The Emotiva BasX A3+ is a three-channel power amplifier from Emotiva's BasX series — a range of Class A/B amplifiers built around heavy-duty linear power supplies and designed to offer high-current amplification at an accessible price point. Within the BasX lineup, the A3+ sits between the two-channel A2+ and the four-channel A4, with higher-channel models extending to the A5, A6, and A7+. Above the BasX range sits Emotiva's XPA series, which delivers significantly higher power reserves for more demanding installations. The A3+ is purpose-built for powering a 3.1-channel system or for replacing the front left, centre, and right channels of an AV receiver's internal amplification with dedicated external amplification.
Amplification & Power Supply
The A3+ uses a Class A/B output stage fed by a heavy-duty linear power supply built around a large toroidal transformer. Each channel delivers 140 watts into 8 ohms or 200 watts into 4 ohms with all three channels driven simultaneously, ensuring consistent performance under demanding multi-channel loads. The amplifier achieves a signal-to-noise ratio of 112 dB (A-weighted) and total harmonic distortion plus noise of less than 0.02%. The damping factor exceeds 500 into an 8-ohm load. Power bandwidth extends from 20 Hz to 20 kHz within +/- 0.02 dB at rated power, while the broader frequency response reaches from 10 Hz to 80 kHz (+0 / -1.8 dB).
Connectivity
A key upgrade over the original BasX A3 is the addition of balanced XLR inputs on each channel, supplementing the existing unbalanced RCA connections. This allows the A3+ to be paired with processors and preamplifiers that offer balanced outputs, reducing susceptibility to noise over longer cable runs. Input impedance is 27 kilohms, with an input sensitivity of 1.25 volts for rated power into 8 ohms and a gain of 29 dB. Speaker connections use five-way binding posts that accept banana plugs, spade connectors, or bare wire.
Protection & Control
The A3+ incorporates comprehensive protection circuitry covering excessive operating temperature, shorted speaker connections, ground faults, and other common fault conditions. A 12-volt trigger input (accepting 5–12V AC or DC, drawing less than 10 mA) enables automatic power-on when connected to a processor or receiver, while the trigger output (12V DC, up to 120 mA) can cascade to additional components. The amplifier automatically detects and configures itself for either 115V or 230V mains supply at 50/60 Hz.
| Channels | 3 |
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| Amplifier Class | Class A/B |
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| Power Output (8 Ohms, All Channels Driven) | 140W per channel |
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| Power Output (4 Ohms, All Channels Driven) | 200W per channel |
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| THD+N | < 0.02% |
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| Signal-to-Noise Ratio | 112 dB (A-weighted) |
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| Damping Factor | > 500 (8-ohm load) |
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| Power Bandwidth | 20 Hz – 20 kHz (+/- 0.02 dB) |
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| Frequency Response | 10 Hz – 80 kHz (+0 / -1.8 dB) |
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| Input Sensitivity | 1.25V (rated power, 8-ohm load) |
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| Gain | 29 dB |
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| Input Impedance | 27 kilohms |
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| Inputs | 3 × RCA (unbalanced), 3 × XLR (balanced) |
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| Speaker Outputs | 5-way binding posts |
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| Trigger Input | 5 – 12V AC/DC; < 10 mA |
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| Trigger Output | 12V DC; up to 120 mA |
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| Mains Voltage | 115 / 230 VAC, 50/60 Hz (auto-sensing) |
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| Dimensions (W × H × D) | 432 × 102 × 394 mm (17 × 4 × 15.5"), excluding connectors |
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| Weight | 11.3 kg (25 lbs) |
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