Aphex Systems 228 Stereo System User Manual

• 8 Discrete -10dBV RCA Inputs
• 8 Discrete +4dBu XLR Outputs
• 8 Signal Presence/Clip Lights
• Extended Range VU Meter
• 8 Gain Trims
• Gold Plated Connectors
• Calibrated 11.78dB Gain
Exact -10dBV to +4dBu translation
• 12dB Attenuation Range
Great for unity gain applications
• Low Noise
• High Definition Audio
• Impedance Balanced Outputs
• High Reliability
• Calibration CD Included
• Front Panel Dimming
8-Channel Unidirectional Level Interface
Consumer Out to Pro In
w w w . a p h e x . c o m
Audio Quality
This is not just a buzzword at Aphex. Our
products are known around the world
for their ultra-high sound quality. It’s our
benchmark. Given that the Model 228 is
a relatively simple product, nothing more
than a level interface, we placed a high
priority on endowing it with the best sound
quality possible. That’s why we designed
it with high-voltage impedance-balanced
outputs and ground-loop isolating unbal-
anced inputs. The audio circuitry was care-
fully crafted throughout to maximize sonic
performance. There are no cookbook
audio circuits in the 228.
Aphex Leads The Way
There are plenty of stereo level interfaces
out there from various manufacturers. Of
these, the Aphex 124A enjoys a reputa-
tion as the one of the world’s finest. The
124 blazed a trail with it’s high definition
servo balanced input and output circuits
and remains as the premier bidirectional
stereo level interface. However, the need
for something else is becoming acute.
Today’s multichannel sound of 5, 6, 7 or
more channels makes using two channel
interfaces cumbersome and expensive.
Furthermore, the greatest need by far is
to translate consumer level outputs to
professional level inputs. Bidirectionality
is seldom needed. That’s why Aphex cre-
ated the Model 228 Unidirectional Level
Interface. It is perfectly suited to the vast
majority of multichannel uses in the studio
and the theater.
Unmatched Reliability
Aphex engineering and manufacturing pro-
duces products that last and last without
need for repairs or calibration. Some of our
products have literally been in 24-hour use
in the same rack for a decade or longer! When you
specify a Model 228, you know it will do its job flaw-
lessly and give you peace of mind.
Useful Extras
The 228 combines outstanding audio performance
with utility features that will make your installation and
operation much easier. The front-panel extended-
range VU meter lets you calibrate and monitor each
channel individually. Eight 2-color signal presence/
clip indicators let you know instantly if sound is pres-
ent on each channel and if overload occurs.
Front panel gain trims for all eight channels allow you
to balance the match gain. Fully clockwise, gain is
calibrated to the reference 11.78dB. Counterclock-
wise, the trimmer attenuates by 12dB, giving you
unity gain. For theater installations, a provision is
made to dim all the lights on the front panel.
A test CD with commonly used reference levels is
included for easily matching up your specific equip-
Level Translation: A Very Brief Tutorial
Mixing of consumer and professional grade audio
equipment is occurring more and more. For example,
consumer DVD players cost far less than pro ver-
sions, but don’t readily connect to the input of a
studio console or monitor system. Another example:
the high-end power amplifiers being used in home
theaters have balanced line level inputs and can’t
be driven directly from the consumer decoders and
preamps. In such cases, a multichannel consumer-
to-pro level interface is needed that can receive from
a consumer level RCA jack at -10dBV (316mV RMS)
and send to a pro level XLR jack at +4dBu (1.228V
RMS). That requires a voltage gain of 3.886, which
can also be stated as 11.79dB.
Typical Uses
Broadcast, Recording, Film, Home Theater, Installed
and Mobile Sound, DAW Input, Mastering.
228Audio Interface
PRO x8
Rated at nominal gain (11.78dB)
Inputs: 8 Unbalanced, RCA Female
Outputs: 8 Balanced, XLR 3-Pin Male
Gain Translation: 11.78dB Adjustable +/- 6dB
THD: Less than .005% at MOL
IMD: Less than .005% at MOL
Output Noise: -80dB @input shorted
SNR: 84dB
Dynamic Range: 104dB
Max Output Level (MOL): +24dBu, load > 600 ohms
Max Input Level (MIL): 3.55V RMS
Power Supply: Internal, fused
Power Requirements: 100/120/240V~ 50/60Hz
Size: 19 in. W x 1.75 in. H x 9 in. D
Net Weight: 5lbs.
Aphex Systems Ltd. • 11068 Randall St., Sun Valley, CA 91352. Tel: (818) 767-2929 Fax: (818) 767-2641 Email: sales@aphex.com . Aphex
and Compellor are registered trademarks.
Improving The Way The World Sounds
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