The BHK Signature 300 power amplifier is the culmination of one man’s half-century search for perfection in music’s reproduction. Bascom H. King has designed amplifiers for many companies, some selling in excess of $100,000, including: Constellation Audio, Marantz, Infinity, and Conrad Johnson. This is the first amplifier Bascom felt was good enough to lend his name to. It is his finest achievement in a lifetime of work.
Tthe BHK Signature series is unparalleled in its ability to render details formerly lost in the music. The BHK Signature is a hybrid design enjoying performance benefits from multiple design techniques including, a balanced differential vacuum tube input, balanced differential MOSFET power outputs, and separate, isolated, analog power supplies feeding each.
When it comes to musically controlling and powering loudspeakers, the BHK Signature has no peer. The Mono Signature 300 doubles the output current with half the impedance of the stereo model. Each Mono Signature produces 300 watts into an eight-Ohm loudspeaker, 600 watts into four-Ohms, and 1000 watts into 2-Ohms. But more than just doubling the current, the BHK Signature 300 also doubles every internal component of the 250 into one: double tubes, double power supplies, transistors, capacitors and resistors. The results are hard to put into words. The BHK Signature 300 is easily twice as clear, twice as open, significantly more musical than its stereo counterpart. Imagine your delight listening to either.
- Zero-loss parallel vacuum tube input stage
- Fully paralleled inside (not like a traditional bridged approach)
- Differentially coupled, paralleled, balanced MOSFET output stage
- All through hole construction (no surface mount parts)
- RCA Single ended input
- XLR balanced input
- 300 watts 8Ω
- 600 watts 4Ω
- 1000 watts 2Ω
- Less than 0.1% thd 20Hz to 20kHz at rated power
- Damping factor 100 for excellent loudspeaker control
- Front panel standby button for vacuum tube input
- -3dB greater than 200kHz
- Dual, custom, solid copper, gold plated output binding posts
- Fully balanced from input to output
- 83 pounds
- Input 12 volt trigger
- Easy access for tubes
The power amplifier is technology always present in stereo systems. Yet, despite the fact everyone uses them, few appreciate the power amp’s critical role in preserving music’s nuanced details, because most amplifiers fail to preserve them. Overtones from plucked instruments, subtle cues defining placement, depth, soundstage width, and transient decays are often lost in the power amplifier.
The BHK Signature power amplifiers are unique in their ability to faithfully pass even the tiniest of details. The first listen to the BHK is like pulling a blanket off the loudspeakers. Suddenly revealed are the tiniest of details that now ring clear through the BHK, perfectly preserved through its extraordinary bandwidth, low feedback, vacuum tube and MOSFET design.
The hybrid approach used in the BHK Signature takes advantage of the best traits technology has to offer, unavailable in traditional solid state or tube designs. While vacuum tubes are the perfect input stage, they cannot make the same claim on a power amplifier’s output. Conversely, solid state designs are correct for output stages, but suffer when used as inputs. Only a hybrid approach takes advantage of the best in both disciplines.
A power amplifier connects its reservoir of energy to the loudspeaker through a type of valve (solid state or vacuum tube) controlled by the input stage. If the input stage has done a good job of preserving music’s subtle details, textures, timing and phase information, transferring it without loss to the power stage and eventually the loudspeakers is best handled by a tube-like solid state device known as a MOSFET.
MOSFETs handle power without the additional circuitry needed by tube power amplifiers, and they sound better than tubes or their solid state alternatives, bipolar transistors. Field effect transistors were first invented by Julius Edgar Lilienfeld in 1925 and because they require very little current and operate with an invisible field, their sound is more closely related to vacuum tubes than transistors, without suffering any of the issues driving loudspeakers typical of vacuum tube power amplifiers.
Not all MOSFETs are the same, their differences characterized by their relationship with the input signal and the power supply driving them: N-types for the positive going signals, P-types for negative. It turns out that N-types have lower distortion and perform better than P-types. Despite this anomaly most power amplifier designs use both types of transistor in a configuration known as complementary symmetry. The BHK takes a different approach, one that avoids the problem of uneven performance between N and P devices altogether. Using only N Channel MOSFETS in its output stage, the BHK Signature produces a near-perfect balanced waveform without the degradation inherent in a complimentary design.