Preamplifiers — PS Audio PMG Signature Preamplifier

The PMG Signature Preamplifier is a fully balanced analog line stage from PS Audio, designed by Darren Myers and sold in the US at USD 8,999. It belongs to the PMG Signature series and is built around a folded cascode topology with a Class A differential gain stage. The unit uses a double chassis construction, and no electrolytic capacitors appear in its power supply.

Key specs that matter

Connections comprise six line inputs, of which four use XLR sockets and two use RCA, plus a pair of balanced outputs and a pair of RCA outputs, two trigger sockets and a USB connector reserved for firmware loading. Maximum gain is 12.6 dB. Response is flat within 0.1 dB from 15 Hz to 150 kHz, and the -3 dB bandwidth runs from 5 Hz to 500 kHz. THD is below 0.0002% and THD plus noise below 0.0003% at 1 kHz with a 1 V input, while CCIF intermodulation distortion is 0.0005%. Crosstalk is -135 dB with one channel driven, and the noise floor is given as -145 dB. Input impedance is 50 kOhm on RCA and 100 kOhm on XLR, output impedance is 100 ohm, and the outputs reach 9 V on RCA or 18 V on XLR at 1% THD plus noise. The case measures 375 x 445 x 112 mm including feet and weighs 13.6 kg. Power draw is 18 W from an auto-switching 120 or 230 V supply.

Engineering and use context

PS Audio describes the gain circuit as fully complementary and direct-coupled, with servo control, and the output signal path contains no capacitors at all. Each output is driven by a Diamond buffer that runs without feedback, which keeps output impedance low enough to drive long interconnects. The power supply relies on film capacitors instead of electrolytic types. Level is set by a high-resolution stepped attenuator that moves in increments of one tenth of a decibel, fine enough for small changes at low listening levels.

Pairing

The line inputs cover a disc transport with DAC, a streamer, a phono stage and further sources, and the XLR inputs suit balanced components. The balanced and RCA outputs let one preamp feed a stereo power amplifier together with a powered subwoofer, or two separate amps when the speakers are bi-amped, while the high balanced output ceiling leaves room for power amplifiers with low input sensitivity. The trigger outputs can switch PS Audio amplifiers such as the BHK or Stellar models on together with the preamplifier.

Alternatives

The PS Audio BHK Signature Preamplifier is an earlier line stage from the brand, offered in the PMG Signature trade-up program with a higher credit than other models.