Power amplifiers stereo — Perreaux 100p

The Perreaux 100p is a stereo power amplifier sold under the Audiant name by Perreaux of New Zealand, built in a low chassis around MOSFET output transistors and a high-current power supply. It takes one input per channel, switchable between balanced XLR and unbalanced RCA, and a trigger input lets an upstream preamplifier or AV processor bring it out of standby automatically.

Key specs that matter

Measured with both channels driven at under 0.1 percent THD+N, the amplifier delivers 100 W rms per channel into 8 ohm and 145 W rms into 4 ohm. Distortion is quoted at 0.001 percent at 1 kHz into 8 ohm, the signal to noise ratio reaches 120 dB referenced to 100 W, and channel separation is better than 110 dB at the same level. Frequency response holds within 0.1 dB from 20 Hz to 20 kHz. The damping factor is 400 at 1 kHz into 8 ohm. Gain is 29.1 dB on the balanced input and 35.1 dB on the unbalanced one, with sensitivities of 1.0 V and 0.5 V rms and input impedances of 20 kohm and 47 kohm respectively. The case measures 431 mm wide, 286 mm deep and 67 mm high and weighs 12.0 kg.

Engineering and use context

Output transistors are Toshiba MOSFETs, and the supply uses shunt voltage regulators with extra filtering alongside audio-grade signal capacitors. A thermal protection circuit shuts the unit down if the MOSFET temperature passes 80 degrees C. Power draw is under 1 W in standby and 60 W at idle, climbing to 670 W at full output into 4 ohm. The trigger arrives on a mono 3.5 mm jack that treats 0 V as off and anything from 3 to 12 V DC as on. Mains fusing is a 6 A slow-blow type for 100 to 120 V supplies and 4 A for 220 to 240 V. Perreaux states that its published figures were taken after a ten-minute warm-up at 240 V on an Audio Precision ATS-2 analyser with a 65 kHz measurement bandwidth, so the numbers reflect a stabilised unit rather than a cold start.

Pairing

Feeding it from XLR engages the lower-gain balanced path, while a source feeding RCA benefits from the higher sensitivity of the unbalanced input. The slim case fits standard equipment racks, and the trigger input suits systems where a preamp or AV processor powers the whole chain. Loudspeakers of average efficiency in a room of around 20 m2 are well within its reach at normal levels.

Alternatives

The Perreaux 350 is a bigger stereo model in the Perreaux catalogue, delivering 350 W rms per channel into 8 ohm.