RDL ST-UMX3 – 3x1 Universal Mic/Line Audio Mixer is backordered and will ship as soon as it is back in stock.
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What is the RDL ST-UMX3?
The RDL ST-UMX3 is a three-channel STICK-ON audio mixer that combines mic-level or line-level signals into a single output. It adds inputs to an existing mixer or combines sources of different level, impedance or balanced configuration.
How does it work?

Each input has its own MIC/LINE switch, preamplifier and audio taper gain control, and a separate switch sets the output to mic or line level. The three preamp signals are actively summed and fed to an output amplifier with an RDL dual-LED VU meter for setting levels. Gain is adjustable from off to 60 dB on mic inputs and from off to 21 dB on line inputs. The mic inputs are not protected against phantom voltage, so RDL recommends the ST-MPA24 or ST-MPA48 phantom adapter when needed.
What are the key features?
- Three mic or line inputs — Each input switches between mic and line level with its own preamplifier.
- Mic or line output — A separate switch sets the output to mic or line level to suit the destination.
- LED VU output meter — A dual-LED meter with standard VU ballistics simplifies level setting.
- Independent gain controls — Audio taper controls set each input level from off to full gain.
- Low distortion — RDL specifies THD+N below 0.006% with 18 dB of headroom.
At Creation Networks, we do everything we can to create an excellent customer experience. This includes fast shipping and easy returns.
- Most in-stock orders placed Monday-Friday ship within 24-48 hours. General restrictions apply; please see our full shipping policy here.
- We offer a 30-day return policy from the delivery date on many products. Product restrictions apply. Restocking fees for the return of open-box items. Please see our full return policy here for more information.
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