(Unofficial) RME UCX II Interface Review and Measurements

[AnalogSteph]

Oh, believe me i tried ... i've managed to get it down very low using a USB power split to external 5V and with normal headphones it is barely audible, but if i plug in something like an IEM i can still hear it and it is annoying when nothing is playing.
So stuck with balanced for the moment ... hopefully when i upgrade my rig and change video card and motherboard (its coming from coil whine from the GPU pcb) then yes, i would not need balanced ... until then....

There is something very much fishy about your setup. Please describe your complete audio chain from wall power outlet (is this earthed?) to headphone out, and consider having this discussion moved into a new thread.

I have never needed a balanced headphone output in my life. I have heard mains leakage in IEMs if plugged into something powered from a floating SMPS, but that was just hum with very little else. You rather seem to have a traditional ground loop issue (possibly PSRR issue), and there is no way a headphone as a (mostly) floating transducer could be involved with one... there has to be some other reason if balanced cabling helps.

 

[Noodles]

Wall to power strip -> PC -> Powered hub (worse without it) -> ifi defender with external 5v power (worse without it) -> SSL 2+
->Schiit jotunheim 2 (XLR)
->ifi ican (RCA)
->Topping A30 (XLR)
->Kanto Tuk (RCA)

On both balanced devices i can hear nothing.
On the connected RCA ican there is noise.
On the SSL2+ headphone out there is noise
On the Kanto Tuk there is noise

1. If i swap the RCA on the other two amps - there is noise.
2. If i remove the ifi defender, so only into powered hub - noise gets even more high pitched and varies -> with it it is kept in the lower registers and is lowered as a whole (not completely gone).
3. If i plug directly into the PC without the ifi defender -> noise is even louder than the above test.
With ifi defender directly to PC noise level is inbetween 2 and 3

Regarding the topping galvanic isolator - build quality is very good, but has the exact same effect as the ifi defender (by ear).
I might just throw away 400 euro and get an intona ... hopefully its better... maybe.

 

[Trell]

Wall to power strip -> PC -> Powered hub (worse without it) -> ifi defender with external 5v power (worse without it) -> SSL 2+
->Schiit jotunheim 2 (XLR)
->ifi ican (RCA)
->Topping A30 (XLR)
->Kanto Tuk (RCA)

On both balanced devices i can hear nothing.
On the connected RCA ican there is noise.
On the SSL2+ headphone out there is noise
On the Kanto Tuk there is noise

1. If i swap the RCA on the other two amps - there is noise.
2. If i remove the ifi defender, so only into powered hub - noise gets even more high pitched and varies -> with it it is kept in the lower registers and is lowered as a whole (not completely gone).
3. If i plug directly into the PC without the ifi defender -> noise is even louder than the above test.
With ifi defender directly to PC noise level is inbetween 2 and 3

Regarding the topping galvanic isolator - build quality is very good, but has the exact same effect as the ifi defender (by ear).
I might just throw away 400 euro and get an intona ... hopefully its better... maybe.

Careful as the iFi Defender can destroy the USB input port:

RME UCX USB Stopped Working (Page 1) — FireWire & USB series — RME User Forum

RME UCX USB Stopped Working (Page 1) — FireWire & USB series — RME User Forum —

forum.rme-audio.de

 

[Noodles]

Yep I’m aware, it’s because the usb negotiation cannot be completed - especially valid for usb 3… and the usb controller sends max voltage to the unit. Usually fries the protection unit if it’s not resilient enough.
But yeah I used it powered, always. I even tried battery power for it and there is still some noise even then, so leakage is probably in data lines as well.

 

[Trell]

I've had the UCX II since last October and it's a very nice audio interface for my home office use. With the onboard DSP I add a 300ms audio delay for audio to video meetings in Zoom or Microsoft Teams (fixes lip-synch) while at the same time I can listen to myself with head phones in real time. Very handy as I've a mirrorless digital camera connected to an HDMI-USB adapter and this adds a delay.

I use the UCX II with the RME ADI-2 DAC FS since I have it already but the UCX headphone out is quite powerful but no replacement for the ADI-2 as I like features like Loudness, tone controls and slow volume ramp-up when switching between headphones and monitors.

 

[Trell]

What objectivists really want from RME: Sorry, couldn't resist. And sorry for the awful photoshop. And make pretend the lower Pro is the DAC!

View attachment 154740

Your prayer is answered though you did not seem that impressed after all in that thread.

RME ADI-2/4 Pro SE

More power and 4.4 mm Pentacon, yay! https://www.gearnews.com/superbooth-2022-new-rme-adi-2-4-pro-se-dac-interface-spotted/

www.audiosciencereview.com

 

[Scoox]

Does anybody know the idle power consumption of the UCX II? RME quotes this parameterfor the UFX II/+(19W if it's idle why does it use so much power?) but not for the UCX II.

 

[audafreak]

Does anybody know the idle power consumption of the UCX II? RME quotes this parameterfor the UFX II/+(19W if it's idle why does it use so much power?) but not for the UCX II.

Switched off - 0.0 W 3.9 VA
Switched on - 10.6 W 19.3 VA

So not so much.

 

[Scoox]

Switched off - 0.0 W 3.9 VAower d
Switched on - 10.6 W 19.3 VA

Awesome thanks. Merely curious, are these actual measured values? One more thing, and pardon my ignorance, do 0.0 W and 10.6 W mean the actual power consumption of the UCX II (excluding power supply losses), and 3.9 VA and 19.3 VA the overall power consumption measured at the power supply input?

 

[audafreak]

I just measured it some minutes ago, both on power suply input, not the unit itself, of course.
0.0 W and 10.6 W is real power consumption - what you will pay.
The rest is consumption without using power factor which is usuall < 1. I cannot explain it in English, sorry.
https://en.wikipedia.org/wiki/Power_factor

 

[Trell]

I just measured it some minutes ago, both on power suply input, not the unit itself, of course.
0.0 W and 10.6 W is real power consumption - what you will pay.
The rest is consumption without using power factor which is usuall < 1. I cannot explain it in English, sorry.
https://en.wikipedia.org/wiki/Power_factor

This is inline with the specs for UCX II:

• Typical power consumption: 13 Watts
• Current at 12 Volt operating voltage: 910 mA (11 Watts)

I've the UCX II stacked on top of the ADI-2 DAC FS and it is warmer than the ADI-2 DAC. I did add some small aluminium feet to the UCX II to get a little better cooling as the original feet are tiny.

 

[audafreak]

Yes, I have exactly the same setup.

ADI2 DAC consumption:
off - 0.1 W 2.8 VA
on - 6.4 W 12,6 VA

So half of UCXII.

 

[Rja4000]

Headphones out
Distortion vs Power plot

(with the RME ADI-2 Pro fs R - unbalanced mode - for reference)

 

[Trell]

Headphones out
Distortion vs Power plot

(with the RME ADI-E Pro fs - unbalanced mode- for reference)

View attachment 219760

Do you plan to make the same measurements for 300 Ohm?

 

[Rja4000]

Yes

 

[Trell]

YesView attachment 219773

Thanks!

 

[Rja4000]

@Trell
Is the chart readable for you ?
Any comment ?

 

[Trell]

@Trell
Is the chart readable for you ?
Any comment ?

Both the charts are very readable. Yet again thank you for all the measurements you’ve posted in this thread: it’s very much appreciated.

For an audio interface UCX II drives my Beyerdynamics 250 Ohm headphones to an unhealthy loud volume with excellent sound quality, as your measurements shows.

Still wants the DSP features of my ADI-2 DAC, so I use both.

Edit: To clarify my comment that I use both. The UCX II is for mic duties and connected to my ADI-2 DAC using ADAT. I’ve tested the UCX II headphone output, of course, but the ADI-2 is used for my headphones and monitors. This all just works on Microsoft Windows for my usage.

If I wanted an all-in-one desktop solution the UCX II would be it.

 

[Rja4000]

Both the charts are very readable. Yet again thank you for all the measurements you’ve posted in this thread: it’s very much appreciated.

For an audio interface UCX II drives my Beyerdynamics 250 Ohm headphones to an unhealthy loud volume with excellent sound quality, as your measurements shows.

Still wants the DSP features of my ADI-2 DAC, so I use both.

Edit: To clarify my comment that I use both. The UCX II is for mic duties and connected to my ADI-2 DAC using ADAT. I’ve tested the UCX II headphone output, of course, but the ADI-2 is used for my headphones and monitors. This all just works on Microsoft Windows for my usage.

If I wanted an all-in-one desktop solution the UCX II would be it.

I use the UCX II as my daily "Zoom" setup for now. Use a DPA 4066 and Focal Elegia.
Some noise gate, compression, and, of course, headphones EQ.
For the fun of mixing my hobby with my daily job ;-)

This is an impressive interface.

 

[Trell]

I use the UCX II as my daily "Zoom" setup for now. Use a DPA 4066 and Focal Elegia.
Some noise gate, compression, and, of course, headphones EQ.
For the fun of mixing my hobby with my daily job ;-)

This is an impressive interface.

As for the DPA 4066, I'm a little tempted: How is the comfort when using headphones? Which XLR phantom power adaptor do you use? What do you think of the mic noise level in practical use?

I use the UCX II mostly for video calls when working from home with an Earthworks Audio SR314 condenser mic and Beyerdynamics DT1770 Pro (closed back).

Like you, noise gate, a little compression but also a delay for lip synch with my Fujifilm ILC camera as well as a low-cut. For the delay I use Echo with wet signal as input to video call program and dry sent to my ADI-2 DAC FS for monitoring (that also applies headphone EQ). The Echo delay is a little crude with steps of 10ms but works fine for my use case.

Compared to so many other audio interfaces seen here on ASR the built-in Echo delay for simple lip-synch in video calls is pretty unique but very useful. It's a little hackish but it works.