UR242 Headphones output problem (unbalance and weak sound)

Hello everyone, I am experiencing problems with the headphone output of my UR242,

The output volume of the right channel is about 80% lower than the left channel. It also seems that there is a frequency filter, the sound in the right (in mono playback) is not exactly the same as the left one, sounds thinner and with no lower frequencies).

More info:
The headphone volume pot works nice and smooth with no “crackling” noises.
The input jack is inserted firmly with no gap, apparently ok.
The headphones sounds perfect plugged into the main output (1 - 2) at the rear. (Same issue occurs on other headphones that I have.)
The UR242 has been updated to the latest firmware version.
It happens on Mac and Windows,.
It happens with all sound software source (Playback of sounds, Cubase, Logic…etc…).
On playback, signal meters of dspMixFx are the same for R and L channels (only tested on windows because on mac the driver and mixer doesn’t work).

I have disassembled the unit to check the contacts, everything seems to be ok, I have applied some heat in case there is a cold solder, it has had no effect.

I am writing here because I am beginning to think that it may be a problem with the firmware or internal software of the interface.

Thank you in advance,

Hi Ivan
If your headphones have a mirophone, that could be the problem, so if you can, try with headphones that do not have a mirophone. It’s not really the headphones, but the trrs to trs adapters that sometimes mess things up.

Thank you for your tip, but I’m afraid thats not the problem.

My headphones (I have two or three models) are the typical recording and mixing pro studio ones with no mic. I tested with more than one of them…