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[George Reiswig]

Was recently trying to figure out a way to run a lengthy stereo line from a keyboard to a mixer. It occurred to me that since the sleeve connectors at the mixer Aux in are chassis grounds, I might be able to take advantage of that. And not using a DI box would also save me a couple of preamp slots on the mixer by using the Aux ins. So here's my idea:

• Make a couple of adapters that convert the appropriate gender XLR to a pair of TS 1/4" male at both ends of a mic cable
• At one end, don't hook the 1/4" sleeve up to the cable shield, to avoid ground loops.

Is that one of those ideas that looks OK on paper, but isn't?

[Russell Ault]

Was recently trying to figure out a way to run a lengthy stereo line from a keyboard to a mixer. It occurred to me that since the sleeve connectors at the mixer Aux in are chassis grounds, I might be able to take advantage of that. And not using a DI box would also save me a couple of preamp slots on the mixer by using the Aux ins. So here's my idea:

• Make a couple of adapters that convert the appropriate gender XLR to a pair of TS 1/4" male at both ends of a mic cable
• At one end, don't hook the 1/4" sleeve up to the cable shield, to avoid ground loops.

Is that one of those ideas that looks OK on paper, but isn't?

...I'm not sure it works on paper. I see two problems:

• The ground connection on a TS connector is also the signal return path, so lifting the ground means that no audio can flow
• "Lengthy" and "unbalanced" are not words that typically belong together in the same audio-related thought

Can you just run the keyboard mono? Does the keyboard have balanced outputs? (That will save you the DIs, at least, and possibly the mic pres if your console's aux inputs are also balanced.)

-Russ

[Ike Zimbel]

Was recently trying to figure out a way to run a lengthy stereo line from a keyboard to a mixer. It occurred to me that since the sleeve connectors at the mixer Aux in are chassis grounds, I might be able to take advantage of that. And not using a DI box would also save me a couple of preamp slots on the mixer by using the Aux ins. So here's my idea:

• Make a couple of adapters that convert the appropriate gender XLR to a pair of TS 1/4" male at both ends of a mic cable
• At one end, don't hook the 1/4" sleeve up to the cable shield, to avoid ground loops.

Is that one of those ideas that looks OK on paper, but isn't?

About 1000 years ago, well at least during the last millennium, I had that exact arrangement (minus any cleverness with the shields). I think I might have come up with it to make two unbalanced returns out of one XLR line at a club, but the details are lost to the mists of time. In any case, I survived, had a career etc. so I think for the time it will take you to solder it up, it's worth a try.

[duane massey]

In the past I have used the "pseudo balanced" method, but I don't that would apply. I am assuming (1) you are using a snake with XLRs; (2) the aux inputs are unbalanced. If so, use pins 2 & 3 for TS, and connect #1 to sleeve at both ends. If you have a ground loop, try clipping the connection to #1 at mixer end. Might work, might not.

[George Reiswig]

From what I've known in the past, lengthy, unbalanced and line level go together fairly well. But I do take the point about the return path for the signal.

I have the connectors..I'll probably give it a try with the shield hooked at both ends and see.

[Jordan Wolf]

...And not using a DI box would also save me a couple of preamp slots on the mixer by using the Aux ins. So here's my idea:

What make & model is the mixer? Most have Bal/Unbal Aux inputs.

You could use something like a ProCo iFace to balance the signal and get it up to Line Level and then go XLR to TRS into the console/s Aux Inputs.

[Russell Ault]

From what I've known in the past, lengthy, unbalanced and line level go together fairly well.  {...}

It certainly can work; ClearCom and RTS party-line intercom and both examples of unbalanced systems that work well.

The main issues with unbalanced signalling typically relate to induced noise/cross-talk and grounding issues (you may also run into some high-frequency loss due to inductance depending on the cabling and the distance). If you're sure everything is grounded properly then it might well work, but it wouldn't be a solution I'd personally recommend since it will be more likely to fail (in audience-facing ways) than any solution using balanced signalling.

I asked this before, but are you sure your keyboard doesn't have balanced outputs? It seems like a lot of keyboards these days do.

-Russ

[Paul G. OBrien]

A few years ago I made up a bunch of adapters to carry a stereo unbalanced signal over a single XLR "extension" and it has worked fine on numerous occasions to get audio from a laptop/projector combo to the PA system on the other side of a ballroom. I think I have used it on a keyboard or e-drum set once or twice too. But other times a source only a few feet away from the mixer produces noise or a ground loop hum and has to be isolated with a DI or transformer isolator(Art DTI). This is one of those cases where your milage really does vary because you are at the mercy of an unknown RF environment and you never know when you may encounter a piece of equipment with an underlying problem.

BTW.. the ART DTI is a great iso tool for stuff like this because it has XLR, TRS and RCA connectors on both input and outputs.

[Russell Ault]

{...} But other times a source only a few feet away from the mixer produces noise or a ground loop hum and has to be isolated with a DI or transformer isolator(Art DTI). {...}

+1000. This is all the reasons why I don't recommend this approach.

There's already enough that can go wrong in live sound even when I'm doing everything "right", so I try hard to not intentionally add things to the list.

-Russ

[George Reiswig]

Great input, all. Yes, I'll check to see if the keyboard has balanced outs. TRS 25' cables are like $15 on Amazon. A pair of those would be fine.

Mainly a theoretical question for me, but I might try these adapters anyway because I'm a curious guy.

[ProSoundWeb Community]