Audio Input Compatibility and Signal Routing
The Ahuja SSB-60EM public address mixer amplifier provides comprehensive input interfacing designed to accommodate dynamic acoustic transducers and standard line-level commercial audio sources. The input stage features four dedicated microphone input channels engineered for low-to-medium impedance dynamic microphones, presenting an input sensitivity of 0.65 mV across an input impedance of 4.7 kΩ via standard 6.35 mm (1/4") input jacks.
For auxiliary media and background music integration, the unit incorporates an auxiliary (Aux) channel with an input sensitivity of 100 mV and an input impedance of 470 kΩ. This input is fully compatible with line-level outputs from external audio mixers, media players, solid-state sound modules, and preamplifiers. Mic 4 and the Aux channel share an alternate volume control bus, allowing seamless selection between an additional speech transducer or line-level background music playback.
Speaker Impedance Matching and 100V Line Distribution
The output stage of the SSB-60EM features multi-tap terminal connections capable of driving both direct low-impedance loudspeaker configurations and high-voltage constant-voltage distributed speaker networks:
- Low-Impedance Speaker Taps (4Ω, 8Ω, and 16Ω): Engineered for direct connection to standard low-impedance voice coil loudspeakers, driver units, and low-loss monitor speaker lines without intermediary transformers.
- High-Impedance 100V Line Tap: Designed for driving multi-speaker commercial public address arrays over long cable runs. This output connects directly to 100V line-matching transformers (LMT) mounted on distributed ceiling speakers, column speakers, and industrial horn speakers.
- Impedance Loading Precaution: To prevent output transformer saturation and impedance mismatch, low-impedance (4Ω, 8Ω, 16Ω) loudspeaker loops and high-voltage 100V distribution lines must never be connected simultaneously.
Interconnection with Booster Amplifiers and Recording Equipment
For system expansions requiring total acoustic power beyond the native 60W RMS / 90W Max rating of the SSB-60EM, the chassis incorporates a dedicated preamplifier output. Rated at an output level of 200 mV with an output load impedance of 600 Ω, this line-level connection allows the mixed audio signal—shaped by the onboard cut-type bass (-10 dB at 100 Hz) and treble (-10 dB at 10 kHz) tone controls—to feed directly into external high-power booster amplifiers. Additionally, this output is fully compatible with external recording hardware and logging systems for real-time broadcast monitoring and documentation.
Power Source Compatibility and Emergency DC Changeover
The SSB-60EM offers dual-source power input compatibility for stationary facilities and vehicular installations:
- AC Mains Power: Operates natively on 220V to 240V AC at 50/60 Hz with a total rated power consumption of 160 VA.
- External 12V DC Supply: Equipped with heavy-duty DC barrier terminals supporting direct connection to an external 12V DC power source or 12V car battery (they are not included) drawing up to 3A at rated load.
- Automatic Failover: Features automatic changeover circuitry that instantaneously transfers power draw to the connected 12V DC battery source (they are not included) during AC mains outages, ensuring uninterrupted public address operation.
