Digital Noise lo-fi on Headphone out

[Max_Jack]

Hello I write you used post to ask for advice,
I have noticed for some time that when I use the Preamp Mic channels with mic or instruments connected to Directbox , putting the headphones channel headphones internal 1 or 2 use of the akg I notice that the signal has a strange degradation of the signal as a digital noise, as when you can hear the digital rustle, like lo-fi effect, especially the tails of the sounds are clearly perceived with this digital rustle, what could it be? The preamps? The converters? From the NS10 monitors I don't feel any degradation, I would like to use it with headphones but the annoyance is noticeable.. do you have any ideas?? Thank you!!

[Phil.c]

I would do a ribbon connector clean before anything else, alsothe Data connectors and BFC re-seat.

[Max_Jack]

Ok I try to read the service manual and I try to understand it better then, I have never opened ..

Tnx