Midi A/B Switch Box doable?

[Jerry Overstreet]

Jack, Blake, Ken et al with experience in this area. Is there any reason one can't build and use an A/B box to switch between 2 midi controller devices with midi OUT only ports by wiring female 5 pin din jacks and an HD 3 position on, off, on toggle switch?

I've spent a lot of time researching this online and most of the info indicates it's not practical. I have a case I can use, I'm quite sure I can locate the proper components and wire them all together, but not if it's not going to work.

I know most midi devices output 5V on one pin. I don't know how they will behave if 2 devices are wired to a switch.

I want to use this in my rigs where I might be playing steel or guitar through a mono G2M guitar controller, or a basic midi keyboard controller into the same Alesis midi sound module and switch between the controllers if/as required without having to disconnect/re-connect the midi cable.

Ea. controller has only a midi OUT port and neither has an on/off switch.

I know there are 2 into 1 midi merger devices available, but I don't see how that would work for selecting one or the other controller. The ones I see, like the Midi Solutions brand, don't include a switching function.

I guess I'm showing my ignorance here as I know only some basic things concerning midi, so I'd like input from those of you who are more knowledgeable with navigating and routing and the electrical/mechanical aspects. Some of you eat this stuff for breakfast and I'd appreciate your help if you feel up to it.

Here's a crude drawing of the A/B device concept.

[Scott Duckworth]

My thinking is you could do it with a DPDT switch. The grounds (earth) could stay connected to each other.

[Glenn Demichele]

MIDI is optically isolated, so you don't even need to connect the ground wires. A simple DPDT switch is all you need, like this:

[Jerry Overstreet]

Terrific diagrams Glenn. Thanks so much. JO.

[Tom Mossburg]

I used to have a small device called a midi merger that did just what you are looking to do. Probably still have it somewhere. You can probably find one pretty cheap if you do a search. Sweetwater has new one for $69. If you go this way make sure you get a merger not a thru box.

[J.D.White]

Looks like the same thing that Glenn posted & has a picture of how it was packaged. Also if you use a switch that has a center off - would mute the midi signal.

https://carillonaudio.wordpress.com/201 ... di-ab-box/

[Jeff Mead]

Hardly seems worth making one when you can buy one for $14.99

There are many others available - maybe try Radio Shack (or equivalent) or some of the specialist keyboard sites.

http://www.ebay.com/itm/MIDI-cable-AB-2 ... -kKJF9n1IQ

[Jerry Overstreet]

Thanks JD.

[Jerry Overstreet]

Well, I been searching online for about a month now Jeff. Never saw that or any other AB switching box for midi. Thanks for the link, I may go there although I don't eBay.

Anyhow, I've got midi sockets, wiring and jacks to make cables on order for pretty cheap. Already have the box and switch so I should be good.

[Jeff Mead]

Well, I been searching online for about a month now Jeff. Never saw that or any other AB switching box for midi. Thanks for the link, I may go there although I don't eBay.

Anyhow, I've got midi sockets, wiring and jacks to make cables on order for pretty cheap. Already have the box and switch so I should be good.

It's funny because a few years back (probably about 15!) I used a little box - I think it was the one in the attached picture although I think mine had a mini selecter switch - which was tiny, very cheap and one of a great many that were available. It seems there is less demand for them now. maybe because a lot of people are hooking MIDI up via USB instead of the "old fashioned" MIDI cables.

[Jeff Mead]

Also, you might find some useful information on this site (almost all of which is way over my head) but the gy who runs it definitely knows his stuff!!!

http://www.philrees.co.uk/products/mergebox.htm

[Jerry Overstreet]

Yeah, read a bunch of his stuff. Lots of articles and diy pages.

I first started out looking for a simple midi "Y" cable and discovered about the only place you could find them was in China or the UK. Nothing in the states and all the info indicated not a good idea as the messages would collide. That's when I began searching for an AB Box.

Yes, everything drives one to USB utility which is mostly useless to me in this situation as I don't want to use a PC with this stuff right now. I'm usually about 20 yrs. behind technology!

[Jerry Overstreet]

Thanks for your help everybody. The diagrams are great and I was able to wire the box pretty straightforwardly. There's still clean-up etc. to do and I may want to put it in a different box later on. But it will serve for now.

I also made 2 midi cables which turned out to be a real challenge and PITA. The pins are so tiny and I don't have enough hands, ["helping hands" gadget just a little help.] Won't be building any more of those.

The A/B function works just fine, but I found out in testing early on, that you don't want to switch controllers while one is still sounding or you end up with stuck notes and a power down and reset. Lesson learned.





Edit: The box worked fine but was a pita to set up. I had a little computer stand etc. but all the hook-ups were on the back and underneath the other gear.

I decided to just move the components into the engine turned panel that was already existing in a rack with the input jack and the G2M guitar midi interface. Much better this way with the midi connections on the front.

Still some things to hook up at the rear panels, but this arrangements simplifies things a bit and eliminates a couple pieces of gear. Always welcome when carrying a pedal steel rig, guitars and keyboards.

[Glenn Demichele]

Check out "active sensing". You turn this on on both your controller and synths. The controller sends a special ping periodically, and if the synths stop hearing it, they turn off all notes. It's designed to prevent stuck notes if a cable gets unplugged, and will fix your switch issue.

[Jerry Overstreet]

I will certainly look into that. Everything seems to be OK long as I don't switch while the synth is receiving messages. I'm learning as I go. Thanks for all your help Glenn.