch the Boss RC-2 from 2 different amps, so i can have a dedicated looper amp and a live amp. I'm running the RC-2 into my JCM900 effects loop and would like to be able to switch to my Fender vibro champ at will. I hope this makes sense lol, I think I might be over thinking this a little bit.
thanks!

Posted: Tue Jul 07, 2009 8:24 am
by Mike
You just want to be able to flip the output of the Looper between the JCM900 and your Vibro Champ?
Posted: Tue Jul 07, 2009 8:37 am
by TideBleach
Yeah flip the output of the RC-2 so i can switch amps on the fly. So I can use distorted loops on the JCM and clean loops on the vibro champ. I'd like to be able to set a loop and have it play rhythm on one amp and then I can play lead stuff on the other. Sorry i'm a bit slow tonight running on barely any sleep, i'm gonna read this in the morning and wonder what I was rambling on about.
Posted: Tue Jul 07, 2009 10:12 am
by Mike
That's more complicated that just switching the RC-2 output.
If you want the same loop to switch between amps then you record the loop and use an A/B box to select what amp it's going to, however if you want to then play over the loop through the other amp, then you need to have another box which switches your guitar into that amp.
It's not simple (at all). You would need an A/B box flipping the output of the RC-2 between the amps, and if you want to play through the same amp the RC-2 is, then that's fine you just play, but if you want to leave the RC-2 running on that amp and then play through the other, you need the box that has disabled the RC-2 to an amp to be able to pick up your guitar signal prior to the RC-2 and feed it to the unused amp.
If you don't have a stereo pedal with a spare output before the RC-2 this means the box will have to take the signal and buffer it at this point before feeding it back into the RC-2. It ain't simple.
Posted: Tue Jul 07, 2009 1:58 pm
by TideBleach
Yikes that's what I was afraid of, it is a lot more complicated then I was hoping it would be. Do you know of any schematics for a box that would do all this? I've modded a few pedals and know my way around with a soldering iron a little bit. thanks!
Posted: Tue Jul 07, 2009 2:04 pm
by Mike
Nope. It would have to be a ground up design as your implementation is very niche.
I could draw you up a basic schematic though if you want.
Posted: Tue Jul 07, 2009 4:18 pm
by TideBleach
That would be awesome, thanks.
Posted: Wed Jul 08, 2009 8:06 am
by Mike
OK I'll do it on paper and scan it for you at some point this week.
Warning: It will contain at least one op-amp buffer.
Posted: Thu Jul 09, 2009 10:31 am
by Mike
OK, before I give you the dirty information regarding the Buffer and switch wiring, is this the functionality you would like to have?
i.e. two switches, one sets the destination of the RC-2 to either amp A or B.
and you also choose where the GTR (or the end of your effects chain before the RC-2) goes, either into the RC-2 to record loops or overdub or play over on the same amp the RC-2 is going to, or to the other amp to play over the RC-2 stuff through the other amp.
Is this what you want?

Posted: Fri Jul 10, 2009 7:39 am
by TideBleach
That box would work great, but I was wondering if something like this would also be possible. I know it's a lot more complicated then I was originally looking for but if something like this was possible it would be even more perfect. So I would be able to choose where my loop goes and still use my effects into the looper. thanks again I really appreciate this!

Posted: Fri Jul 10, 2009 8:18 am
by Mike
Nah, you can't do that without mixing because your left and right footswitches can send signals to the Amps at the same time.
For example you could be trying to send RC-2 and your guitar to Amp 1 at the same time. That's not going to suond pretty.
Also "switches Effects to Amp1 loop or Amp2 input" is not simple either, again you're driving Amp2 input from a THIRD footswitch.
I think the way I have done it is the only real workable solution, I don't think the one you've drawn there is possible (without several active mixer stages), or particuarly useful if I'm honest.
Posted: Fri Jul 10, 2009 8:27 am
by TideBleach
Ya looking at it now I went a little overboard on that lol, would be neat but in reality way more then whats actually needed. But your original design will work perfect and does exactly whats needed! so with your design i can (example 1) set a loop and leave it playing on amp 2 and play live with amp 1 right?
Posted: Fri Jul 10, 2009 8:45 am
by Mike
yes, or vice versa.
Also if you use the "GTR" as the back end of your effects chain you can have effects recorded to the RC-2 loops or played on the other amp....
Posted: Fri Jul 10, 2009 9:29 am
by TideBleach

well its settled then thats exactly the pedal I need, woot. sorry if anything I type is a little loopy* no pun intended I just got my wisdom teeth taken out and im still a little out of it XD
Posted: Fri Jul 10, 2009 9:31 am
by Mike
OK, I'll knock up the switch connections and a Buffer veroboard layout for you today.
Posted: Fri Jul 10, 2009 10:38 am
by Mike
LED switching on the switches ommitted, if you're planning to build this I'm sure you know how to do that. You might be able to omit the Buffer and just connect the GTR input jack to the Buf Out connection on the switch, but I have included it for completeness.
Posted: Fri Jul 10, 2009 7:21 pm
by TideBleach
nice
just out of curiosity how much would it be to have you custom make this for me? i've been meaning to order a made by mike pedal and this seems like a good time to order one.