• Registered: 2021-01-12
  • Posts: 4

Topic: Low output anomaly with UFX+ mic input 9

Hello,

I experienced a strange issue this morning with one of the onboard microphone inputs of my UFX+. I keep the same Audio Technica condenser mic plugged into that input every day for use with VOIP software such as Discord, Zoom, etc. The only change I ever make to it is turning off 48V phantom power before going to bed each night.

Today I powered on the unit, then my computer, and enabled 48V phantom power on mic input 9 within TotalMix FX. This time, for reasons unknown, even after turning on phantom power the output level was extremely low. Even tapping (gently) directly on the microphone grille only produced an output signal of around -50dB. At this point I turned off 48V, waited about one minute, then turned it back on. The mic input is now completely back to normal, with an expected output of around -12dB.

Any ideas as to what might have caused this anomaly? I just tested the other three mic inputs and they are all dead quiet and working normally. Could this mean that mic input 9 is dying or experiencing some type of rare failure mode?

Thanks in advance.

  • ramses
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  • Registered: 2012-10-14
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Re: Low output anomaly with UFX+ mic input 9

Can you please post a screenshot of the submix ?

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • Registered: 2021-01-12
  • Posts: 4

Re: Low output anomaly with UFX+ mic input 9

Sure, here you go.

https://i.imgur.com/ItHVKDW.png

  • ramses
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Re: Low output anomaly with UFX+ mic input 9

After 1st reading I misunderstood your posting and wanted to check the fader position of AN9 for the submix.
Now I got your point.
Sry, I have no idea why "power-cycling" of 48V resulted in getting the expected input level for your mic.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

5 Reply by NathanP (edited by NathanP 2021-01-13 19:51:59)

  • Registered: 2021-01-12
  • Posts: 4

Re: Low output anomaly with UFX+ mic input 9

The plot thickens! I have now discovered that this strange behavior is completely reproducible. It happens on any of the four onboard mic preamps; it doesn't matter which one I use.

Here are the steps I used. Following these steps in this order (at least for my unit) reproduces the issue 100% of the time.

1. Shut down my PC. Using the front panel controls on the UFX+, disable phantom power on the mic input currently being used.
2. Turn off the UFX+ and leave it off for 30 minutes or more.
3. After 30 minutes, turn on the unit. In its default state after powering on, phantom power is disabled on all mic inputs.
4. Turn on my PC, log in, and wait for TotalMix FX to initialize which enables phantom power on my mic input of choice (mic 9)
5. The issue now presents itself. Even with 48V phantom power enabled, the output of this condenser mic is extremely low.
6. Turning off phantom power, waiting a few seconds, and turning it back on does NOT guarantee that the issue is fixed. It appears that I have to wait at least 1 or 2 minutes (I'll time this with a stopwatch and report back) in order to have phantom power working correctly.

I should also mention that this issue occurs even when there is no computer involved. If I leave the unit off for 30+ minutes, then power it on and enable phantom power using the front panel controls, the mic output is STILL very low! My PC isn't even on in this scenario; the UFX+ is purely in standalone operation.

It appears that phantom power simply doesn't work for the first 1-2 minutes after the unit it powered on from an extended period of being off. Once this "warm up" period has passed, 48V works perfectly and never exhibits any strange behavior again.

Is it normal for phantom power to take a few minutes to become operational? I know most people run these units 24/7 so they probably never see this issue, but I'd still like to know what's going on here.

Thank you in advance for your time.

6 Reply by MC

  • MC
  • MC
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Re: Low output anomaly with UFX+ mic input 9

The +48V are separately generated within the UFX+. I expect a hardware defect in that circuit part in the unit.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2021-01-12
  • Posts: 4

Re: Low output anomaly with UFX+ mic input 9

Matthias,

Thank you for your reply. I too suspect that this is a hardware issue, because in the past 24 hours the problem has become worse. It now takes more than 10 minutes after powering on the unit for 48V to work. Even when it does, the noise floor of the mic preamps also rises from -85dB to -70dB for seemingly no reason.

I'll contact the dealer who sold me the unit to discuss warranty options. Thank you.

I would like to add that I LOVE my UFX+ in every other way, and I will absolutely remain an RME customer. This unit was a factory refurbished one, not a brand new one. That may have something to do with it.