Audio Routing Switcher-1x2

The RDL ST-RX2 is a 1×2 audio routing switcher for directing a line-level source to one of two destinations. Its stated feature set combines silent audio switching, balanced or unbalanced routing, and open-collector logic control. The unit operates with +4 dBu nominal audio and uses two LEDs to identify the active NORMAL or SELECT state.

Ideal Use Cases

The ST-RX2 is intended for signal paths that need controlled routing of a line-level source between two destinations. Its balanced or unbalanced capability accommodates either routing approach specified for the model, while open-collector logic makes it suitable for control systems that can provide the required ground trigger. Local NORMAL and SELECT indicators help operators verify the active state. Published fast and soft switching behavior provides two defined timing profiles for system integration.

Why Choose This Model

The ST-RX2 combines routing control with documented audio performance at a +4 dBu nominal level. ON gain is unity with a 600 Ω balanced input and output, while OFF attenuation is greater than 80 dB from 10 Hz to 20 kHz on either input. The specified headroom is greater than 18 dB above +4 dBu. THD+N is less than 0.05%, and noise below +4 dBu is less than -80 dB, with 85 dB listed as typical. CMRR is greater than 45 dB at 100 Hz on either port.

Installation and Integration

Input interfacing is specified at 20 kΩ balanced and +4 dBu nominal. The audio output is rated at +4 dBu nominal, 150 Ω balanced, and uses a terminal block. Control is handled through the TRIG terminal, which must be externally pulled to ground, with a control current of 0.5 mA. Power must be ground-referenced 24 Vdc at 40 mA. Recommended power supplies are the PS-24AS for the USA and PS-24AX for international use; the power supply is not included. The left LED identifies NORMAL, and the right LED identifies SELECT. The specified ambient operating range is 0°C to 55°C.

For logistics, the cardboard-box package measures 2 x 2 x 4 inches and has a shipping weight of 0.198 pounds. The listed WEEE weight is 0.145 pounds.

Performance Highlights

• Frequency response with a bridging load is 15 Hz to 20 kHz within ±0.5 dB.
• Frequency response with a 600 Ω load is 30 Hz to 20 kHz within ±0.5 dB.
• The balanced audio output provides +4 dBu nominal level with a 150 Ω output specification.
• Unity ON gain maintains the stated nominal signal level through a 600 Ω balanced input/output path.
• Greater than 80 dB OFF attenuation covers the full 10 Hz to 20 kHz stated range on either input.
• Silent switching and balanced or unbalanced routing address both switching behavior and wiring flexibility.

These specifications define the unit’s behavior across frequency response, gain, isolation, distortion, headroom, common-mode rejection, and noise rather than relying on a single overall performance figure.

What Makes It Different

The supplied data publishes separate fast and soft switching times, with values listed in that order. The NORMAL input requires 10 microseconds or 5 milliseconds to turn off and 15 microseconds or 70 milliseconds to turn on. The SELECT input requires 15 microseconds or 10 milliseconds to turn off and 20 microseconds or 35 milliseconds to turn on. These explicit timing values allow an integrator to account for each transition when coordinating external control logic. The combination of ground-triggered open-collector control, 0.5 mA control current, active-state LEDs, and silent audio switching gives the ST-RX2 a clearly documented control and monitoring scheme.

Final Assessment

The RDL ST-RX2 is a focused line-level routing solution for applications requiring 1×2 switching, balanced or unbalanced signal handling, and open-collector control. Its published specifications cover audio performance, switching timing, status indication, power, and operating temperature in practical detail. Key integration considerations are the ground-referenced 24 Vdc requirement, the externally grounded TRIG terminal, the +4 dBu nominal interface, and the separately purchased power supply.