Усилители мощности стерео — PS Audio PMG Signature S400

The PMG Signature S400 is a two-channel power amp assembled by hand at the PS Audio works in Boulder, Colorado. Darren Myers designed it and Bob Stadtherr handled the engineering, and it packs two complete PMG Signature amplifier channels into a single chassis. The PMG Signature series was created in 2025 to mark the 50th anniversary of the company, and the S400 was announced as shipping in July 2026 together with the smaller S200. The US list price is USD 9,999, and buyers pick a silver or a black front panel.

Key specs that matter

Rated output is 200 W per channel into 8 ohm and 400 W per channel into 4 ohm, measured at 1 kHz with under 1 percent THD. Frequency response runs from below 10 Hz to 80 kHz within 0.25 dB, while total bandwidth extends past 500 kHz and slew rate exceeds 200 V per microsecond. THD is typically below 0.002 percent from 20 Hz to 20 kHz at 1 W into 8 ohm. Gain is 26.2 dB, input impedance is 200 kohm balanced and 100 kohm single-ended, the damping factor is above 240 at 8 ohm between 20 Hz and 1 kHz, and crosstalk is better than 90 dB at 1 kHz.

Engineering and use context

The output stage starts in Class A bias before moving beyond it at higher levels. Negative feedback is kept very low, and in place of a conventional transformer-based supply the amplifier uses an active power supply architecture intended to deliver cleaner power with better current availability. PS Audio describes the internal layout and isolation of the two channels as arranged so that heavy demand on one channel only minutely disturbs the signal of the other. Power draw is under 2 W in standby, 190 W at idle and 390 W when delivering 50 W into 4 ohm. The mains input switches automatically between 120 V and 230 V at 50 or 60 Hz, and no fuse inside is meant for owner replacement. The chassis measures 406.4 x 444.5 x 203.2 mm including feet and binding posts, and weighs 25.9 kg.

Pairing

One balanced XLR pair plus one RCA pair accept a preamplifier of either output type. The four sets of silver-plated speaker terminals allow bi-wiring, and left and right subwoofer outputs let a powered subwoofer be connected directly. A 3.5 mm trigger input accepting 5 to 15 V DC and a 12 V trigger output let the amplifier power up together with other components in a custom installation or home theatre system.

Alternatives

The PS Audio PMG Signature S200 is the other stereo power amplifier in the same PMG Signature series.