I've done my research on this (really), read the Rane "Note 110", and I'm not getting the expected results. Here's the situation:

I have a bunch of TRS cables and only 2 TS cables but I have over a dozen gear to mixer connections that I need to patch up. Thus, I want to use these existing cables to connect my unbalanced synths to my balanced mixer so that I don't have to spend more time + money to buy + make TS-TS cables. But I don't want the -6dB drop that happens by connecting the TRS cables "as is" to unbalanced gear.

I've modified a couple of these TRS cables to comply with the connection method #14 in the Rane Note 110. To summarize, the mixer end is left in the normal balanced TRS config and the synth end has the tip wire to jack tip, the ring wire to jack sleeve, and the sleeve wire is not connected.

Here's what I get in the various configs, from synth to mixer:

- TS to TS = sounds great (but I don't have very many TS cables)

- TRS to TRS = sounds great, but -6dB low

- TRS (modified) to TRS = same level as the TS-TS cable, but TONS OF HUM. It's completely unusable, and the hum gets even worse if I touch the jack sleeve of the synth end (no effect touching the jack of the mixer end)

I have gone over this and over this and read dozens of threads, but I can't figure out why this is not working.

I've also tried the less desirable method where the jack ring is bridged to jack sleeve on the synth end, and that resulted in lots of hum as well.

Help? I feel like I am really missing something since I see this method recommended so much, but I'm getting terrible results. My cable is Canare L4E6S Star Quad and jacks are Canare F16.

(and in case it's not obvious, yes I know I could just wire them up as TS on both ends and leave the ring wire completely disconnected but if I'm going to do that I'd rather just get TS jacks and do it right. I really do want to make use of the TRS cables as there is apparently some way to wire them to get a partial benefit when connecting unbalanced gear to balanced mixers).

Huh, on a whim I tried making a cable where I modified the synth end so the sleeve wire is also connected to the jack sleeve and there's no more hum. But I don't see this method anywhere in the Rane Note 110.

So it's like this:

Synth end
- plug tip to tip wire
- plug ring to nothing (if using TRS plug)
- plug sleeve to ring wire AND sleeve wire

Mixer end is normal: t/t, r/r, s/s

Though I have no idea what, if anything this config is doing as far as any shielding / noise cancellation benefit. I can't tell a difference when I compare it to a TS-TS cable and turn the input and output to max on the mixer. Seems like the noise floor is the same (very very low).

I'm just going to go with this solution I posted above that seems to work fine unless someone wants to chime in with a better way. It's kinda crazy how difficult it is to find good (correct) info about how to connect (i.e. wire a cable for) an unbalanced instrument to a balanced mixer using 2-core cable.

Many people say they use regular TRS cables for everything, balanced or unbalanced, and it's fine. But this is not true unless you don't care about a 6-10dB drop when you connect an unbalanced instrument. And I suspect there's also some degradation in audio quality even if you boost the signal back to normal levels.

Other people say to use the Rane Note 110 connection type 14, but I have tried this method with 2 different cables using high quality Canare components, and if you leave the shield disconnected at the instrument end you get terrible hum that's audible at normal volume levels. I've verified the connections with my multimeter and it's exactly as specified for type 14. This method just sucks.

So it appears that you must connect the shield and ring (V-) wires to the shield on the plug at the instrument end, and leave the plug ring disconnected (mixer end is normal TRS config). This is the only way I'm able to get a connection that's at least equivalent to TS-TS, but using TRS-TRS plugs and 2-core cable other than the obvious method of dropping the V- wire and R connections on both ends and using only TS.

Unbalanced Instrument End:

Plug Tip to cable V+
Plug Ring disconnected (if using a TRS plug)
Plug Shield to cable V- AND Shield

Balanced Mixer End:

Standard TRS config
Plug Tip to cable V+
Plug Ring to cable V-
Plug Shield to cable Shield

Are you sure what ever synth you're talking about, isn't an TRS stereo out? stereo unbalanced signal into a balanced input will cause output issues and make the output weak. How long are your cable runs. Plug some phones into that output, you'll be able to tell if its stereo, unless its labeled mono.

Also, no the same hand, if those TRS cables aren't more than 50ft , just unsolder the ring on both ends and tape or heat-shrink those wires to preserve the ends so if you want to reverse later, then solder an jumper from sleeve to ring, and you've TS cables. I think you mentioned, TS sounded OK, you just didn't have enough.

They're all definitely mono TS outputs. I've verified with my multimeter. The only exception is my Behringer Model D, which the tech specs say is unbalanced but it actually has a TRS jack inside and the RS are bridged (basically this makes it compatible with a standard TRS cable with no -6dB drop, and it's exactly what I ended up doing inside the cable plugs).

And you're right, since all my cable runs are < 10ft / 3m I'm probably not getting any benefit from using modified TRS plugs and 2-core cable with unbalanced outputs compared to dropping the Ring altogether and making them equivalent to TS-TS. At least I can't hear anything -- I suspect the low noise that I do hear is 100% from the devices themselves, and nothing that the cable is picking up.

I'm just trying to make the best of a bad situation after idiotically buying a few dozen of the Canare F16 TRS plugs and 30+ meters of the Star Quad... not cheap! because I initially thought that all studio equipment with 1/4 jacks would be balanced, when in reality it seems like 97% of synthesizers and drum machines ever made are unbalanced. I don't get it, since it seems like making them balanced would be cheap and easy with zero downside... but that's how it is.

I should also clarify, for future reference, regarding the Model D... all I did was stick a bare plug into the output jack and do a continuity test with my multimeter to find the RS is bridged. Then I took off the side panel and saw a TRS jack inside. I didn't actually inspect the circuit to see if the R on the jack is connected to anything else on the PCB, or if there's just a single trace bridging it to the S. I suspect it's just a bridge and nothing else, but don't take my word for it as 100% true.

You could put the multimeter on AC voltage and tell if rind is pushing a signal.

Odd that the Model D would have Stereo Headphone Output and Mono on the line out.

It's not Stereo, it's mono on both sides of the TRS signal because every headphone cable is TRS. If they put a TS headphone jack, you'd only get sound in one ear.

I was looking at the Moog, but then I figured it was an behringer, looking on another everyone was wondering about that TRS being mono unbalanced, same thing, makes no sense , but thats how it is. But the Moog model D is mono but allowed stereo phones, and the reissue has stereo outs.

Edit. I was mistaken on the reissue having stereo outs, got that from a search but that site was incorrect.

You arrived at the easiest, most practical way of solving the unbalanced source to balanced destination situation. Congratulations. Pat yourself on the back (but don't hurt yourself.)

NO, absolutely not. As you have observed, if the source end leaves the ring terminal floating in the air, then you will have a problem at the (blanced) destination end. The destination is expecting the signal to exist between the Tip and Ring terminals, but the Ring terminal at the source end is floating in the breeze. (Until you properly connected it to ground/sleeve).

Hmm, I'm still not sure this is exactly what I did, or we are using different terminology.

At the source (synth) end, there's only Tip and Sleeve coming out.

At the Cable Plug, I connected Plug Tip to Cable Tip and Plug Sleeve to Cable Ring + Cable Sleeve. The Ring terminal on the actual Synth-end Cable Plug isn't connected to anything, since there's no Ring spring inside the Synth Jack anyway.

Yet the infamous "Rand Note 110" connection Type 14 (unbalanced source to balanced input) says to leave the Cable Sleeve completely disconnected at the Synth (source) end, and to connect Plug Tip to Cable Tip, and Plug Sleeve to Cable Ring only. But as I noted, this results in a connection full of hum.

I'm still stumped. I don't know if my method, which seems fine, is actually any better than using regular TS-TS cables. Is there any noise reduction at all doing it like this if my cable runs are all less than 3 meters? I need a bunch of TRS - TRS connections for another MIDI project I'm doing, so I'm wondering if I should just switch all my instruments to TS-TS into the balanced patch bay, and re-use all my TRS plugs for the MIDI thing...

I've just read somewhere you cant really determine an output as balanced or unbalanced based on the multimeter. best to reference manufactures manual.

Hey there, thanks for sharing. Do you mind letting us know which synth you are referring to ?

I'm not talking about any particular synth when I say "synth end" -- I'm talking about the cable only (where the wires of the raw cable connect to the plug on the end of the cable).

Is there still no single, authoritative (i.e. correct), intelligible reference for how to hook up two 1/4" plugs, in all their (12, as I count them) possible configurations??

What the Rane Note doesn't seem to anticipate is a source with no chassis ground reference of its own. Equipment without an AC ground pin (Roland pianos frequently used a 2-pin IEC inlet), or powered by a wall wart, fall into this category. If you don't carry the ground through to the receiving device, you're asking for interference. It's usually a buzz, and changes depending on how the sending device is oriented and the nature of the interference. The same thing happens with a guitar or bass plugged into a direct box and nothing else (no amp). If you lift the ground, it's almost always noisier.

armandhammer's solution of connecting the ring and sleeve together at the sending (synth) end is probably the most technically correct approach. It supplies a ground reference to the synth, while still getting some benefit from the differential (balanced) input at the mixer end, and it doesn't have a 6 dB loss. Unfortunately now the cables have to be used in a certain direction to get this benefit, although if you hooked them up backwards, I bet it would still work, and you couldn't tell the difference.

If you really wanted to geek out, you could add a resistor equal to the synth's output impedance to the ring signal, at the synth end. That would impedance balance the output, giving you all the advantages of a balanced output except the extra 6 dB of voltage gain. But getting inside each synth to do the mods probably isn't worth the trouble for most people.

Geoff