SoundTube MA501t 50W Mono Low‑Voltage Amplifier

The MA501t is a compact 50W mono amplifier engineered for distributed sound systems at 25 V, 70.7 V or 100 V. Featuring both balanced (Euroblock) and unbalanced (RCA) inputs, automatic signal sensing or 12 V trigger power-on, and recessed gain control to prevent tampering. Ideal for small commercial installations with SoundTube or Rockustics speakers.

Despite its small footprint, the amplifier offers robust build quality in an extruded aluminum chassis, featuring onboard overload, short‑circuit, thermal, and peak clipping protection. A switchable 120 Hz high‑pass filter helps protect speakers from low-end overloads.

Compact mounting options include pole‑mounting, rack or chassis integration. UL60065, CE, RoHS and ETL certified.

Key Features

• Output Power: 50 W RMS at 25 V / 70.7 V / 100 V constant voltage systems
• Inputs: Balanced Euroblock and unbalanced RCA with input select switch
• Trigger Options: Signal‑sense auto‑on or 12 V trigger input
• Protection: Overload, short circuit, thermal, and peak output protection
• Gain Control: Recessed front‑panel gain adjustment
• High-Pass Filter: 120 Hz @ 12 dB/octave, switchable
• Enclosure: Rugged extruded aluminum
• MountingOptions: Pole, rack or chassis (optional rack plate AC‑SA502‑RMA available)
• Certifications: UL60065, ETL‑C/US, CE, RoHS, FCC

Technical Specifications

• Dimensions: 1.25″ × 3.9″ × 7.9″ (32 × 99.1 × 200.7 mm)
• Weight: 1.6 lb (0.73 kg)
• Shipping Weight: 3.2 lb (1.45 kg)
• Frequency Response (±3 dB): 30 Hz – 20 kHz @ 1 W, < 0.2% THD
• THD+N: < 0.1%; at-rated power < 0.5% THD
• Input Impedance: Unbalanced RCA: 20 kΩ; Balanced Euroblock: 15 kΩ
• SNR: >84 dB un-weighted
• Voltage Gain: 20 dB
• High-Pass Filter: 120 Hz @ 12 dB/octave (switchable)
• Trigger Input: 12 V DC signal-sensing or hard-wired
• Power Input: External 32 V DC power supply (included)

What’s Included

• MA501t amplifier unit (Black)
• External power supply
• 3‑pin and 4‑pin Euroblock connectors
• Mounting hardware