Description
The STM-DA3 is a compact 1×3 microphone-level distribution amplifier designed for broadcast, studio and commercial sound installations. It accepts a balanced low-impedance microphone input and provides three electrically and acoustically isolated balanced outputs. The module preserves audio integrity while allowing a single mic feed to be distributed to multiple mic inputs without interaction.
Key features include a 1.2 kO balanced input, three isolated balanced outputs, and a 17 dB adjustable gain range via a 25-turn trimmer. The unit supplies 24 V phantom power to the input when the PHM terminal is used and provides near-total output isolation so loading one output does not alter the others. A Dual-LED VU meter gives immediate visual indication of operating level for quick setup.
Performance is engineered to studio standards with a frequency response of 30 Hz to 20 kHz ±0.2 dB, THD+N and IMD below 0.1%, and headroom greater than 20 dB under specified conditions. Noise performance is rated below 80 dB relative to specified reference levels and common-mode rejection exceeds 60 dB across the midband. Output isolation measures better than 135 dB balanced and 150 dB common mode, ensuring negligible crosstalk between outputs.
Connectivity is straightforward – one balanced microphone input and three balanced outputs with a PHM terminal for phantom power. The unit uses RDL’s compact STICK-ON form factor for unobtrusive placement and includes the Dual-LED VU adjacent to the terminal block for level monitoring. Power is supplied as a ground-referenced 24 Vdc source drawing approximately 40 mA.
Typical applications include broadcast splitting, recording feed distribution, house-of-worship setups, and distributed audio systems where multiple mic inputs must receive the same mic feed without interference. The STM-DA3 is suitable for dynamic and condenser microphones and integrates into existing mic-level routing schemes. Its electrical and audio isolation make it a reliable choice for mission-critical audio paths.
Installation and operation are simplified by the multi-turn gain trimmer and the integrated VU indication, enabling precise level matching to facility standards without external test gear. The module operates in ambient environments from 0 C to 55 C and ships in a compact cardboard package. Built on RDL’s low-noise preamplifier architecture, the STM-DA3 combines compact mounting, clear level control and professional audio quality.
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
