Making an A/B/C switcher?? Can anyone help me out?

IvisonGuitars

I'm thinking about making a custom switching unit for my rig.

Basically I want to use one guitar lead for my electric & electro-acoustic into my tuner, then split the signal so I can either send the acoustic straight to a DI or when playing the electric, switch it into a two amp set up.

(This is already sounding confusing to me!)

So basically if it was in front of me, from L to R I'd want:

A switch to A/B between amp channels
A switch to select the second amp
&
A switch to bypass the amps and send the signal to a DI

Im keen to make this myself as it'd be my first electronics project so is there anyone who could help me out with a 'Fisher Price - My First Schematic' type diagram etc?! Or perhaps just a bit of advice

Sporky

The way to do this (or at least the way I did it when I made custom routers) is to start with a functional description of the system.

What are the outcomes you want, in terms of input x to output y?

It sounds like the simplest thing would be to have two tuners and an AB switch for the electric. That'd save an awful lot of faffery.

ICBM

Sporky said:

It sounds like the simplest thing would be to have two tuners and an AB switch for the electric. That'd save an awful lot of faffery.

+1, and the risk of accidentally DI'ing the electric or running the acoustic through the guitar amp, or the need to mute everything when swapping guitars.

Unless you deliberately intend to DI the electric or distort the acoustic, keep the two systems completely separate.

IvisonGuitars

Thanks for the input chaps, I used to have exact that set up but it was a faff having two guitar leads/two tuners on stage.

I currently run one lead into a tuner, through my boost, into an A/B that selects between Amp & DI.

I want to be able to use the two channels on the amp (a Lazy J40/DC30, neither with intern switching) and a second amp too. Perhaps the easier option is another A/B box?

ICBM

Essentially what you need is A/B 1 (> DI or A/B 2 (> amp 1 or A/B 3 (> amp 2 channel 1 or amp 2 channel 2))). You could do it with three separate A/B boxes, or build it all into one box if you wanted.

IvisonGuitars

ICBM;10136" said:

Essentially what you need is A/B 1 (> DI or A/B 2 (> amp 1 or A/B 3 (> amp 2 channel 1 or amp 2 channel 2))). You could do it with three separate A/B boxes, or build it all into one box if you wanted.

Yes, that's about the size of it..if I were to use 3 A/B boxes, how would I wire them to work together/switch independently?

I'm willing to use a bit of trial and error as it'd be cheaper than a phone call to Pete Cornish!

IvisonGuitars

ICBM said:

Essentially what you need is A/B 1 (> DI or A/B 2 (> amp 1 or A/B 3 (> amp 2 channel 1 or amp 2 channel 2))). You could do it with three separate A/B boxes, or build it all into one box if you wanted.

Or, to perhaps simplify things, an enclosure with 4 foot switches on, each wired to turn of the previously selected one. Like a simple amp switcher, surely that would be easier?

ICBM

miserneil said:

Or, to perhaps simplify things, an enclosure with 4 foot switches on, each wired to turn of the previously selected one. Like a simple amp switcher, surely that would be easier?

No, that's much harder - it requires electronic logic control, whereas three A/B switches can be done with mechanical DPDTs.

chillidoggy

I contacted Steve at Swift Pedal, he got my similar set-up sorted in one pedal PDQ, and it wasn't expensive.

IvisonGuitars

Cheers @chillidoggy, I'll give him a shout

mike257

It sounds like three stacked A/B switches is what you need, like ICBM said, so it's actually pretty simple.  Even if you build it in one box, you'd just hardwire an output from one into the input of the next one.

A/B box 1 into (A) D.I box

(B) Second A/B box into (A) First amp

(B) Third A/B box into (A) Amp channel 1

(B) Amp channel 2

Dead easy!

EDIT: Laid this post out with loads of tab spacing to help it make sense, but just realised it'll probably look like nonsense on a mobile browser, so sorry if that's how you're viewing!

IvisonGuitars

mike257 said:

It sounds like three stacked A/B switches is what you need, like ICBM said, so it's actually pretty simple.  Even if you build it in one box, you'd just hardwire an output from one into the input of the next one.

A/B box 1 into (A) D.I box

(B) Second A/B box into (A) First amp

(B) Third A/B box into (A) Amp channel 1

(B) Amp channel 2

Dead easy!

EDIT: Laid this post out with loads of tab spacing to help it make sense, but just realised it'll probably look like nonsense on a mobile browser, so sorry if that's how you're viewing!

Ah right, thanks @mike257, I think I get the just of what you and @ICBM were saying, I may just give this a try and see how I get on

Sporky

I wonder if using an Arduino or similar would make a logic-switched approach the better choice. Hmm.