PS Audio BHK Signature 300: Powerful mono power amplifier

The BHK Signature 300 Mono power amplifier delivers twice the output current of a stereo model and has half the output impedance. The BHK Signature delivers 300 W/ch into 8 ohms, 600 W/ch into 4 ohms, and 1000 W/ch into 2 ohms. But it is not only...

PS Audio BHK Signature 300
PS Audio BHK Signature 300

The BHK Signature 300 Mono power amplifier delivers twice the output current of a stereo model and has half the output impedance. The BHK Signature delivers 300 W/ch into 8 ohms, 600 W/ch into 4 ohms, and 1000 W/ch into 2 ohms. But it is not only capable of doubling the current, because… per channel it has twice as many internal components: lamps, power supplies, transistors, capacitors and resistors. The result is hard to put into words – the BHK Signature 300 easily delivers twice the clarity, openness and musicality of its stereo sibling.

PS Audio BHK Signature 300 is an amplifier created by experienced designer Bascom King, in which he embodied the hybrid amplification circuit he developed over 30 years ago and honed to the smallest detail. Naturally, the entire PS Audio development team, led by company chief Paul McGowan, participated in the creation of the terminal and its 2-channel brother.

PS Audio BHK Monoblock 300 1.jpg

The PS Audio BHK Signature 300’s input section is a zero-feedback/zero-loss balanced differential stage built around two carefully hand-selected Gold Lion 6922 tubes. This design provides excellent linearity while also preventing source noise and other distortion from creeping in. As a result, the detail, musicality and nuances of sound, the scale of the stage and the precise separation of instruments in space are preserved.

The balanced differential output stage of the PS Audio BHK Signature 300 is built on high-power N-channel MOSFETs, which provide less distortion compared to the P-channel version. Standard amplifier designs typically use complementary pnp-npn MOSFET pairs. PS Audio designers managed to avoid the problems of some sound degradation associated with such a topology, and obtain an accurately balanced output signal.

Each of the stages described above is powered by a separate analog block with a toroidal transformer. The circuits use separate discrete stabilizers based on MOS transistors, which reduce noise and help maintain detailed sound. The lamp section especially needs them. The model produces a power of 300 W (8 ohms) and 1 kW peak at a 2-ohm load. Such a monoblock can cope with any speaker.

PS Audio BHK Monoblock 300 2.jpg

Selected elements are used in circuit design, incl. PRP resistors, Rel Cap film and foil capacitors, etc. Surface mounting is not used. According to Bascom King, this technology worsens the sound.

The sides of the massive body of the PS Audio BHK Signature 300 act as heat sinks, and its top panel is covered with piano varnish. There is a removable cover on the back to access the lamps. There are also RCA, XLR and trigger input jacks. Toggle switch on The power supply is also located on the rear panel, and a button with a proprietary logo and indicator is built into the façade, which can activate the power supply or switch it to standby mode, which turns off the lamp unit. The PS Audio BHK Signature 300 is equipped with two pairs of custom gold-plated copper terminals for bi-wiring.

Specifications PS Audio BHK Signature 300

Output power 1 x 300 W (8 Ohm, 1 kHz, 1% THD), 1 x 600 W (4 Ohm, 1 kHz, 1% THD), 1 x 1000 W (2 Ohm, 1 kHz , 1% THD)
Frequency response 10 Hz – 20 kHz (+/- 0.1 dB, 2.8 V)
Frequency response 10 Hz – 200 kHz (+ 0.1 dB, – 3 dB)
Gain 30.5 dB (+/- 0.5 dB)
Sensitivity 1.3 V (at 250 W, 8 ohms)
Noise less than – 85 dBV (100 Hz – 20 kHz)
Input impedance 50 kOhm (RCA), 100 kOhm (XLR)
Output Impedance less than 0.1 ohms (50 Hz, 2.8 V)
Harmonic distortion less than 0.01% (1 kHz, 1 W, 8 ohms), less than 0.1% (20 Hz – 20 kHz, 1 W, 8 ohms ), less than 0.1% (1 kHz, 200 W/8 ohms, 400 W/4 ohms)
Inputs balanced XLR, unbalanced RCA
Other switching 3.5 mm trigger input Speaker
output 2 pairs of custom gold-plated screw terminals, terminals made from a single piece of purified copper with subsequent machine processing
Tubes in the input stage 2 double triodes Gold Lion 6922
Possibility of replacing tubes with other models is available
Power supply two separate isolated analog power supplies with toroidal transformers, respectively, for the tube and transistor stages
Power consumption 1600 W ( at 4 ohms); 850 W (at 8 Ohms), 175 W (idle), 75 W (in standby mode)
Dimensions (WxHxD) 434x221x356 mm (excluding connectors and terminals), 434x221x381 mm (including connectors and terminals)
Weight 37.7 kg

Francis Adamiak
Author: Francis Adamiak

Francis Adamiak is a passionate audiophile and expert in high-fidelity audio equipment, with a focus on amplifiers and speakers. Drawing on years of experience and a deep love for sound quality, he shares in-depth reviews and insights on the latest audio technology.