PS Audio BHK Signature Preamplifier

Preamplifiers are at the heart of any high-performance music system. They are the critical controlling interface between our sources of music and our loudspeaker chain. Most preamplifiers do a fine job of control and isolation, but only a rare handful make magic happen. Add the BHK Signature Preamplifier into your system and suddenly you are enveloped in a wealth of musicality you’ve not yet experienced: deeper, wider, sound staging, improved separation of instruments and voices, subterranean bass, extended highs, and an openness you're unlikely to have experienced without this instrument in the system.

Design

The BHK Signature Preamplifier features two 12AU7 dual triode vacuum tubes in the input stage that act as a zero feedback balanced input amplification pair. A combination of an input stepped attenuator, built around the highest quality passive components for coarse volume adjustments, coupled with controlling the actual gain of the vacuum tube for finer steps, turned out to be the most sonically transparent level control we have yet heard. Finally, the output stage is a high-bias class A MOSFET design that is unaffected by cable and power amplifier interface challenges.

Application

Preamplifiers play a critical role in any separates audio system, strategically positioned between sources of music: CD players, phono preamps, DACs, tape recorders and tuners—and your power amplifier—the preamp serves essential roles of control and isolation. The BHK Signature Preamplifier features 5 identical balanced and single ended inputs, and converts all input signals into a balanced signal for the lowest possible distortion, and can be used in a two-channel audio system or as part of a home theater system. The high-bias Class A MOSFET output stage ensures unmatched performance with any cable and amplifier interface.

Technology

The BHK Signature Preamplifier is one of the most remarkable musical instruments in the world. It is the perfect interface between your sources and power amplifier. Designed by Bascom H. King, the BHK Signature distills Bascom’s 50 plus years of high-end audio design experience into a single masterpiece of audio amplification. “This is the best sounding preamplifier I have ever designed or heard,” and that’s saying a lot for a man of Bascom’s experience. Preamplifiers play a critical role in any separates audio system, strategically positioned between sources of music: CD players, phono preamps, DACs, tape recorders and tuners – and your power amplifier – the preamp serves essential roles of control and isolation. Control is simple in concept, but extraordinarily difficult to design in an acoustically transparent manner. Control duties such as input switching, volume, balance, and amplification can place unwanted acoustic thumbprints on the music if not designed with extraordinary care. The challenge in any design is to do as little damage to music’s purity as possible. What our Master Designer, BHK, has built will not only stand the test of time, but represents one of the finest musical instruments ever built to honor the music.

At the heart of any preamplifier are the gain stage that provides the amplification, and the volume control that manages how loud or soft the music plays. Inside the BHK Signature Preamp a pair of hand-selected and matched 12AU7 dual triode vacuum tubes provides the unit’s gain. Volume is controlled by a GainCell controling the actual gain of the vacuum tube. This offers the cleanest, lowest impact gain control in precise, half-dB steps. A massive, high-current transformer feeds the BHK Signature Preamp's power supply, which ensures that the unit can reproduce music with a wide dynamic range, without compression or distortion. Painstaking through-hole construction is used, along with the finest, hand-selected components: PRP resistors, high grade Audiophile capacitors---even the solder was auditioned for the best sound. Nothing was spared in the execution of Bascom King's design. Fully-balanced circuitry with a bandwidth that extends almost to DC on the low end and well above audibility on the high end are responsible for the effortless presentation of music BHK preamplifier owners enjoy. First time listeners remark at how much better-defined the space around instruments and vocals appears; the improvements in sound quality are nothing short of ground breaking. Openness, transparency, increased space around instruments---voices come alive in ways most never thought possible.

Bascom King has said, “vacuum tubes are simply more convincing and musically accurate than any other input configuration I have ever tried,” and the BHK Signature preamplifier proves his statement. All inputs, whether single-ended or balanced, are converted to a pure balanced signal by the dual triode vacuum tube for lowest distortion, highest linearity performance. Input switching is accomplished through hand-selected double-pole double-throw, gold plated relays that we’ve chosen for their sonic neutrality. The signals, once selected, are passed directly to the revolutionary new multi-stage attenuator controlling both volume and balance. High-performance analog audio products like the BHK Preamp benefit from the use of through-hole discrete parts in the signal path. Hand-selected through-hole PRP resistors, high grade Audiophile capacitors and the finest discrete parts are used throughout the BHK Signature preamplifier. Nothing was spared in its design. Even the solder we use has been auditioned for best sound. Extended signal bandwidth---from below 0.1 Hz to above 100 kHz--- is partly responsible for the effortless presentation of music produced by the BHK preamplifier. A massive power supply with an oversized toroidal transformer, the Class A MOSFET output circuit ensure that the BHK Preamplifier will effortlessly drive any cable or amplifier.

Features

ZERO-LOSS VACUUM TUBE INPUT STAGE

12V AND 6V TUBE SWITCH

COUPLED & BALANCED MOSFET OUTPUT STAGE

THROUGH-HOLE CONSTRUCTION

PRP RESISTORS IN SIGNAL PATH

5x RCA SINGLE ENDED INPUTS

5 XLR BALANCED INPUTS

SINGLE ENDED & BALANCED INPUTS

FULLY BALANCED INPUT TO OUTPUT

OVERSIZED POWER TRANSFORMER

BHK DESIGNED MOSFET VOLTAGE REGULATORS

BHK DESIGNED MOSFET HEADPHONE STAGE

REMOTE CONTROL

STANDBY BUTTON FOR VACUUM TUBE STAGE

-3dB > 200kHz

VOLUME & BALANCE THROUGH GAIN & ATTENUATION CONTROL

2x OUTPUT DC CONTROL TRIGGERS

EASY ACCESS TO TUBES FOR CUSTOMIZATION

EACH INPUT CAN BE SET TO HT BYPASS