Power amplifiers stereo — Lyngdorf MXA-8400

The MXA-8400 is a power amplifier with eight channels, made by Lyngdorf Audio in Denmark, sold at USD 8,999 with a two-year parts and labour warranty. Rather than using the Equibit topology found in earlier Lyngdorf products, it is built around Purifi Eigentakt class D modules with EEC error correction, which Lyngdorf assembles in-house under licence. Each unit goes through a 24-hour test with every channel driven before it leaves the Danish factory.

Key specs that matter

In two-channel mode every channel delivers 200 W into 8 ohm and 400 W into 4 ohm, and at the rated distortion figure the 4 ohm output is given as 340 W. Bridging turns the unit into a four-channel amplifier delivering 800 W per channel into 8 ohm. Lyngdorf quotes THD of 0.001% at full power across 20 Hz to 20 kHz into both 8 and 4 ohm, falling to 0.0006% at 10 W into 4 ohm. Frequency response is flat within 0.1 dB from 20 Hz to 20 kHz, noise sits 128 dB below full output, A-weighted, in the low sensitivity mode, and the damping factor exceeds 1,200 into 8 ohm between 20 Hz and 1 kHz. Gain lies between 26.1 and 31.7 dB depending on mode. The chassis measures 450 x 145 x 348 mm and weighs about 10 kg.

Engineering and use context

The PowerPerfect supply feeds all eight channels with a combined capacity of 3.2 kW and includes mains noise filtering, and the amplifier runs without cooling fans. Peak output voltage is 58 V per channel, or 116 V when a pair is bridged. Adjacent channels work in pairs, and each of the four pairs can be bridged on its own with a slide switch, so one chassis can drive, for example, a bi-amped stereo pair plus a bridged centre or subwoofer feed. A 4-layer main board is laid out for signal purity and grounding. Input sensitivity is switchable between roughly 6 V and 2 V. Idle draw is 29 W, standby consumption stays below 0.5 W, and a Power State switch lets the unit wake from an external trigger or from a detected audio signal, shutting down after 15 minutes of silence.

Pairing

The eight inputs are balanced XLR only, with a 10 kohm impedance, so the MXA-8400 needs a balanced source ahead of it, such as a multichannel AV processor or a DSP crossover in an active system. Speaker connections are eight Neutrik speakON sockets rather than binding posts, which calls for speakON-terminated cables. Two 3.5 mm jacks handle trigger input and output, while an Ethernet port is reserved for servicing.

Alternatives

Where only two channels are needed, Lyngdorf makes the SDA-2400, a stereo power amplifier with digital inputs and the same per-channel power in stereo use.