I just got an RME Babyface Pro and I'll be coming out of a Focusrite ISA One mic pre which has an XLR out.
I'll be using the 1/4" inputs on the Babyface Pro which are TS inputs.
I'm trying to figure out if I should go with XLR to TS or if TRS would be fine as well.
 
Thank you!

Samuel540
I just got an RME Babyface Pro and I'll be coming out of a Focusrite ISA One mic pre which has an XLR out.
I'll be using the 1/4" inputs on the Babyface Pro which are TS inputs.
I'm trying to figure out if I should go with XLR to TS or if TRS would be fine as well.
 
Thank you!

The XLR Output of the Focusrite is a balanced output. It has three leads + - and shield. The TS input of on the Babyface in not balanced and uses two connections + and shield. 
 
The term "balanced" comes from connecting each wire to identical impedances at source and load. This means that much of the electromagnetic interference will induce an equal noise voltage in each wire. Since the amplifier at the far end measures the difference in voltage between the two signal lines, noise that is identical on both wires is rejected. The noise received in the second, inverted line is applied against the first, upright signal, and cancels it out when the two signals are subtracted. This also prevents noise and ground issues in the signal and allows to run much longer cables without problems.
 
If you use an XLR to TS adapter you are defeating the purpose of the balanced scheme, since the - signal will be shorted to ground.
 
Walt

WallyG

Samuel540
I just got an RME Babyface Pro and I'll be coming out of a Focusrite ISA One mic pre which has an XLR out.
I'll be using the 1/4" inputs on the Babyface Pro which are TS inputs.
I'm trying to figure out if I should go with XLR to TS or if TRS would be fine as well.
 
Thank you!

The XLR Output of the Focusrite is a balanced output. It has three leads + - and shield. The TS input of on the Babyface in not balanced and uses two connections + and shield. 
 
The term "balanced" comes from connecting each wire to identical impedances at source and load. This means that much of the electromagnetic interference will induce an equal noise voltage in each wire. Since the amplifier at the far end measures the difference in voltage between the two signal lines, noise that is identical on both wires is rejected. The noise received in the second, inverted line is applied against the first, upright signal, and cancels it out when the two signals are subtracted. This also prevents noise and ground issues in the signal and allows to run much longer cables without problems.
 
If you use an XLR to TS adapter you are defeating the purpose of the balanced scheme, since the - signal will be shorted to ground.
 
Walt

 
Thank you for that detailed answer, Walt.

I guess I'll be going with the XLR input instead.

To answer the original question though, and again stating what was mentioned in the other thread.  1) You should be using the 1/4" inputs of the Babyface from the preamp as they are a line level input and will not go through a secondary preamp stage, clean as it may be.  2) Balanced cables, with balanced input/output stages have noise rejection characteristics which help when the cable is either extremely long, or is picking up some other pesky interference.  It is usually not a problem with signals that have already been amplified, such as the output of a microphone preamp or speaker amplifier where the noise will not, in turn, be amplified further.  You can use a standard XLR to TRS cable, and the signal will come through fine, pin 3/ring will just go unused, not a big deal.  There is no real benefit to an XLR to TS cable.

I checked the documentation, and the inputs on that interface are balanced and expect a TRS plug. The multi-purpose input can be configured as balanced or unbalanced, but if you use it you'll likely want to set it to balanced. Either way, go XLR-to-TRS.

XLR-XLR is preferred, but if you go XLR-TRS be sure to be mindful of the adapter. Impedance matchers are not the greatest devices for audio quality.

bitflipper
I checked the documentation, and the inputs on that interface are balanced and expect a TRS plug. The multi-purpose input can be configured as balanced or unbalanced, but if you use it you'll likely want to set it to balanced. Either way, go XLR-to-TRS.

Actually, I think the 1/4" inputs on the side are unbalance.
 
You'll see it here:
https://www.rme-audio.de/...ducts/babyface_pro.php

mettelus
XLR-XLR is preferred, but if you go XLR-TRS be sure to be mindful of the adapter. Impedance matchers are not the greatest devices for audio quality.

Well, I hadn't plan on using any adapters... XLR to TRS cable.

rumleymusic
To answer the original question though, and again stating what was mentioned in the other thread.  1) You should be using the 1/4" inputs of the Babyface from the preamp as they are a line level input and will not go through a secondary preamp stage, clean as it may be.  2) Balanced cables, with balanced input/output stages have noise rejection characteristics which help when the cable is either extremely long, or is picking up some other pesky interference.  It is usually not a problem with signals that have already been amplified, such as the output of a microphone preamp or speaker amplifier where the noise will not, in turn, be amplified further.  You can use a standard XLR to TRS cable, and the signal will come through fine, pin 3/ring will just go unused, not a big deal.  There is no real benefit to an XLR to TS cable.

 
Thanks again, Daniel.
I haven't settled this issue, yet... I seem to be going back and forth. (Facepalm)

Obviously, you can try it and see. :-)

Sometimes, I come out of my RME quad Mic pre and into the quarter inch inputs on the front of my UCX. This gives me the auto gain control before the converters. It never occurred to me that they might not be balanced inputs.

Looks like they are not balanced so all this might apply to me too. Thanks for pointing it out. I can tell you I sometimes do it to record eight tracks without using the ADAT and sometimes just for the additional inputs with gain control.

When I'm playing too, it is nice to know gain is covered.