PS Audio BHK Signature 300 Mono er et sæt forrygende musikalske hybrid-monoblokke med uanede kræfter, udviklet af berømte Bascom H. King med rør i indgangstrinnet og dobbeltsæt af MOSFET i udgangen.
The BHK Signature 250 and 300 power amplifiers are 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.
Available in both stereo and
mono models, the 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 stereo Signature 250 produces 250 watts/per channel into an
eight-Ohm loudspeaker, 500 watts/channel into four-Ohms, and stable into 2-Ohms;
enough power to satisfy even the hungriest of loads.
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 a clear step above
the stereo 250, on the order of 20% better, though both have the same character
of sound. Both the Stereo 250 and Mono 300 are one of the best performing,
musical sounding amplifiers ever made. Imagine your delight listening to either.
Zero-loss Input
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 input stage is a critical
interface
The connection between preamplifier and power amplifier is
critical, for it is at this junction where most essential musical details are
easily lost. Nothing in the design of a power amplifier is more important than
its input stage when preserving music’s finest nuances. In the BHK Signature a
vacuum tube serves as the perfect interface between the preamplifier and the
massive power output stage inside the BHK Signature. The input stage’s seemingly
impossible task of passing both delicate and powerful musical information
without loss is made possible by massive numbers of free flowing electrons
traveling within the BHK’s vacuum tube; electrons quantities that are not to be
found in transistors.
Used as the interface between the preamplifier and
the input stage of a power amplifier, tubes have no peer. Invented by Fleming in
1904, and refined by deForest in 1906, the vacuum tube is unique amongst
amplification devices: it boils an abundance of free electrons in empty space
while modern devices pull fixed numbers through solids. A tube’s high voltage,
empty space, rich numbers of electrons and connection through unattached fields
preserves details lost in the solidity of silicon. Tubes are the perfect
interface between sources and power stages.
The BHK Signature input
features a classic triode vacuum tube in a modern configuration. Hand matched
pairs of Russian Gold Lion 6922s are self-biased with constant current and high
voltage, free of timing and phase distortion without the use of negative
feedback. They provide the perfect interface between the delicate musical
transitions output by the DAC or preamplifier, and are electrically isolated
from the BHK power output stage which is connected to the loudspeaker.
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MOSFET Outputs
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 complementary design.
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Construction
Work on the BHK Signature began in 2014 with
the goal of building one of the top five power amplifiers in the world,
regardless of price. Bascom H. King took the charge under the condition he be
permitted to design and build the amplifier his way, without restriction and
that is what happened.
Starting with a clean slate, he reimagined the
traditional transistor and tube based amplifier as a hybrid, with vacuum tubes
on its input and transistors on its output, an idea invented by him thirty years
ago. In 1979 Bascom had designed the Infinity Class A, the world’s first hybrid
power amplifier, with tubes for inputs and transistors for outputs. Its success
was great and reviewer J. Gordon Holt, founder of Stereophile magazine wrote:
“it is the best sounding amplifier I have ever heard.”
To maximize the
benefits of the two amplification topologies inside the amplifier, it should be
built as if it were two separate systems, each with their own power supply
tailored to fit. Thus, the BHK Signature has two power transformers, one for the
vacuum tube input stage, the other for the MOSFET power output stage. Regulation
of the power supply for the input stage is important. Separate and discrete
MOSFET regulators are used throughout to preserve details found in the music and
keep noise levels to a minimum.
The path music takes through the
amplifier must be pure and without a polluting sonic signature. Each passive
component is hand selected to provide the cleanest path possible. PRP resistors,
film and foil Rel Caps, and the finest sounding parts possible are hand soldered
onto BHKs circuit boards. Bascom had insisted no surface mount parts be used in
the signal path.
No expense was spared on the BHK. Even the output
connectors are custom machined out of copper then polished and gold plated for
best connection.
The BHK Signature 250 stereo amplifier, and the BHK
Signature 300 Mono Amplifier embody one man’s life’s work and passion in the art
of amplification. That these monuments to music can be offered to music lovers
for less than $50,000 each is a testament to the years of experience invested in
their design; that they are significantly less than $10,000 is a miracle.
Kort beskrivelse | PS Audio BHK Signature 300 Mono er et sæt forrygende musikalske hybrid-monoblokke med uanede kræfter, udviklet af berømte Bascom H. King med rør i indgangstrinnet og dobbeltsæt af MOSFET i udgangen. |
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Vægt | 37.50 |
Dimensioner (HxBxD) | 22 x 43 x 36 cm pr. enhed |
Leveringstid | 2-3 uger |
Type | Monoblokke |
Frekvensområde | 10-20.000 Hz +/- 0,1 dB |
Ydelse | 300 watt v/8 ohm og 600 watt v/4 ohm |
Udgangsimpedans | 50 Hz |
Dæmpningsfaktor | >350 |
Input | RCA og XLR |