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