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DA 2x8SH Analog DA

Digital Distribution Amplifiers
Model DDA-1x8SH
Radio Systems, Inc.

Radio Systems’ DA-4x4b may be the best DA ever made. We've lowered the noise to a whisper at 102 dB below +4 dBm out with an internal toroidal transformer that dramatically reduces internal electrical interference fields. Distortion in the DA-4x4b is so low that it is hard to measure as a result of low noise op-amps and a careful design of the output amplifiers.

• Versatile configurations- quad, stereo or mono
• Front panel individual output level sets
• Internal torroidal transformer
• Super-low noise and distortion specifications
• Individual rear panel removable I/O barrier strip connectors
• 110/220 volt - CE certified
• Front panel audio presence and overload LED indicators
• Also available: DA-2x4b with stereo and mono configurations


DA-4x4b, DA-2x4b

4 inputs x 4 outputs (DA-4x4b)
2 inputs x 4 outputs (DA-2x4b)

Front Panel Indicators
Power, audio level illuminates at -24 dBm
(one per input channel), peak level illuminates at
+ 24 dBm (one per input channel)

Input Impedance: 40K ohms, balanced and bridging

Input Gain: 0 to +36 dB (16 dB, 26 dB, 36 dB
– jumper selectable)

Output Impedance: 60 ohms, balanced

Maximum Output Level: +25 dBm
(into 600 ohm load)

Frequency Response: +0/-.1 dB 20 Hz
to 20 kHz

Distortion: (thd + n): .002% 20 Hz to 20 kHz
(any output level into 600 ohm load)

Distortion: (SMPTE imd): .003%
(any output level into 600 ohm load)

Distortion: (dim) .002% (into 600 ohm load)

Noise: 102 dB below +4 dBm (full bandwidth into 600 ohm load)

Output Channel Isolation (crosstalk):
-105 dB (full bandwidth)

Dynamic Range: 123 dB

Headroom: 21 dB above +4 dBm output
(into 600 ohm load)

Common Mode Rejection: -50 dB (full bandwidth)

Dimensions: 19 inch (EIA rack mount) wide x 1.75 inches (1ru) high x 7.75 inches deep (with connectors)

Shipping Weight: 8 pounds

Who made my DA anyway? Over the 25 years that Radio Systems has manufactured these DA’s, there has been some “private labeling”.

If your DA says “Radio Systems” on the front, or “manufactured by Radio Systems” anywhere on the back - we made it. And regardless of when or whom you bought it from, we can service it or provide you any part you need. If your DA says “Audio-Metrics” or “Harris” on the front, we may have made it, as Radio Systems is one of several manufacturers who were contracted to make DA’s under these labels.

Again, check the rear panel to see if it has our name on the back, or call us and we’ll help you determine its “parentage”. Of course, the best way to get genuine Radio Systems is to specify a Radio Systems DA-4x4b.

”Audio-Metrics” and “Harris” are trademarks of Harris Corporation,
Mason, Ohio.

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Radio Systems, Inc.
Combining the best of two worlds - Radio Systems' famouse ultra low-noise and low-distortion Audio Distribution Amplifiers are now available with StudioHub+ connectivity.

StudioHub+ provides instant plug-and-play RJ-45 stereo connections to DA inputs and outputs, speeding initial installation and simplifying changes and troubleshooting. Wire all connections with CAT-5 twisted pair or use pre-made standard Ethernet-style patch cords for additional wiring efficiency.

All "SH" model products are circuit optimized for CAT-5 connectivity performance. This means that the inputs use instrumentation amplifiers, for ideal differential input balancing, ensuring the units excellent crosstalk specifications. Outputs utilize "electronic transformer" floating circuitry allowing traditional transformer style (one leg tied to the ground) wiring to unbalanced sources with maximum output levels unaffected.
  • Stereo / Eight Output Configuration
  • StudioHub+ RJ-45 rear panel connectivity
  • Front-Panel L/R level sets
  • Internal low-noise torroidal transformer
  • Front-Panel audio presence and overload LED indicators
  • 110/220 Volt internal voltage selectable
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Click here for detailed view
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Frequency Response
+0, -/1dB / 20Hz - 20kHz

Distortion THD+N
.002% / 20Hz - 20kHz, any output level from +4dBm to +24dBm (with 600 ohm load)

Distortion IMD SMPTE
.003% any output level from +4dBm to +24 dBm (with 600 ohm load)

Distortion DIM
.002% any output level from +4dBm to +24 dBm (with 600 ohm load)

-105dB / 20Hz - 20kHz

102dB below +4dBm output level unity gain measurement bandwidth 20Hz - 20kHz with 600 ohm input and output termination

21dB aboive +4dBm output (with 600 ohm load)

Dynamic Range


Inputs - 1 Stereo
Input Type
Instrumentation Amplifier

Maxium Input

LED Audio
-24dBm input level audio present trip point

Input Indicators
+24 dBm input level audio overload trip point

Outputs - 8 Stereo
Output Type
"Electronic Transformer" floating output

Maximum Output
+25dB over 20Hz-20kHz

Maximum Gain
Jumper selectable for: 16dB, 26dB, or 36dB

-50dB over 20Hz-20kHz

Output Impedence
60 ohms

19" wide x 1.75" (1 r.u.) high x 7" depth
48.3 wide x 4.4 (1 r.u.) high x 17.8 cm depth

8 lbs. / 3.6Kgs
23" x 13" x 3" / 58.5 x 33.7 x 7.7 cm

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Radio Systems, Inc. • 601 Heron Drive • Logan Township, NJ 08085 USA • Phone: 856-467-8000 • Fax: 856-467-3044