MIDI to TRS cables/Noise

[Alex Kenivel]

I finally have my Strymon Brig affixed to my board and in my signal chain where I want it to go, but am having an issue connecting it to my MIDI chain -- I get a beating hum through my amp. The weak link seems to be between the Suhr MicroMIDI Control and the One Control MIDI Hammer I've turned into a MIDI-TRS cable that I am plugging into the Brig from the MMC.

MIDI chain is Paint Audio Midi Captain>HX Stomp>Suhr MMC>Brig.

I used this diagram to make the cable:

One thing I noticed about the MIDI Hammer is that only pins 4 and 5 had wires coming from them, no shield. Maybe I'm getting noise because there is no shield??

MIDI Cap'n > DIY cable > Brig works fine so I think I've wired it correctly as far as MIDI A/MIDI B wiring goes (this would be MIDI B if I'm not mistaken).

 

[laxu]

Can the Suhr MMC even support MIDI TRS jack? The manual and product page are kinda vague about this.

I tried looking at the Suhr Alexa documentation as that is used as an example for the Fx link, but it seems that's a standard TRS footswitch type connection rather than MIDI.

 

[Baba]

God bless you brother. I'd be clicking buy it now/put in cart, long before I'd be dealing with something like this.

 

[Alex Kenivel]

Can the Suhr MMC even support MIDI TRS jack?

Sorry if I wasn't clear. The cable is a 5-pin DIN to TRS. 5 pin side plugged into the MMC, TRS for the Brig. Is there some protocol mismatch I'm missing here?

 

[laxu]

Sorry if I wasn't clear. The cable is a 5-pin DIN to TRS. 5 pin side plugged into the MMC, TRS for the Brig. Is there some protocol mismatch I'm missing here?

I honestly don't know.

I'd try connecting the shield and see if that fixes the issue.

I currently use a EBS flat TRS -> 2x TS cable to control my Strymon Riverside + Compadre from one jack on my Strymon Conduit. I ran out of jacks on the Conduit so I decided which pedals are ok with MIDI input only so I don't have to be able to track their values for example in my Luminite Graviton M1.

 

[Alex Kenivel]

I'd try connecting the shield and see if that fixes the issue.

There's no shield cable wire, that's what was throwing me off. That may not be the issue anyway...

Today is my day off so I got down and started troubleshooting more and the problem may be coming from the MMC itself.

As per the video below, when I push down on one side of the MIDI IN cable, the noise goes away and CC control resumes normally. When I let go, the noise resumes and CC messages are skipped.




I tried a bog standard midi cable and noise was still there. Wasn't able to push on one side to make the noise go away though.

I'll send this video in to Suhr to see what they think...

 

[Alex Kenivel]

Still waiting to hear back from Suhr...

Decided to rip the board apart and and play Legos with the pieces, trying different things. Placing the MMC before the Stomp and the Brig after makes the noise go away. I'll just have to either completely reconfigure my board or figure out a way to either lengthen or just make another MIDI DIN/TRS cable.. The one I have is probably going to be a little too short now.

Fml this is exactly a big reason why I went full digital in the first place

 

[Alex Kenivel]

Gonna try to extend my cable with some bog standard wire and see where that takes me.

 

[SillyOctpuss]

Good luck dude.

Man I hate the roller coaster ride of trouble shooting. It's a fucking amazing feeling when you finally fix a problem though.

 

[Alex Kenivel]

It's a fucking amazing feeling when you finally fix a problem though.

indeed it is.

After lengthening the cable with some wire I had laying around from my last pedal build my new(er) MIDI hodgepodge cable is complete and running the Brig no problem, no noise.

As a bonus, running the microMIDI before the Stomp makes the process of changing Stomp presets along with amp channels A lot quieter and quicker.

Edit: pictures are too damn big! lol

 

[SillyOctpuss]

 

[Baba]

Fml this is exactly a big reason why I went full digital in the first place

I hear that man. Nothing like a bunch of components in the chain to make you want to ditch it all and use an all-in-one unit.

 

[quadgear]

It seems like you had a ground loop issue.

When you pushed on the plug you possibly added yourself as a ground or flexed the connection so the ground contact disconnected.

Changing the order of devices, a cable, or power supply/wiring can add or break ground loops. Suspect that's what you did.

Midi spec requires an opto isolator on inputs for this reason, but for TRS implementations this is often skipped (sometimes because the port also supports expression pedals and other uses).

Two good articles on making this type of cable.

Note in the first one that the ground is left disconnected (floating) if the TRS is plugged into an input (and connected if plugged into an output). Also note the braided shield on the cable (but I not sure that's your issue).

Make your own 3.5mm TRS to DIN5 MIDI cable

3.5mm or 6.35mm TRS MIDI is getting more popular, evident in many MIDI devices from Chase Bliss, Meris and Morningstar (The MC3 MIDI Controller has 4 3.5mm MIDI Outs, and the MC8 has 4 6.35mm MIDI Outs).Getting a custom DIN5 to TRS cable might be expensive. In this article, I will show you how...

www.morningstar.io

[Updated] How to Make Your Own 3.5mm mini stereo TRS-to-MIDI 5 pin DIN cables

Editors note: This article was written before the MMA published an official standard for using TRS adapters with MIDI devices, and simply describes the TRS connectors that exist in the market. Future [...]

www.midi.org

The last one has the diagram you previously posted. It does not show the floating ground for the input side.

Finally there are multiple conventions for TRS midi wiring which change what pins attach to T, R, and S. Of course you know that.

 

[laxu]

Yeah Strymon's own 5-pin to TRS cables include the opto isolator but the cables that come with the Strymon Conduit MIDI hub don't, probably because that is implemented in the Conduit.