Description
The ST-MA2 is a compact muting monitor amplifier designed to provide a simple local speaker drive solution while offering external control over output level. It supplies up to 2 Watts RMS peak output and accepts line-level inputs that may be wired balanced or unbalanced. The module is optimized for single-speaker monitoring in small AV installations and systems that require fast silent switching.
Key features include a presettable gain control, multiple control inputs for mute and selectable attenuation steps, and fast switching time under 50 microseconds. The ST-MA2 offers selectable attenuation steps of 3 dB or 6 dB via independent control inputs that activate when grounded. Muted attenuation exceeds 90 dB at 1 kHz for reliable silence when required.
Performance specifications support clear speech reproduction with a bandwidth of 45 Hz to 14 kHz and THD+N under 0.5 percent. Residual noise is specified below -80 dB at operating levels under 2 Watts RMS, and common-mode rejection exceeds 60 dB in the 50 Hz to 120 Hz band. Output impedance is nominally 8 Ω and the amplifier will drive 4 Ω loads when needed.
Connectivity includes a line-level input that may be wired balanced or unbalanced and control inputs for mute and attenuation that activate when tied to ground. The unit requires a ground-referenced 24 Vdc supply at approximately 200 mA for rated output and 220 mA at 2 Watts RMS. A front-panel or internal trimmer provides gain adjustment to match speaker sensitivity and room acoustics.
This monitor amplifier is commonly used to drive small tabletop or overhead speakers in conference rooms, boardrooms, courtrooms and public-panel forums. It integrates well into automatic mixing systems where externally actuated muting and attenuation improve intelligibility and prevent feedback. The compact form factor makes it suitable for discreet placements near the monitored speaker.
Installation is straightforward and requires basic audio wiring and a regulated 24 V DC source. The gain trimmer allows quick level setting during system commissioning and the fast, silent switching simplifies automated control logic. For tabletop installations the ST-MA2 can be paired with RDL mounting accessories for neat integration.
Overall, the ST-MA2 provides a small, controllable monitor amplifier solution with precise mute behavior and selectable attenuation steps. Its low noise and adequate bandwidth make it well suited to speech-centric monitoring applications. The module balances small size with useful control features for professional AV deployments.
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
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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
