Emotiva BasX A1 Monoblock Power Amplifier

The Emotiva BasX A1 is a single-channel monoblock power amplifier from Emotiva's BasX series — the value-oriented amplifier range that sits below the XPA Gen3 and XPA-DR Differential Reference lines in Emotiva's lineup. The BasX amplifier family spans from the A1 monoblock through to stereo and multi-channel configurations (A2, A3, A5, and A7), covering everything from two-channel hi-fi to full home theatre installations. The monoblock architecture of the A1 means each channel receives its own dedicated amplifier, power supply, and chassis — delivering complete channel separation and unrestricted access to the full power supply for a single driver or speaker system.

Amplifier Topology & Power Supply

The BasX A1 uses a Class A/B output stage driven by a heavy-duty linear power supply built around an oversized toroidal transformer. Linear power supplies are preferred in amplifier applications for their low electrical noise, while the toroidal transformer geometry reduces stray magnetic field radiation and improves efficiency compared to conventional EI-core designs. The A1 delivers 200W RMS into 8Ω continuously across the full 20Hz–20kHz audio band with less than 0.05% THD, and 325W RMS into 4Ω at 1kHz with less than 0.1% THD. Broadband frequency response extends from 5Hz to 80kHz (+0/−1.8dB).

Performance

The A1 achieves a signal-to-noise ratio greater than 112dB (A-weighted, referenced to rated power into 8Ω) and a damping factor exceeding 500 into an 8Ω load. Damping factor is a measure of the amplifier's output impedance relative to the speaker load: a high figure indicates the amplifier can tightly govern cone motion, counteracting back-EMF from the driver — a benefit particularly relevant for bass and subwoofer applications. THD+N is rated at less than 0.02% (A-weighted, referenced to rated power).

Connectivity & Control

Signal input is via a single unbalanced RCA connector with a 27kΩ input impedance and 29dB of gain. Input sensitivity is 1.6V for rated power into 8Ω. Speaker connections are via audiophile-grade five-way binding posts accepting banana plugs, spade lugs, or bare wire. A 12V trigger input (5–12V AC/DC, drawing less than 10mA) and matching 12V trigger output (up to 120mA) enable automated power sequencing with a preamplifier or AV processor.

Protection & Build

The BasX A1 incorporates microprocessor-controlled fault protection, monitoring for excessive operating temperature, shorted speaker connections, and ground faults. The mains input accepts 115V or 230V AC at 50/60Hz, with automatic voltage detection requiring no manual switching — making the unit suitable for use on the UK mains supply without modification.