DIY Dual Source TRS-to-Two-TS cables

[euraquilo]

Mornin' folks!

I have read that some of you assemble your own cables and I have been wondering if anyone makes their own TRS-to-Dual-Mono cables. I have hunted for something exactly the way I want them, but generally the only ones I've found have been a bit expensive. I like do-it-yourself projects, so I've come up with a scheme to make my own, but I have one potential glitch...

I would take a quality mono instrument cable with the kinds of plug ends I want, cut it in half, strip it back for the lead & ground. Then I'd take a TRS (3 conductor) cable, cut it at the desired length, strip it back and connect the appropriate hot leads to the two pieces of the mono cables.

Tip ----> Tip of one mono cable (soldered and covered with shrink tube)
Ring ---> Tip of the other mono cable (soldered and covered with shrink tube)
Sleeve --> Common to both mono cables

These would all be covered with shrink-tubing for protection and strength.

The only "gotcha" (at least in theory) is that the junction point would be exposed to potential RF/Hum/Buzz.

I could imagine using some kind of aluminum tape around the junction, then covering the whole section with shrink tube. Or maybe use some small metallic box (like a mini altoids box, along with rubber grommets to protect leads?) to shield it at that vulnerable spot.

Has anyone else tried doing this?
Any tips/tricks you've tried that works?
Is it really not necessary to worry about shielding it?

[AndyC]

Why make life so complicated??

Just use a Y splitter cable from a TRS socket at the end - if you need to customise that, it's easy.

[euraquilo]

I fully respect that not everyone will find this issue interesting - some may see it as cumbersome and unnecessary. But there are some of us who, for reasons of limited budget and/or for the joy of the challenge and the learning, would rather grapple with and overcome through ingenuity.

I don't really need to defend my question - it's not for everyone.

[Doug Young]

I think your idea sounds fine. Looking at the Y cables I have, I see a couple of approaches:

1) 2 shielded single-wire cables. Connect to a TS plug at one end of each, connect the other end to a TRS plug, inserting both thru the plug cover. You can tape the cable at intervals to make it more like a single cable for most of the run, depending on how long you need. I have the Parker cable that's done like this, tho the 2 lines are a "dual" cable that mostly joined together instead of having to tape them together.

2) a 2 wire+shield cable connected to the TRS plug, then solder 2 shorter 1-wire+shield to the respective lines and cover the junction with shrink wrap. I have fairly pricy cable that's done like this. I can't see under the "shrink-wrap", which is more of a rubber sleeve on this cable to see if they did shielding of the junction, but I've seen other cables like this where they didn't bother. I've not noticed any noise pickup from this.

3) A Y adaptor. Do a very short Y cable using either approach but have the TRS side be a jack instead of a plug and use a TRS cable between the source and the adaptor. For example, if you only need the Y part to be 6 inches long, you could use approach 1 for a very short, thinner cable, then use a heavier TRS cable for the longer cable run. This could also be done as a breakout box instead of a cable, depending on how you're going to use it. Basically, TRS jack to 2 TS jacks inside a box of some kind. I'm about to do something like this for a pedal board setup.

[euraquilo]

Thanks for the summary, Doug. Sounds like #2 is closest to my scenario. It sounds like its worth trying it out to see if shrink tubing is enough. I always bring spares to a gig anyway so worst case is I trade it out after a sound check.

I've thought of doing your #3 approach, too. I found some small metal cups that I though I could drill three holes into, wire in the jacks, then find some way to seal the bottom for shielding. It would have the advantage of allowing flexibility in terms of what length cables I plug into it.

[shufflebeat]

Screened "fig 8" cable would be quite an elegant solution:

[euraquilo]

Originally Posted by shufflebeat

Screened "fig 8" cable would be quite an elegant solution:

I don't see the image you posted.

[shufflebeat]

Mmm, me neither.

Anyway, screened fig 8 - google it.

[euraquilo]

Woah, that fig. 8 reference led to a series of google detours that brought me to this. It looks like exactly what I was seeking.

Edit: The more I look at it, the more I think it might not allow for cable thicknesses I plan to use. It says the single hole is 5mm and the splitter holes are 3.2mm. I'll need to check out my cables when I get home.

[euraquilo]

Originally Posted by euraquilo

Woah, that fig. 8 reference led to a series of google detours that brought me to this. It looks like exactly what I was seeking.

And the picture...

[dcopper]

I took two George L cables with mono ends and soldered them to a stereo jack to make a Y cable.
They worked fine. I also have a Mogami TRS to TRS and use a Y mono/mono adapter.
Those were two options that took very little effort.

[euraquilo]

I've been making some progress, and coming up with some alternative ideas to my original plan. Right now I'm finishing up one of those.

I reasoned that in my circumstances I'm unlikely to be playing in a gig where I would be utilizing both pickups (the jjb SBT and the Sunrise magnetic) at the same time, but I still have a TRS output jack on all my guitars. I'm thinking the SBT would be the likely choice for smaller rooms/lower volumes where feedback would be less of an issue. The Sunrise would probably be better in larger venues or in ensemble work.

My idea was to create an adapter that allows me to easily switch between the two.

See picture. I've placed a single jack in a small extruded aluminum casing, with a TRS cable coming in (via a rubber grommet for strain relief) and a DPDT switch to enable sending either the tip pickup (the SBT) or the ring pickup (the Sunrise).

My question before I solder in the connections is this (because my knowledge of electronics is minimal): Can I solder the ground from the TRS cable directly to the output jack or should I send it through the DPDT switch?

Thanks to anyone who might still be listening.

[euraquilo]

Originally Posted by euraquilo

And the picture...

Incidentally, these little buggers turned out to be too tiny for the kinds of cabling I use.

[euraquilo]

Originally Posted by euraquilo

My question before I solder in the connections is this (because my knowledge of electronics is minimal): Can I solder the ground from the TRS cable directly to the output jack or should I send it through the DPDT switch?

A little research today and I've uncovered the wiring diagram I need (and it's different than I thought it would be!). Can't wait to see if the idea works!

[HHP]

My trick for these is to spend a couple bucks and buy a Y-cable.