Author Topic: Random access effects loop switcher???  (Read 3174 times)


Random access effects loop switcher???
« on: January 21, 2009, 12:21:09 AM »
I have a couple project ideas in which I need a switching circuit to choose between one of a number of loops, one at a time, and in some applications, the option to turn the currently selected loop off. Confused?

The first and simplest project is a box that has three stomp switches. It will have input, output, and three sets of send/return jacks. Each footswitch will correspond to one of the three loops. I want to be able to turn on any loop by pressing the corresponding footswitch. If I want to switch from loop 1 to loop 3, for example, this is done by pressing the #3 footswitch, which activates loop 3 and at the same time bypasses loop 1. To bypass all loops, press the footswitch for the currently active loop.

Does that make sense? Random access, only one loop on at a time, and select the active loop for total bypass.

I only have basic knowledge of audio path electronics, so this whole electronic switching stuff is pretty foreign to me. Can anybody help me out?


Re: Random access effects loop switcher???
« Reply #1 on: January 21, 2009, 06:29:30 PM »
Hi I think I understand.
It's fairly easy programming actually and I could maybe do a little "hack"... but there is a mcu stuck in my programmer right now and I don't know how to get it out (I'm seriously thinking of cutting off the legs one by one   ;D  )

If you want to do it yourself you can simplify the task as follows.
Make the bypass a separate function, so that you select loop 1-3 and then bypass ( simply a shorted loop ) with a separate button and then again re-choose the wanted loop, it would make for much easier construction. The four buttons would have only one function each and the same "priority".


Re: Random access effects loop switcher???
« Reply #2 on: January 21, 2009, 07:07:17 PM »
I once rigged up the logical circuitry for something like that with some flip flops and some diodes

you could also do it with latching relays


Re: Random access effects loop switcher???
« Reply #3 on: January 21, 2009, 08:52:30 PM »
I had a go at it. Off course RG has solved this allready (check GEOFEX, he has a big chapter on switches), but I had to do it my way.  :)
There probably are more suitable circuits than the 4013 for the job but that's the one I allways use.
From left to right:
The switch pulls the input of the inverter low when engaged which A:toggles the state of it's flip-flop(4013) and B:resets the other flip-flops. R/C values are suggested values only.
Maybe you can do away with the inverters... I don't know... It's the multifunctionality of the switch that makes it more complex (for my poor CPU anyway    :P )

The other way, if you choose a separate switch for bypass, will be lower in parts count. Only two 4013 and a bunch of diodes.
Tear it to pieces boys and girls...  ;D