ASA 204

Quad Active Audio Summing Amplifier with RCA Inputs
Key Features
  • Converts stereo audio to balanced or unbalanced mono audio
  • Stereo inputs on RCA connectors, mono output on captive screw connectors
  • ±6 dB output gain switch
  • Rack-mountable 1U, quarter rack width metal enclosure
The Extron ASA 204
Model Version Description Part #
ASA 204 RCA Input 60-552-30

The Extron ASA 204 is a high performance Audio Summing Amplifier that converts two-channel stereo audio signals to balanced or unbalanced mono audio signals. It is ideal for summing stereo signals for use in mono multi-speaker PA systems in churches, halls, arenas, stadiums, and other environments where stereo signals would result in cancellation.

The ASA 204 offers four independent, active audio summing amplifiers in a single enclosure. It converts stereo audio signals from four different sources to mono audio signals and includes switch-selectable gain to achieve different output gain levels. The ASA 204 accepts unbalanced stereo input signals on RCA connectors and provides balanced/unbalanced outputs on captive screw connectors. This high performance summing amplifier enables long cable runs and immunity from interference and noise normally associated with the use of unbalanced audio equipment in professional integration projects.

The ASA 204 is housed in a 1U, quarter rack width metal enclosure, is easy to install in small spaces, and is rack and under-desk mountable. It can also be mounted at the projector using the Extron series of PMK - Projector Mounting Kit products.


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ASA 204, ASA 304
   Gain Generally unity.  Actual gain depends on whether or not both inputs have signals and also on the output wiring and DIP switch settings.  See the table below.
   Frequency response 20 Hz to 20 kHz, ±0.05 dB
   THD + Noise 0.03% @ 1 kHz at nominal level
   S/N >90 dB (balanced) at rated maximum output
   CMRR >75 dB @ 20 Hz to 20 kHz
Audio input
   Number/signal type 
      ASA 204 4 stereo, unbalanced
      ASA 304 4 stereo, balanced/unbalanced
      ASA 204 4 pairs of female RCA (tip-ring)
      ASA 304 (4) 3.5 mm captive screw connectors, 5 pole
      ASA 204 >10k ohms unbalanced, DC coupled
      ASA 304 >17k ohms unbalanced, 23k ohms balanced, DC coupled
   Nominal level 
      ASA 204 -10 dBV (316 mV)
      ASA 304 +4 dBu (1.23 V)
   Maximum level +20 dBu (7.75 V), (balanced or unbalanced), at 1% THD+N
    NOTE     0 dBu = 0.775 Vrms, 0 dBV = 1 Vrms, 0 dBV ≈ 2 dBu
Audio output
   Number/signal type 4 mono, balanced/unbalanced
   Connectors (2) 3.5 mm captive screw connectors, 5 pole (double stacked)
   Impedance <50 ohms unbalanced, 100 ohms balanced
   Nominal level 
      ASA 204 -10 dBV (316 mV)
      ASA 304 +4 dBu (1.23 V)
   Maximum level (Hi-Z) 
      ASA 204, ASA 304 only >+23 dBu, balanced; or >+17 dBu, unbalanced at 1% THD+N
   Power supply External
Input: 100-240 VAC, 50-60 Hz
Output: 12 VDC, 0.5 A, 6 watts
   Power input requirements 12 VDC, 0.2 A
   Temperature/humidity Storage: -40 to +158 °F (-40 to +70 °C) / 10% to 90%, noncondensing
Operating: +32 to +122 °F (0 to +50 °C) / 10% to 90%, noncondensing
   Cooling Convection, no vents
      Rack mount Yes, with optional 1U rack shelf
      Furniture mount Yes, with optional mini under desk mounting kit
      Pole mount Yes, with optional mini projector mounting kit
   Enclosure type Metal
   Enclosure dimensions 1.7" H x 4.3" W x 3.0" D (1U high, quarter rack wide)
(4.3 cm H x 10.9 cm W x 7.6 cm D)
(Depth excludes connectors.)
   Product weight 0.5 lbs (0.3 kg)
   Regulatory compliance CE, C-tick, c-UL, UL, FCC Class A, ICES, VCCI
   Product warranty 3 years parts and labor
   Everlast power supply warranty 7 years parts and labor
    NOTE     All nominal levels are at ±10%.
    NOTE     Specifications are subject to change without notice.
Shipping Dimensions and Weights
    Part # Height Width Depth Weight
    60-552-30 2.44" (6.2 cm) 7.13" (18.1 cm) 9.5" (24.1 cm) 1.73 lbs (0.79 kg)


Application Diagram

Panel Drawing

Panel Drawing
© 2021 Extron. Specifications are subject to change without notice.