Topic: Fireface UC and unbalanced instrument cables
Hi all,
Brand new owner of an FFUC here and loving it so far. Coming from a much cheaper interface, this piece of RME gear is amazing so far.
I have a question about the UC instrument inputs and using balanced vs unbalanced cables. I'm hoping someone can educate me so that I understand what's going on here (I'm not an expert at all yet).
In the manual, for inputs 1 and 2, it says:
"The two combo jacks also allow for the usage of mono and stereo TRS jacks."
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Does this mean that only balanced/TRS cables should be used with inputs 1 and 2?
At first, I was using an unbalanced cable with input 1 and 2 and I was hearing a really annoying high-pitched whine. I also tried inputs 3 and 4 with an unbalanced cable, and got the same high-pitched noise. I tried a few different unbalanced cables and a few different instruments (Minimoog Voyager, electric guitar, bass), and the noise remained. It was definitely more noticeable at higher gains levels -- i.e., more so with the guitars than the synth -- but it was there for all of the instrument/cable combinations. I did discover, for inputs 3 and 4, if I enabled "Pad" and "Inst", that seemed to get rid of the noise.
I finally decided to read a little in the manual, and I noticed the info about using balanced cables. In addition to what I quoted above, there was also this note for inputs 3 and 4:
"When using unbalanced cables with TRS jacks: be sure to connect the 'ring' contact of the TRS jack to ground. Otherwise noise may occur, caused by the unconnected negative input of the balanced input."
A few more questions:
What does it mean "be sure to connect the 'ring' contact of the TRS jack to ground"? I'm guessing I wasn't achieving that, which is why I was getting a high-pitched whiny noise.
Is the moral of the story here that I should be using balanced cables for all of my instrument/mic connections, inputs 1-4?
Thanks in advance for any help anyone can offer. Much appreciated!