Topic: Fireface UFX+ Mic preamp failure

Hi all,

I've had my UFX+ for 5 months or so. Yesterday I was on an orchestral session and one of the onboard mic pre's starting making a whining noise. It snuck in gradually, and then settled into a constant noise at around 10khz. I unplugged the mic cable from the preamp and the noise stayed. I can see the noise in totalmix on the input meter. Switching phantom on and off did affect the noise, but after a few seconds it'd settle back into the 10khz whine. Switching the channel to INST and back makes no difference.

At the end of the session I powered the UFX+ off, waited a few seconds and switched it back on. The noise was gone. I only listened for a minute or so - I suspect the noise will return. I'm back in the hall tomorrow to continue recording, so I'll have more time to investigate.

I imagine this is just a component failure, and I will be getting a replacement unit, but I just wondered what may have caused this? I was using the XLR patch lines in the concert hall, from the roof down to a backstage patch panel, and then into the recording room. There is doubtless a lot of cable involved here - probably upwards of 300 meters - and I was using 2x Sennheiser MKH800 twin microphones, which have a 5 pin XLR and share the ground pin.

I can't think of any reason such a setup would cause any issues, but I thought I'd see if anyone smarter than me has any thoughts?


Re: Fireface UFX+ Mic preamp failure

Sounds like self-oscillation due to high input capacity (very long cable runs). Shouldn't happen and can be fixed under warranty.

Matthias Carstens