Used ARX MSX 4
Used ARX MSX 4 units offer a four-channel active microphone splitter in a single rack unit, delivering transparent signal buffering and routing with an ultra low noise design suited to demanding audio production environments. Second-hand ARX MSX 4 units bring professional-grade active splitting performance at a reduced cost. Browse the available used listings shown below to find the right unit.
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ARX MSX 4 specifications
| Brand | ARX |
| Segment | Audio |
About the ARX MSX 4
The ARX MSX 4 is a four-channel active microphone splitter housed in a 1U 19-inch rack unit. Each channel provides a four-way split with electronically balanced inputs and outputs at 50 ohms, with optional transformer-balanced front-panel splits at 600 ohms. Key features include a 'SilentStart' phantom power switch delivering +48VDC with a slow ramp on/off, a 20dB pad switch, headphone monitoring, and a through gain of 10dB adjustable internally. The unit achieves a signal-to-noise ratio of -104dB, distortion of 0.008 percent, and a frequency response of 10Hz to 20kHz within plus or minus 0.5dB. Power is supplied via an external MPS 1 dual power supply, which also includes a built-in headphone amplifier. Active splitting provides improved noise figures, increased RFI resistance and a consistent microphone load compared to passive alternatives.
ARX MSX 4 — buyer FAQs
What is the ARX MSX 4 and what does it do?
The ARX MSX 4 is a four-channel active microphone splitter in a single 1U rack unit. Each channel delivers a four-way split with electronically balanced inputs and outputs, giving a consistent microphone load and noise figures comparable to the best microphone inputs. Active splitting also provides increased resistance to RFI compared to passive alternatives, making the unit suited to complex audio production environments.
Who makes the ARX MSX 4 and where does it sit in the range?
The ARX MSX 4 is made by ARX. It sits within the brand's signal processing line as a rack-mount active splitting solution, and its power supply requirement is met by the companion MPS 1 unit, which also includes a built-in headphone amplifier, suggesting ARX built a complementary product family around it.
What are the key technical specifications of the ARX MSX 4?
The MSX 4 achieves a signal-to-noise ratio of -104dB at 10dB channel gain, distortion of 0.008 percent, and a frequency response of 10Hz to 20kHz within plus or minus 0.5dB. Through gain is 10dB, adjustable internally, and maximum output is +18dB. Output impedance on main, monitor and split outputs is 50 ohms electronically balanced, with an optional 600 ohm transformer on the front-panel splits.
What power supply does the ARX MSX 4 require?
The ARX MSX 4 requires an external MPS 1 power supply, which delivers plus and minus 25VDC along with +48VDC for phantom power. The unit connects via two male 6-pin XLR sockets. The MPS 1 also includes a built-in headphone amplifier. The MSX 4 does not operate from an internal or standard IEC mains supply, so confirming the MPS 1 is included is important when buying second-hand.
What should I check when buying a used ARX MSX 4?
Confirm that the external MPS 1 power supply is included, as the MSX 4 cannot operate without it. Check that the SilentStart phantom power, the 20dB pad switch, and the headphone monitoring function all work correctly on each channel. Verify the optional transformer-balanced front-panel splits are present if your setup needs them. Used units on 10K Used carry a 21-day warranty covering major functional faults; full details are in the buying guide at 10kused.com/used-av-equipment-guide/.
