crazy pedalboard junction box idea

[bsmcc2010]

So basically i have this idea to create 2 little boxes. 1 sits on my pedal board with 2 input jack sockets (one from my FX and one from my footswitch out) and then has a 7 pin MIDI out. This box connects via a 7 pin MIDI cable to another similar box on top of my amp which has a MIDI in (from the cable) and 2 outputs (one to go into my amp, and one to go into the footswitch jack). My power supply for my pedal would be plugged in near my amp and also be sent down the MIDI cable via the 2 boxes.

From my limited electronics knowledge, i think this would work. The MIDI cable has 7 pins-3 for the footswitch (tip ring sleeve) 2 for the guitar signal (tip and sleeve) and 2 for my power supply (+ and -).

This would really tidy up my pedal board as there would be 1 cable coming from it instead of 3.

Just wondering weather this would actually work the way i'm expecting it too before i go ahead and make it.

[R.G.]

Any cable with enough conductors works.

I've speculated about using 8-conductor ethernet cable. Makes the cables cheap and easy to find.

The problems are with the usual analog stuff - hum pickup, voltage drop, crosstalk, etc. I thought I'd use the power to put a push-pull buffer in the remote pedal to eliminate hum and crosstalk on the way to the amp.

But that's just me.

[EATyourGuitar]

^this and DIN 7 is not as durable as a 1/4 jack. although you can get midi cables everywhere. you would want shielded cable for the guitar audio. running DC close to audio is usually avoided whenever possible. if you look at high end car stereo RCA cables, they make a double helix. that is the same reason you would put zip ties on your cables in the back of your hifi stereo so that power always crosses the audio at a 90 degree angle. its the right handed rule of flux. basic laws of induction and stuff.

[R.G.]

^this and DIN 7 is not as durable as a 1/4 jack.

Yep. However, it has the advantage of reliability the way nature does it with insects - cheap and easy replication.

although you can get midi cables everywhere.

There are even more places to get ethernet cables than MIDI cables.

you would want shielded cable for the guitar audio

Yes - unless you took the trouble to buffer the signal and run it as a balanced +/- signal in twisted pair, as I mentioned.

running DC close to audio is usually avoided whenever possible.

Actually, DC isn't a problem. It's AC power cables that are a big problem. If the cables have DC on them, proper decoupling at each end of the cable makes both the DC wires be equivalent to ground at frequency of interest.

put zip ties on your cables in the back of your hifi stereo so that power always crosses the audio at a 90 degree angle.

Those are AC power cables, carrying 120 - 240 Vac and amperes of current. DC cables are much, much less of an issue. There's the example of phantom power where the actual wire carrying signal carries the DC power.

[EATyourGuitar]

thankyou RG. very educational. reminds me of how electret microphones have two wires and they are always powered mics. they share a ground and the PCB usually has the cap in it to seperate the audio from the V+.


I have a bag of em collecting dust.

[harmonic]

... and how the signal AND the phantom power both go down pins 2 & 3 of an XLR cable.

[ashcat_lt]

I've ripped apart a couple of MIDI cables and they were shielded.  Can't promise that every one in the world is, but I think it's a safe bet.  MIDI signals would be somewhat sensitive to noise, and I think it's a good idea to keep the MIDI pulses "inside" the cable to avoid coupling to nearby audio cables.