1 (edited by rbbrnck 2013-04-30 23:34:51)

Topic: Fireface UCX for AES/EBU applications

I'm having a hard time trying to decide between Fireface UCX and Fireface UFX to adopt for my typical application.

I need to drive a sound system via long AES/EBU cable runs (50 meters and longer) with 48kHz feeds of stereo and multitrack music program from a MacBook Pro Retina 15" laptop running Ableton Live 9.

As Daniel Fuchs already pointed out in a previous reply to my questions, Fireface UCX needs an ADI-4 DD in order to drive the long line with the proper transformer-balanced AES/EBU output at 110-Ohm.

In this respect, Fireface UFX already has onboard a proper, 110-Ohm AES/EBU output on XLR which would make it self-sufficient in itself, but in the typical setup of the frequent flyer with a single backpack system, UFX it is considerably bulkier than the  tandem UCX + ADI-4 DD, as two smaller units pack easier into different pockets.

Another potential benefit of the twin half-rack units, in purely speculative terms about troubleshooting at remote locations, is that one unit can fail, but two is very unlikely, and if the failure lies with power supply, two external units is better than an internal one.

DuREC is not a feature that my application will ever need, as I will hardly ever feel the limit of having only 2 mic inputs, and these two aspects clearly speak in favour of the UCX.

And, again in favour of the twin-units setup, while a single AES/EBU output is sufficient in almost all instances of my application, having 4 separate output from the ADI-4 DD might inspire or suggest new ways of handling my application that I never considered before.

If this makes the UCX quite a strong candidate for my choice (hence, why shall I bother asking for suggestions in this forum?), for lack of direct experience I'm concerned with the reliability of an optical ADAT connection used almost entirely open-air, in dusty, windy, sandy locations, with an extreme range of temperature and humidity.

As optical ADAT connector seems to be the only way into the ADI-4 DD from the Fireface UCX, I find it hard not to question the reliability of a tiny, notch-sized optical connector that was invented to hook your CD player to your home theater amplifier in your living room. Apart from asking the more experienced ones, I mean.

Apropos input, I've read the manual more than once looking for clues, but I couldn't find any reference to the possibility of feeding the SPDIF coax output of the UCX into the AES/EBU XLR input of the ADI-4 DD in order to get the AES/EBU output; with my limited knowledge, my poor reading of the ADI-4 DD block diagram seem to suggest that this functionality isn't provided.

Could anyone from RME Support, or any user more experienced than me, confirm that ADAT is the only way into my possible Fireface UCX / ADI-4 DD setup? Or will an SPDIF coax work too, fed via a simple cinch/XLR adapter described in the user manual, right into the AES/EBU XLR input, when the only outputs I need are AES/EBU again?

(on second thought: this would be called an AES/EBU to AES/EBU converter, and it seems not described in the manual if I'm not wrong).

Given all this, would a UFX win hands-down in terms of reliability and performance, and I shall just accept its bulkier size and its "black box" concept with internal power supply as the most acceptable compromise for my application?

I'm running out of time and I need to buy whatever solution in order to have it delivered within the deadline of my next event.
I'm aware my application isn't that widespread to count on a huge number of users' experiences, but thanks in advance anyway for any hint in solving this (I admit, possibly silly) dilemma.

Re: Fireface UCX for AES/EBU applications

Poor me, already above 30 views and not a reply or a hint...
C'mon, hasn't any of you bought either a UCX or a UFX just to find out that it wasn't exactly the right one for the task at hand?
And you replaced either of them two?
Share your experience with me, please.


Re: Fireface UCX for AES/EBU applications

I have both and use whatever fits best. cool

Matthias Carstens

Re: Fireface UCX for AES/EBU applications

MC wrote:

I have both and use whatever fits best. cool

...Well, in your case I'd say this was the easiest one among all choices.
Oh, and the wisest, too! :-)

Thanx for your answer, Mattias, and I mean it, seriously.
It tells more than what it seems, and considering the source...

I might as well start with buying one set, and update to the next as soon as the need arises.
I'll go for the packable kit right now.

Roger and out.

5 (edited by rbbrnck 2013-05-20 18:09:25)

Re: Fireface UCX for AES/EBU applications

I'll post here the results of my first field day with the UCX on the job.
If my experience remains within this Forum, at lease other users will benefit from it, too, in case of need. I don't believe I'm the only one on earth with an AES/EBU application to handle, and an RME FF-UCX at hand for that.

Via Ableton Live audio software, I've played my 48kHz .flac audio files onto my RME Fireface UCX, from which I've managed to feed a total of 8 daisy-chained d&b audiotechnik D12 amplifiers with my AES/EBU signal through 50 meters of Belden 1800B cable terminated with Neutrik XCC Series XLR connectors.

I have selected the "Professional" voltage level setting for the SPDIF coaxial output on the Fireface driver setup, and (since the SPDIF coaxial output has a nominal impedance of 75?), used a Neutrik NADITBNC-M 110? transformer fed from an RCA-to-BNC cable adapter with the correct Neutrik rearTWIST 75? connector.

Signal was perfectly delivered at receiver side for hours. Not a drop, not a twist, not a glitch.

Performance sound pressure level has been controlled via the Fireface UCX front-panel rotary encoder assigned to the SPDIF coax output (limitation in hand-luggage weight negated the use of ergonomically correct RME Advanced Remote Control)

Even at lower SPLs, I (or any of the other listeners present) could not hear any artefacts from the severe output level attenuation that's been occasionally run during our field test. Some music program ran as low as -30 dBFS straigth into the amps.

Another RME device is on its way to me, purchased in order to handle the long AES/EBU cable run without having to depend on the single SPDIF coax output of the Fireface UCX. I've ordered one RME ADI-4 DD converter that has four discrete AES/EBU outputs on D-Sub 25-pin connector (and one dubbed on XLR connector). The ADI-4 DD will be fed from the optical ADAT output of the Fireface

From the tests I ran in the past two days, though, I can't see any reason not to trust the SPDIF coax output of the Fireface UCX adapted through the Neutrik BNC-to-XLR, 75-to-100 Ohm adapter.
Next week I'm out again, I will try to double the cable run and see if 100 meter at 48kHz signal is still dependably attainable.