Description
The ST-UMX3 is a compact 3×1 universal audio mixer designed to combine three mic-level or line-level signals to a single output. It provides switch-selectable MIC/LINE settings on each input and a separate MIC/LINE switch for the output – enabling flexible level matching. The unit includes isolated input preamplifiers and individual gain controls for precise level setting.
Each input has a dedicated preamplifier with a single-turn audio taper gain control for smooth adjustment. Signals from the three preamps are actively summed and delivered to the output amplifier which includes an RDL dual-LED VU meter for visual level monitoring. The dual-LED meter follows standard VU ballistics and provides clear green/red indication from -11 dBu to +4 dBu.
Performance specifications include very low distortion and wide frequency response to preserve audio fidelity. THD+N is rated at < 0.006% and IMD is < 0.04% for mic gain and < 0.008% for line. Frequency response extends to 100 kHz with tight tolerances, and each channel offers substantial gain range and headroom for demanding signals.
The ST-UMX3 supports balanced and unbalanced connections and presents input impedances optimized for microphone and line sources. Input impedance is 600 Ohm for mic mode and 50 kOhm balanced in line mode, while outputs are 150 Ohm balanced and 75 Ohm unbalanced. Note that mic inputs are not protected against phantom voltage – RDL ST-MPA24 or ST-MPA48 adapters are recommended for phantom-powered microphones.
This mixer is suited to broadcast, installed audio, and production workflows where compact summing of discrete sources is required. It can be used to add additional mic or line inputs to an existing system, combine different level or impedance sources, or feed a single downstream processor or recorder. The combination of selectable input/output levels and low-noise preamps makes it appropriate for field racks and permanent installs alike.
Setup and operation are straightforward with front-panel gain controls and the integrated dual-LED VU meter for level setting. The unit requires a ground-referenced 24 Vdc supply at 55 mA and is specified to operate in typical ambient environments. Built for reliable operation, the ST-UMX3 provides clear level control, isolation, and visual metering in a compact package.
Free Ground Shipping
We offer free ground shipping on every purchase of $300 and more for US and US territory. Please choose "Free Ground Shipping (UPS/USPS)" option at checkout.
UPS Ground
UPS provides up-to-date tracking information. Ground service takes anywhere from 2-7 working days for delivery depending on destinations. UPS Ground does not deliver on Saturdays, Sundays or Holidays.
USPS Priority Mail/USPS Express Mail
For all shipments shipped via USPS, we offer 'DELIVERY CONFIRMATION' number with each package. Difference between tracking number provided by UPS vs USPS Delivery Confirmation number is: Delivery Confirmation status is updated when the delivery has been made or when the package has made it through major USPS stations.
Air Shipment
Air shipments, Overnight, 2nd day and 3 day select methods offer guaranteed delivery time for your shipment. If you are in hurry or in need for the items on schedule, select one of these methods. Up-to-date tracking information is provided with each Air Shipment. AVProSupply has the right to choose between Air shipments to meet or reduce delivery time. For guaranteed delivery of multiple items with expedited shipping, please contact our customer service representative for personalized assistance to get your items delivered to you when you need them.
International Customers
We offer shipping via USPS/UPS for our international customers. You can find different shipping options during checkout.
Most items ordered from AVProSupply will be shipped out from our California Warehouse. Will-Calls are only allowed with Appointment Only - Please call Customer Service to set one up between the hours of 9am to 6pm PST.
We Offer A 30-Day Money Back Guarantee:
Our main goal is to ensure your complete satisfaction with our service and products. If, for any reason, you are not 100% satisfied with your purchase, you can return it within 30 days of the purchase date for a full refund. Our 30-day money back guarantee applies to all of the products we sell, except for: TVs and monitors 20" and larger, Special Order merchandise, or any item indicated as non-returnable. Shipping is not refundable. Prior to returning your purchase, a Return Merchandise Authorization (RMA) number will be provided to you.
Refunds:
Refunds on returned items will be issued in the same payment form as received from the customer at the time of purchase. Once we receive the product and it passes inspection, we will credit your account. Please allow 3 - 6 business days for a credit to appear on your account.
Exchanges:
If the item was sent back to us for an exchange, please allow 3 - 5 business days for the replacement to be processed.
No Returns/Exchanges on the following:
- TVs and monitors 20" and larger
- Special Order merchandise
- Any item indicated on the website as non-returnable
For more information see our official Return Policy
