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124A
Audio Level Interface |
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The
Aphex Model 124A Audio Level Interface is designed to allow
use of -10dBV consumer hi-fi equipment with +4 or +8dBm professional
/ industrial / broadcast audio systems. It provides an extremely
clean, reliable two-way buffer so both systems can operate at
maximum performance levels, matching impedances and operating
levels.
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| Features |
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• Matches Consumer IHF equipment to Professional Equipment
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Dual Buffered Interface |
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Transformerless Outputs |
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Servo-Balanced Inputs and Outputs |
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Recessed Controls |
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Pushbutton 600 Ohm Input Termination |
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Clip Indicator |
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Self Powered |
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Superb Signal Quality |
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| Applications |
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Two-way
interface amplifier for connecting any unbalanced device
such as a cassette deck, equalizer, CD player or DAT deck to
the IHF inputs and outputs. The balanced inputs and outputs
go to a studio console, patchbay or other line level equipment.
The different gains and impedances are matched for optimal performance. |
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Line
driver. The servo-balanced input and output stages
of the 124 can be used as a very effective line driver for long
lines. The output stage provides a short-circuit proof, low
impedance source that will be relatively unaffected by the impedance
of the cable. Gain may even be taken to boost signal level.
In this application, either the unbalanced IHF or balanced high
level inputs may be used. For the latter, the IHF inputs and
outputs are simply jumpered. |
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Signal
splitter. The 124 may be used to provide two high quality
balanced outputs from a single unbalanced mono signal A"Y"
connector is used to split the incoming signal to each of the
IHF unbalanced inputs. |
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IHF
distribution amp. The very low output impedance of
the 124 allows it to drive a considerable number of unbalanced
devices such as cassette decks, VTR's, power amps, etc. Balanced
or unbalanced inputs can be selected by patching the various
inputs and outputs. |
| Performance |
| Aphex
products are well known for their audio performance. The 124
is no exception. Inputs and outputs are transformerless, for
wide, flat frequency response and perfect square waves to preserve
transients. Hum and noise rejection are very high while the
noise and distortion are almost non-existent. The 124 is so
clean it is a perfectly transparent interface for digital equipment. |
| Two-Way
Buffering |
The
124 is actively balanced and buffered in both directions, with
very low output impedances. A more expensive type of balanced
input circuit is used for even higher hum and noise rejection.
In addition, all inputs and outputs are carefully filtered for
freedom from RF interference.
Some other devices are passive in one direction, simply using
resistors to lower level from +4 to -10. The passive circuitry
unbalances the input, eliminates all common-mode rejection allowing
for hum and noise pickup, and presents a rather high impedance
at the -10 output, permitting even more noise to enter the system.
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| Servo-Balanced
High Level Circuits |
Although
more complex and costly, servo-balancing has many advantages
over conventional balanced circuits. On the inputs, it means
that high common mode voltages, such as induced hum from a nearby
AC line, are compensated for, preserving headroom that is sacrificed
in other devices (balanced input overload is greater than +30dBm
with common mode input voltage tolerance of over 200 volts rms).
The input impedance of 100K Ohms allows bridging over 600 Ohm
balanced or unbalanced line with negligible loading effects.
Front panel switchable 600 Ohm load allows for input line termination
when required.
On the outputs, servo-balancing means that the outputs may be
used balanced or unbalanced (single-ended) at any time by simply
grounding either unused pin. The servo compensates for the voltage
loss on one side so there is no 6dB loss of level as with other
systems. The outputs are also short-circuit proof, so nothing
is damaged if the wrong pins are grounded. Output impedance
is very low so long lines are driven effortlessly. A front panel
indicator will flash red when the balanced output level is 5dB
below clipping. |
| Compact
Package |
| The
124 is housed in an all metal package which is compact and self-powered.
It may be attached to its dedicated piece of equipment; rack
mounted singly or in pairs using the optional rack mounting
kit. |
| SPECIFICATIONS
- Aphex Model 124A Bidirectional Audio Level Interface |
| Audio |
| Bandwidth |
5Hz
- 100 kHz (+0, -0.5dB) |
| Dynamic
Range |
99
dB |
| THD |
0.005
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| Channel
Isolation |
>
70dB |
| CMRR
(typical) |
>
45 dB |
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Input |
| IHF
Input Connectors |
RCA
Jacks |
| IHF
Input Impedance |
18
k Ohms |
| IHF
Input Level |
-10
dBV; peak +15dBV (ref. 1V) |
| Balanced
Input Connectors |
XLR
3-pin Female |
| Balanced
Input Impedance |
100k
Ohms with front panel 600 ohm termination switch |
| Balanced
Input Level |
+4
dBm (+8dBm via internal jumpers); peak +30 dBm |
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Output |
| IHF
Output Connectors |
RCA
Jacks |
| IHF
Output Impedance |
150
Ohms |
| IHF
Output Level |
-10
dBV, peak +18dBV (ref. 1V) |
| Balanced
Output Connectors |
XLR
3-pin Male |
| Balanced
Output Impedance |
65
ohms |
| Balanced
Output Level |
+4dBm
Front panel adjustable ± 6dB, peak +25dBm |
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Other Specifications |
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Power Requirements |
100,
120, 220, OR 240 VAC, 50-60Hz |
| Dimensions |
1.75"H
x 8.25"W x 7.25" D (44.5mm x 209.5mm x 184.2mm)
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| Net
Weight |
3.5 lbs (1.6 kg) |
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There
are no downlaods available for this product at the moment.
But please
contact us should
you require further information.
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