Hi Nauts. Hope you can help. I just wired up a patchbay, and I’m having a problem that’s driving me crazy. Everything works great except for the pairs that output to the preamps on my Fireface UFX. I’ve got line-level signals coming in to the PB from a couple synths, which are then output to the UFX preamps (which themselves take either mic or line signals). The PB connections are normalled.
The problem is that when I break the normal by plugging into the top jack, a low level of the signal is still getting sent to the interface ins. It’s fairly quiet, but it’s still audible. There’s also some crosstalk to the neighbor of the offending channel (also a UFX mic/line input).
Breaking the normal on the connections that go the the interface’s regular line ins works perfectly. It’s dead silent at the interface. I’ve also tried connecting different gear to the offending channels, with the same result - it’s only the UFX mic/line inputs, in combination with the patchbay, that are the problem.
Is this normal? I know that using the front inputs of the UFX for line signals is not the typical use-case, but it’s designed to handle that just fine. Why is this extra signal occurring, and what is the solution? I really don’t want to have to buy more line-level I/O, just to avoid the UFX mic/line inputs 
Is the channel gain set for line level for the pre-amp inputs in the TotalMix software? Is phantom power mistakenly enabled on those inputs?
My first few thoughts. I use a UCX with a patchbay and don’t have the same issues with the preamp ins.
I don’t know about the specifics of your setup or the crosstalk issue, but one possible culprit could be the interplay of balanced vs unbalanced vs impedance balanced inputs and outputs on the gear and patchbay and whether you’re using TRS or TS cabling. Check the manuals of your devices and the patchbay to see TRS vs TS compatibility.
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^This would be my guess too.
Phantom power not enabled, gains are set such that connected equipment RMS is between -18 and -12, peaks around -6 to -3.
All connected equipment is using balanced cables, as are the connections btw patchbay and interface. 
I took a peek at the manual for the UFX - it seems that the back TRS inputs are balanced and the front mic inputs are balanced, but the front 1/4" inputs are unbalanced. So that might be the culprit? It does describe them as “unbalanced TRS inputs” so I would guess it would work ok but it’s not.
Here’s a little excerpt from some website about going balanced outputs to unbalanced inputs (your situation):
“2) So your output device has balanced outputs and you are connecting to the input of another device with unbalanced inputs. Much of how to achieve this connection depends largely on the device’s output circuit design. Diving into the many different output circuit topologies would get a little too technical, and not the intended purpose of this article. In many cases, interconnecting a balanced output to an unbalanced input will work just fine - your signal will be unbalanced. However, with this method there are cases in which the user could experience high levels of (unwanted) distortion, and in the extreme cases, the output device could be damaged by plugging in a standard unbalanced cable. Simply said: Read the manual! Or call the manufacturer of the device and ask the people who made it! Or call us! Let us do the research for you.”
Good find, and thank you so much for your help! But- I just tried an unbalanced piece of gear and used only unbalanced cables through the entire chain and into the UFX front 1/4”s, and same problem 
I’m at a loss.
Problem solved! Using a TRS to XLR did the trick, no more ghost signals. So I think @MaxMyriad was pointing me in the right direction wrt the UFX mic/line inputs being TS. This is pretty confusing though- the specifications say the 1/4” input is TS unbalanced, but the rest of the manual says TRS balanced. The UFX even has leds on the front panel labeled TRS (which only turn OFF when an XLR is connected, strangely).
If the 1/4” mic/line is truly TS, I get why using the XLR instead, solved the problem. But what I still don’t understand is why connecting unbalanced gear to the 1/4” mic/line using an unbalanced cable didn’t work.
No complaints though. I’m just stoked that it’s fixed 
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Well done, glad you sorted it. Come to think of it I use xlr connections on my front inputs on my ucx, so no wonder I didn’t have the same issue.