Technology

Field Test: Universal Audio Model 2192

Universal Audio's Model 2192 Master Digital Audio Interface combines feature-rich design with impeccable audio quality.

Universal Audio's Model 2192 Master Digital Audio Interface combines
feature-rich design with impeccable audio quality. Priced at $2,795,
the 2192 offers two channels of AD/DA conversion, flexible routing and
a word clock generator/distributor. Universal Audio's traditional
commitment to audiophile analog sound is reflected in the analog signal
path, which features DC-coupled, fully dual-differential, matched-FET
and all-discrete Class-A circuitry. To avoid phase distortion and image
instability, no capacitors or DC servos are used in the signal
path.

The 2192's A/D conversion is always 24-bit with support for
44.1/48/88.2/96/176.4/192kHz sampling rates. Digital audio appears at
all outputs, with 176.4/192kHz audio carried on AES/EBU single- or
dual-wire (or ADAT optical with S-MUX interleaving). S/PDIF is fully
implemented, including 24-bit, 192 kHz. You can route signal straight
through the 2192 to monitor the signal at the inputs.

A RANGE OF CONVERSION CHOICES

Digital audio from any of the unit's inputs (AES/EBU, S/PDIF or ADAT
S-MUX) can be converted to analog. Clock source can be internal from a
digital audio source or from a separate external clock. A front panel
lamp indicates lock status. An internal clock conditioner keeps
external source jitter from affecting the internal clock. There are two
word clock inputs and four word clock outputs. The unit can also lock
to AES/EBU, S/PDIF or ADAT S-MUX, so the 2192 can serve as a handy
clock distributor for the small studio or mastering setup. It also
supports subclock and overclock, so, for example, you can use a 48k
clock while the unit is converting at 192 kHz.

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A Clock knob specifies the master clock source: Internal, Word 1,
Word 2, AES-S/PDIF and ADAT. Subclock (½x or ¼x) and
overclock (2x and 4x) synchronization are supported for converting at
submultiples and multiples of the sample rate. Super clock is not
supported.

The Sample Rate knob selects from 44.1/48/88.2/96/176.4/192 kHz.
Locked to external clock, the 2192 supports a ±12.5% varispeed
lock at all sample rates. The unit's sample rate is determined by the
clock and Sample Rate knob selections, except when the clock source is
set to AES-S/PDIF. In this case, the sample rate is automatically
detected and the sample rate knob has no effect. The 2192 does not
support sample rate conversion and won't sync unrelated clock rates;
for example, a 44.1kHz digital clock with 48kHz digital audio.

An Analog Output/DAC Source Select knob specifies the digital source
(AES-S/PDIF, ADAT or ADC) for the D/A converters and the analog outs.
The AES-S/PDIF setting is further controlled by the AES-S/PDIF switch
to the right of the knob. When ADAT In is selected, the ADAT optical
input is routed to the D/A converters and to the analog outputs; S-MUX
mode is determined by the sample rate knob. When ADC is selected, the
digitally converted signal at the analog inputs is routed to the D/A
converters and analog outputs for “true confidence”
monitoring.

The Single/Dual switch specifies whether AES/EBU single- or
dual-wire mode is used. For our needs, this switch is one of the 2192's
most attractive features. We often have to route audio to Pro Tools,
which uses dual-wire mode for 176.4 and 192 kHz. This switch does not
affect S/PDIF input, but in dual-wire mode, the S/PDIF output will
transmit the same signal as the AES/EBU “A” output.

The Digital Outputs Source Select knob specifies the signal that is
routed to the digital outputs, with the same selections as the Analog
Outputs DAC Source Select knob. The knob is generally left at ADC
except during transcoding, and any source that is selected is
automatically routed to all digital outputs simultaneously.

I/O ROUTING

The back panel AC input leads to an internal auto-sensing, filtered,
multistage power supply that supports 100 to 240 VAC and 50 to 60Hz
power. There are four transformer-coupled balanced XLRs for digital
I/Os. The left pair, AES “B,” handles one channel of I/O
when the 2192 is in dual-wire mode, and it replicates AES
“A” output in single-wire mode. (AES input B is used only
in dual-wire mode.) AES A handles up to 192kHz stereo I/O or one
channel of I/O when the unit is in dual-wire mode. Input bits (SCMS,
pre-emphasis, pro/consumer, etc.) are ignored. SCMS and pre-emphasis
bits are not set on output, but pro/consumer is set to
professional.

There are eight balanced connectors, including analog and AES/EBU
digital I/O, and they can individually isolate Pin 1 from ground via an
internal jumper block. The 2192 adheres to the universal Pin 2 Hot
standard.

Dual-stacked RCA connectors handle S/PDIF with unbalanced,
transformer-driven output and AC-coupled input. Input/output bitstreams
are set the same as AES/EBU. When the clock knob is set to AES-S/PDIF
and the digital outputs knob is not set to AES-S/PDIF, the S/PDIF
signal is used for clocking only.

Six BNC connectors handle word clock. The first four are 75-ohm,
5-volt CMOS drive outputs; the second two are AC-coupled, 75-ohm
inputs. Clock delay from input to output is 50 nanoseconds maximum and
is negative-edge-aligned when synchronized at a multiple or submultiple
rate.

ADAT optical I/O comprises two Toslink connectors with dual in-line
reinforced optical TX/RX. Channel usage varies from two for 44.1/48 kHz
to all eight for 176.4/192 kHz. Like S/PDIF, the ADAT input can be used
for clock only.

IN THE STUDIO WITH THE 2192

Connected to any piece of my digital gear, I was pleased when the
2192 accepted the signal and could route it elsewhere. The excellent
manual contains “recipes” for routing, as well as diagrams
for mastering and DAW setups, including Pro Tools|HD. I could use it
for dual-wire 192kHz projects with my Pro Tools Accel system and easily
switch it over to ADAT S-MUX or S/PDIF from my RME Hammerfall 9652
Nuendo system. I ran into S/PDIF failure with another converter when
routing it from the RME, so I was glad to see that the 2192 locked
immediately and performed flawlessly. As you can transfer audio between
AES/EBU, S/PDIF and ADAT-SMUX in real time, the 2192 is great for
transcoding.

The 2192 is hot — literally. In rackmount installs, leave
space above and below the unit. When stacked in open air and separated
by ½-inch spacers, the top was much cooler than when it simply
rested on a flat surface.

Ten-segment LEDs monitor stereo input and output. They are tied to
the converters, not the analog trims. The red clip segments are driven
by digital circuitry; the other nine segments are driven by analog
metering circuitry and calibrated to reflect digital signal. The unit
is factory calibrated at 0 dBFS = +22 dBu (and -18 dBFS = +4 dBu), but
this is adjustable using rear panel analog line trims next to each I/O
XLR. I've long been an advocate of adjustable trims for calibration.
It's a must for critical mastering situations and for times when
engineers need to have converters set at maximum sensitivity to capture
low-level detail in the analog source. Still, I wish the trims were
located on the front. For those who calibrate early and often (rather
than “set and forget”), it would make life easier.

I'll hate to send this box back to Universal Audio. We had some
great sessions with it. For recording a guitar directly into Pro Tools,
the 2192 mated wonderfully with my Millennia Origin STT-1. Jazz chords
were rich and creamy, while chicken pickin' chits were snappy without
being overbearing. All sample rates sounded great, but I found that the
more I use 192 kHz, the more that “something extra I can't
describe” hooks me into using loads and loads of disk space.

The crème de la crème example of the accuracy and
beauty of the 2192's conversion capabilities was when I used an AKG
C426B dual-capsule condenser mic in X-Y mode with figure-8s. I ran this
through John Hardy M-1 preamps. JamSync, which I co-own, has a room
upstairs for recording guitars and drums. It's moderately reflective
with plaster walls and various movable acoustic “room
shapers.” I tracked using my old Fender Princeton and favorite
hot-rodded Strat, experimenting with amp positions, as well as checking
the system with vocals. I also recorded some drum tracks with the mic
in various positions.

As I listened back, several things caught my ear: the clarity of the
instruments, the depth and breadth of space, and the richness of
detail. At 192 kHz, I was amazed at the results. You could practically
hear the ridges of the cymbal as the stick was slowly scraped along it
to produce a shimmer of sound — gorgeous. It was one of those
moments that reminded me of the reason I became an audio engineer: for
the sheer joy of being able to hear the stark beauty of sound.

Another telling moment came when my partner, Joel, walked in the
room and was shocked to find out that I wasn't playing, but listening
back.

Universal Audio enters the converter market with a clear-cut winner,
the Model 2192 Master Digital Audio Interface. The 2192 provides
routing flexibility with exquisite sound. Needless to say, I'd be very
happy if Universal Audio would bring out an 8-channel version of the
2192. Until then, we'll have to drive four of the units via word clock
for surround sound, a small sacrifice to make for achieving such
excellent results.

Universal Audio, 831/466-3737, www.uaudio.com.


K. K. Proffitt is the chief engineer at JamSync, a
Nashville-based studio specializing in surround sound
production.

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