3 way ABY?

[msurdin]

Hey,

I am trying to build a 3 way aby type switcher for a multi effects unit. I want to be able to switch between 3 different outs and be able to choose any of the 3 whenever.
Is this possible to do?

If I want to buffer all th outs should I run the buffer before the switcher or make 3 different ones for each out?

Thanks for helping!

[R.G.]

Can you clarify that a bit?

You have three effects, call them F1, F2, and F3. You want to be able to select one of the three at any time, correct?

How is that different from the Multi-Vol (http://geofex.com/Article_Folders/multivol/multivol.htm) if you just used a fixed volume for each one?

[Mark Hammer]

I am trying to build a 3 way aby type switcher for a multi effects unit. I want to be able to switch between 3 different outs and be able to choose any of the 3 whenever.
Is this possible to do?
If I want to buffer all th outs should I run the buffer before the switcher or make 3 different ones for each out?
Thanks for helping!

In principle, yes.  You could have three stompswitches, but the gits is that when A is oressed, whatever is going on with B and C is then cancelled.  One way to do this is via the sequential switch posted here: http://hammer.ampage.org/files/quadsequentialswitch.pdf  You'd have to adapt it for switching 3 things, however, and you cannot go randomly from A to C, then B, then C again.  You can only go A, B, C, A, B, C etc.

I suspect that what you'd really need for that level of random access is something that uses some combination of CMOS logic chips such that if B is active and you press A, it will suppress B and C, and if you then press C it will suppress A and B.

[R.G.]

I suspect that what you'd really need for that level of random access is something that uses some combination of CMOS logic chips such that if B is active and you press A, it will suppress B and C, and if you then press C it will suppress A and B.

You're exactly correct. The diode matrix and latch circuit in the multivol article do exactly that.

[msurdin]

Well to clarify it a bit more. Lets say i have 3 amps. A1, A2, and A3. For a certain song i might want to go to A1, then the next song A3, Maybe at the end of that song switch to A2.
I was thinking it could be easy to have a pedal to be able to switch between 3 outs. at any time and not effect any of the other channels.

[R.G.]

So you want a three way distributor?

Not a problem. The one-of-N footswitcher in the referenced article still does the logic. It puts out a logic 1 for whichever channel is active, 0 for the others.

All you need to do is a buffer - like the first stage of the Multi-vol - feeding three CMOS switches. The selector logic goes to the three switches, and only one of the three is activated at a time. A buffer after three switches makes for a nice clean drive to the amps.

After that, all you need is hum isolation; this will likely be a problem with three amps. The transformer isolated buffer sections from the hum-free ABY at GEO will do that. You could use relays too to break the ground from the unused amps, but you're prone to clicking when changing channels that way.

[Jaicen_solo]

If I remember correctly, I was after something very similar a couple of years ago, and again R.G came to the rescue.
If you do a search, there's some discussion of using this same technique to actuate relays, which I'd prefer over CMOS switches.

[msurdin]

I was sitting at work and thought why not build 2 aby boxes. Then take aby 2 and wire it into the A channel on aby 1...
Would this work?
Obviously 3 outs.
I was thinking about this for awile. It seems a pretty simple idea. Just getting the wiring down so I dont have 1 usless switch