Passive MIDI patchbay?

  • Thread starter Thread starter Krakit
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Krakit

Krakit

Rzzzzz!
I figure this would be the best forum to get an answer to this, even though I need it for a stage rig.

Does anyone make a passive MIDI patchbay? Something probably designed to mount into the wall of a studio space and come out the other side?

Barring that, anyone make an active MIDI router with at least four inputs on the FRONT and the other four (and all 8 outputs) on the back?

Or even more alternatively: Has anyone ever mounted some MIDI male to male conectors through a blank rackmount plate? How'd that work for ya?

Thanks in advance.

Carl
 
Krakit said:
Does anyone make a passive MIDI patchbay? Something probably designed to mount into the wall of a studio space and come out the other side?
Click to expand...

I have never seen one, as it violates the midi 1.0 specification.

Krakit said:
Barring that, anyone make an active MIDI router with at least four inputs on the FRONT and the other four (and all 8 outputs) on the back?
Click to expand...

JC Cooper makes an MSB+ (or did) that is an 8x8 midi switcher, however there are no jacks on the front. 360 systems used to make a 4x8 midi switcher, but again, no jacks on the front.

Krakit said:
Or even more alternatively: Has anyone ever mounted some MIDI male to male conectors through a blank rackmount plate? How'd that work for ya?
Click to expand...

Either of the above units (which I have, and found them quite useful over the years) will do the trick, and you can take a 1U blank panel, drill a bunch of holes in them, and install standard female 5-pin chassis mount connectors you can acquire from Radio Shack, Digikey, Allied Electronics or Mouser, just to name a few. Then wire those jacks to standard 5-pin DIN plugs, using shielded two conductor microphone cable (shield to the center pin on the jack, but not the plug, red to the left pin next to the center, white to the right pin next to the center) and plug that into either of the above units. Then you have your front mounted jacks.

If you can solder, you can make one of these. While the schematic is drawn with two inputs and two outputs, I actually built one of these with sixteen in and sixteen out, simply duplicating the parts as much as necessary, and using 16 position rotary switches instead of simple DPDT. This is my own design, but probably bits of it were stolen from somewhere, I'm sure. I sold it to a friend years ago once i acquired a plethora of emagic midi interfaces for my PC, as I can use them as both switch matrixes (routers) or in/outs on the PC depending what I'm doing at the time. 64 ins, 64 outs. :D

midi-patchbay.jpg


You're welcome to copy this design, expand it as you see fit, print it and set it on fire, whatever. I consider it public domain. The final version of my 16x16 midi switcher actually was all digital - the rotary switches went away, and I had a large dot matrix display in the center of the unit (256 LEDs) which indicated what was switched to what. Was significantly more expensive, but easier to see in a dimly lit studio. I have that schematic somewhere, if you want it, let me know and I'll see if I can find it.
 
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And here is the digital version... again, its not a complete schematic, but the building blocks of what I made. There was no memory aspect, so every time you powered it on all of the outputs "tapped" midi input one. For my needs, this was fine 99% of the time, which is why I never bothered to add a memory function, which wouldn't have been all that difficult to do.

Essentially, the 74LS150 can select one of sixteen inputs, based on BCD inputs, and output the selected input, inverted, to "W" which drives the midi out port though a few resistors.

The 74LS154 is also a BCD selector, except its the other way around. One input, 16 possible outputs. This is what drives the LED matrix for each midi output, so that only one led per output channel is lit at any given moment.

The 74LS154 has an inverted enable input, which is grounded, not sure if that's shown in the schematic or not. If you want the LED's to blink with traffic, instead of grounding the inverted enable input, you can tie it to the inverted "W" output of the 74LS150. This is what I did, so the LED's blinked wildly indicating midi traffic of some kind. Again, that's not in the schematic.

For midi-related stuff I've always tried to use TTL where possible, instead of cmos devices, because static electricity can damage cmos devices and I never wanted to rework the final assembly. Built, install, forget about it.


Boring, simple, TTL logic. Again, public domain design I did a decade ago, feel free to build this, print and set on fire, etc. No warranty expressed or implied, as its not a for-pay design nor is it complete.

Not sure you want to build something like this, but feel free if you wish.


midi-patchbay2.jpg
 
I appreciate this Fredric, but I've got to say with all due respect that you're overcomplicating my situation.

I already have a very nice MIDI router (it's in my rack). A MOTU Express. 8 ins and 8 outs. Unfortunately, all but one in and one out are in the back of the unit and I've just upgraded rack cases.

I've installed my gear into an SBK DJ case designed for a mixing board. I'm not using it that way though. I got creative and stand it on it's back with the top facing me. I've dropped my synth modules into what is now the top and my effects and MIDI router down what is now the front. Ergonomically it's fantastic for me. Unfortunately, the only opening is a removable panel on what is now the bottom. All of my outboard gear is wired through this opening.

So, I'm going to install a cheap patch bay for my phono jacks (patched into the line mixer) and it looks like I'm going to be creating a similar thing for my MIDI inputs.

I think I'm going to buy a Raxxess S16 and four MIDI male to male connectors. I'll improvise a way to fasten the connectors flush with the plate. Inside the case, I'll patch some short MIDI cables to my MOTU Express.

I was hoping that something like that already existed, but I guess I'll be able to get by with this adhoc creation.

Carl
 
Krakit said:
I appreciate this Fredric, but I've got to say with all due respect that you're overcomplicating my situation.
Click to expand...

That's me, Mr. Overkill!

Krakit said:
I already have a very nice MIDI router (it's in my rack). A MOTU Express. 8 ins and 8 outs. Unfortunately, all but one in and one out are in the back of the unit and I've just upgraded rack cases.
Click to expand...

Well, like you said, making a panel is probably your best option. Most blank 1U panels are aluminum which is easy to work with and drill nice round holes in.

Krakit said:
fantastic for me. Unfortunately, the only opening is a removable panel on what is now the bottom. All of my outboard gear is wired through this opening.
Click to expand...

Sounds like a lot of my stuff!

Krakit said:
So, I'm going to install a cheap patch bay for my phono jacks (patched into the line mixer) and it looks like I'm going to be creating a similar thing for my MIDI inputs.
Click to expand...

Actually, if you have a 1/4" patch bay already, you can wire up some of the 1/4" jacks to your phono jacks on the equipment inside, and use some of the 1/4" jacks for midi, as long as they are balanced, i.e. TRS.

Midi, like balanced audio, uses three connections, so you could buy midi patch cords, cut them in half, and solder on ordinary stereo (TRS) 1/4" phone plugs. That probably would be less work than drilling out panels trying to get all the jacks to line up nicely.

Just a thought...
 
frederic said:
Actually, if you have a 1/4" patch bay already, you can wire up some of the 1/4" jacks to your phono jacks on the equipment inside, and use some of the 1/4" jacks for midi, as long as they are balanced, i.e. TRS.

Midi, like balanced audio, uses three connections, so you could buy midi patch cords, cut them in half, and solder on ordinary stereo (TRS) 1/4" phone plugs. That probably would be less work than drilling out panels trying to get all the jacks to line up nicely.

Just a thought...
Click to expand...

Actually, if I understand what you're saying I would have to make some custom MIDI cables for my outboard gear that terminates in TRS phono jacks.

The rub there is that if I forget or break a cable there's no ready made solution at the local music store before the gig.

It's safer for me to keep it defacto. It shouldn't be that hard to do. The s16 already has holes in it for XLR inputs. I'm going to fashion some sort of grommet that will hold the adapter in place. Perhaps I'll thread the ring around the MIDI plug and screw it on with a thin nut.

Carl
 
Actually, I may be overcomplicating things myself! I think I'll just buy and mount 5 MIDI Din sockets to a rack mount plate. Cut three MIDI cables in half (throw one half away) and solder them to the backsides of the Dins (remembering to slip the shrink tubing on FIRST! :D ).

Perhaps, I could wire up some quarter inch phono jacks the same way on the other half of the plate?

That would do it all for me in a single rackspace for lots less than the cost of even a Behringer patchbay.

Carl
 
Well, one thing is for certain. I'm not the only one that has had a similar dilemma and tried to solve it himself.

<click me>

It's too bad this isn't even a close match to what I ultimately need. However, it's nice to see that this is more than just a little doable.

Carl
 
Here's where I stand so far.

I've recieved almost all of the hardware that I need for this project. I'm still waiting for two MIDI connectors that were backordered and didn't ship with the other four.

So far I've goten three MIDI connections soldered and tested (three more to go) and one of the ten quarter inch phono jacks soldered and tested.

At this rate it should take me a few more days (don't have much time to spend on this) to finish.

I'll take some pictures when I'm done.

Carl
 
There ya go, seems to have worked out for ya.

And you could have used the TRS patch bay with custom cables, and since you're worried about cables going bad (valid concern) make 3 more and bring them with you.

It sounds like you're on the road a lot... if that's the case I'd toss in a cheapie radio shack soldering iron and some solder "just in case". Not that you want to spend time from setting up, soldering cables, but if your very last cable went kaput, it beats trying to source one locally.

Just a thought.
 
Well, I'm taking my time and soldering the right way (no cold joints). My big concern here is stress releif.

There's really no place to provide any. At least not in such a way that just taking my adhoc patch bay out won't cause even more stress.

There's no room behind the rackspace for any additional parts on my patchbay.

I guess I'm just going to have to depend on my soldering skills and shirnk tubing to keep my connections from breaking.

Carl
 
Krakit said:
There's really no place to provide any. At least not in such a way that just taking my adhoc patch bay out won't cause even more stress.

There's no room behind the rackspace for any additional parts on my patchbay.
Click to expand...

Well, draw all the cables from one side of the patch bay, and tie them together with a wire tie through either a bolt-on or stick-on wire tie holder. Then the flex is at that point, rather than right at the jack terminals, preventing torquing of your solder joints. Then run the cables close to the patch bay panel, then to the jacks, cut to fit, solder, and you're good to go.

I do this with most patch bays I assemble, draw cabling from one side, to prevent flex near the jacks.
 
I've come up with a way to provide stress relief for the MIDI cables at least.

I'm going to use a tie wrap near the business end of the cable.

When it's nice and tight (but not too tight) I'm going to then thread the same tie wrap through one of the eyes of an unused pin (these eyes are oval). Then I'm going to take the lock nut from a second tie wrap and send the tail end of the first tie wrap through it until it catches. Rinse and repeat.

There are no such pins on the quarter inch inputs so I'll have to come up with something equally useful for those.

Giving it thought as I type.

Carl
 
Here's some shots of the finished and tested project:


image0300mj.jpg


image0318bo.jpg


image0325jj.jpg


image0332xn.jpg


image0344hj.jpg


image0353dr.jpg


Thanks for the help.

Carl
 
Looks like you handled business..got a parts list handy for the MIDI stuff?
 
Glad the thread has been woken up again as I'm looking for similar solutions myself.
Thread #2 and #3 by Frederic mentions schematics which are no longer visible here. I've tried to PM the poster to no avail.

If anyone reading has these schematics, could you please repost them here?
 
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