Balanced signal to 3.5mm motherboard connection

Arthur Khanti

New member
Nov 10, 2020
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Hi everyone, i have a quiet bizarre issue with windows 10 apps. i have a mic pre amp which provides balance and unbalance output. So, its directly connected to the motherboard, xlr - 6.3mm - 3.5mm. The problem is, some win apps have issues with that balance signal. Windows sound checking shows a good signal level, but in some sort of apps its a really weak and scratchy. I noticed that if i put 0 volume on one channel, inside a windows sound settings, some apps starts to catch signal but others stop. Reaper works fine though. Btw sorry for my eanglish.
 

Art Welter

Senior
Jan 11, 2011
832
19
18
Florida
Arthur,

If your motherboard connection is not balenced, but is the typical Left and Right input, and the XLR to TRS (Tip Ring Sleeve) adapter connects pin 1 to Sleeve/Shield/-, pin 2 to Tip (Left), and Pin 3 to Ring (Right) the polarity is reversed between the Tip and Ring.
If the Tip feeds Right, and the Ring feeds Left, the two signals will cancel each other out when combined, just as a "balanced" signal cancels common mode noise. If only one channel is up, there is no "phase (polarity) reverse", so the signal may come through, but 3-6dB down from what it could be if properly terminated.

Proper termination to feed two channels fed by TRS would be an unbalanced parallel ("Y") cord from the mic pre amp.

Art
 
Last edited:

Arthur Khanti

New member
Nov 10, 2020
4
0
1
22
Russia
Arthur,

If your motherboard connection is not balenced, but is the typical Left and Right input, and the XLR to TRS (Tip Ring Sleeve) adapter connects pin 1 to Sleeve/Shield/-, pin 2 to Tip (Left), and Pin 3 to Ring (Right) the polarity is reversed between the Tip and Ring.
If the Tip feeds Right, and the Ring feeds Left, the two signals will cancel each other out when combined, just as a "balanced" signal cancels common mode noise. If only one channel is up, there is no "phase (polarity) reverse", so the signal may come through, but 3-6dB down from what it could be if properly terminated.

Proper termination to feed two channels fed by TRS would be an unbalanced parallel ("Y") cord from the mic pre amp.

Art
Yeah, heard about that. But problem is, that happens only in certain apps, while others works fine. But unbalanced output directly to 3.5 works fine in anything. I already do that on previous motherboard and that were working ok. there is some signal in those apps but its so little and scratchy.
 
In addition to what Art said about trying to use a straight through balanced line to a stereo 3.5mm input I'm going to say 75% of the standard 3.5mm inputs on a computer are for mic level inputs.
Hitting them with a line level signal could be the reason for the "scratchy" sound.
Do you have an option for mic or line level inputs on the computer sound set up menu?

What mic pre amp are you using? Does it have a USB output?
 

Arthur Khanti

New member
Nov 10, 2020
4
0
1
22
Russia
In addition to what Art said about trying to use a straight through balanced line to a stereo 3.5mm input I'm going to say 75% of the standard 3.5mm inputs on a computer are for mic level inputs.
Hitting them with a line level signal could be the reason for the "scratchy" sound.
Do you have an option for mic or line level inputs on the computer sound set up menu?

What mic pre amp are you using? Does it have a USB output?
i have a 3.5mm blue one, which should be a line input but it has same issue. i have SM pro audio TC01 (like very cheap pre amp) it has a balanced and unbalanced outputs only. i temporary fix the problem by using Voicemeeter Banana application which allows me to convert 2 channel input to 1 channel and it works fine in every other apps. So, i guess it is only solution for me