Proper integration of the Ahuja SSA-250M public address mixer amplifier requires careful attention to load matching, input termination, electrical power provisioning, and transducer selection. Built with a heavy-duty steel metal chassis measuring 450 mm (W) × 160 mm (H) × 340 mm (D) and weighing 16.0 kg, this unit is engineered for stable rack shelf or tabletop industrial deployment.
AC Mains and 24V DC Battery Supply Integration
The amplifier is designed to operate on a standard 220–240V AC 50/60Hz mains supply (nominal 240V), drawing between 460VA and 500VA under typical operational loads. Connect the grounded AC power cord to a regulated, surge-protected industrial outlet.
For mission-critical paging installations requiring uninterrupted power, the rear terminal block supports an external 24V DC battery supply (two 12V car batteries in series (they are not included)) consuming up to 6A. The amplifier includes an internal automatic transfer relay that provides instantaneous changeover to connected external 24V DC batteries (they are not included) during AC utility interruptions without dropping audio output or resetting input channels.
Speaker Output Wiring & Load Impedance Matching
The rear-panel barrier screw terminal strip supports both low-impedance direct connections and high-impedance constant-voltage distributed speaker networks. Total speaker load must never exceed the 250W RMS rated capacity.
- Low-Impedance Taps (4Ω and 8Ω): Connect conventional speaker cabinets directly across the COM (Common) terminal and either the 4Ω or 8Ω tap. Calculate total series/parallel network impedance prior to connection to ensure the net load matches the chosen terminal without falling below the minimum impedance rating.
- Distributed Line Taps (70V and 100V): For commercial or industrial multi-speaker distributed systems spanning long cable distances, connect line matching transformers across COM and either 70V or 100V. Sum the primary wattage taps of all connected speakers; the cumulative wattage must not exceed 250W RMS.
Box Speaker vs. Driver Unit Selector Calibration
The SSA-250M features a dedicated rear-panel selector switch labeled 'Box Speaker / Driver Unit'. Set this switch to match the connected transducer type:
- Driver Unit Mode: When powering horn reflex compression drivers, this setting automatically defeats low-frequency bass boost. This cuts out excessive sub-100Hz excursion and protects compression diaphragms against mechanical damage and voice coil burnout.
- Box Speaker Mode: Utilized for wide-range cabinet speakers, column arrays, and ceiling speakers, enabling full 50Hz to 15,000Hz (±3dB) bandwidth response and full ±6dB bass/treble tone control adjustment at 100Hz and 10kHz.
Input Channels & Booster Amplifier Chaining
Terminate up to six dynamic microphones via the 6.3mm phone jacks (0.65mV / 4.7kΩ sensitivity). Line-level devices (media players, tuners) connect to Aux 1 or Aux 2 (100mV / 470kΩ). An external audio console can be patched into the dedicated 1V / 50kΩ Line Input.
To expand system output for large facilities, link the rear 1V / 1kΩ Line Output or 200mV / 600Ω Preamp Output to the line inputs of up to four Ahuja BR-250M booster power amplifiers, constructing a combined 1250W mono public address distribution system. In case of unexpected short circuits or terminal bridging, the rear-panel resettable thermal/magnetic circuit breaker trips automatically and can be manually reset once the fault is cleared.
