BAlabo BC 1 MK-II Control Amplifier ($67,500) from Bridge Audio Laboratory is not know to many. Its more then worthy of the attention…
With supreme musicality and incomparable industrial design, the BAlabo BC-1 MK II Control amplifier presents a stunning new standard for extraordinary sonic performance and artistic revelation.
The BC-1 MK-II sports a wide array of radical new design concepts that together offer finely nuanced micro dynamics, three-dimensional soundstaging and a liquid midrange free of congestion, glare and artifact. An open and airy top octave suspends instruments in space and at minus 110 dB, background noise is essentially non-existent.
Improvement of Low Level Linearity by Post Attenuation Scheme
The BC-1 MK-II features a unique 'Post Attenuation' scheme that avoids signal degradation - line level signals are amplified immediately at the input stage prior to reaching the volume control. This method preserves the entire envelope of musical information including dynamic range and low-level linearity.
The BC-1 MK-II control amplifier features an extraordinary volume control of a high reliability and smooth action that consists of 8 circuits in 58 positions - accurate to 0.2 dB at every position. All resistors are custom made to BAlabo specifications and are of superior quality with signal contacts sealed to prevent dust intrusion. In addition, copper plates are installed between each section of the volume control for shielding and absorbing acoustical vibration. The switch is mounted to the chassis of with additional isolation materials to offer complete immunity from external vibration.
But there is much more to this volume control than amazing accuracy and purity of signal transmission. A massive 4" diameter gold plated indicator dial made of a high density alloy combines with the switch mechanism to offer an unsurpassed smooth action when advancing from one position to the next. The inner black finger-hold dial is cut with precision, indexed grooves around its circumference to offer a superb, positive tactile sensation. Attenuation settings are designed with a reverse-progressive rake so that course volume increments are at the 'bottom' of the dial and finer gradations are at the 'top'. There are 25 - 1dB steps in the middle of the volume control, and 10 - .5dB steps at the top of its range. In combination with the input attenuation found on the BAlabo BP- MK-II Power amplifier, the BC-1 MK-II's volume control can be 'positioned' to operate in the user's preferred range for the most desirable volume adjustment granularity. see settings.
Low Impedance Power Supply with 3D Construction
The BC-1 MK-II leverages the benefits of its three-dimensional structure to decrease effective power supply impedance. Specially designed capacitors are located in close proximity to the actual electrical load point in order to supply instantaneous power. Since it is designed compactly, the supply loop length is minimized for ultra-low impedance. The BC-1 MK-II can therefore realize superior impulse response and stability over an extremely wide frequency range.
Signal Ground Plane Connection Lug
Small differences in ground potential between components can detract dramatically from sound quality. The BC-1 MK-II offers a signal grounding lug (not chassis ground) to tie together the signal ground planes of the BAlabo Power amplifier to its own signal ground plane - thereby eliminating any minute differences in ground potential.
Precision Balanced Amplification
The BC-1 MK-II employs six blocks of amplifiers in each channel, in a perfect balanced circuit with high S/N and high input/low output impedance. Every BC-1 MK-II is carefully tuned at the factory with hand-matched feedback resistors, that perfectly reject common mode noise and drive THD to an absolute minimum
Noise Reduction for AC Line and Power Rectification
In home environments, electronic equipment like personal computers, add noise to the power mains and degrade the AC waveform - this can deteriorate the performance high quality audio components. The BC-1 MK-II employs a power line filter at the location of the AC inlet. The filter cuts the external noise and reshapes the AC wave form. The transformer of BC-1 MK-II has a very advanced shielding scheme to create a true ‘static shield’ by adapting an insulating copper foil between the primary and secondary windings – and the chassis – completely shielding the transformer and eliminating electromagnetic couplings.
Illuminated Standby/On Function
A Standby/On switch is located on the front panel so the BC-1 MK-II is ready at all times to provide the optimal sound quality without the need for a warm up period. Capacitors remain charged during standby. Main on/off is located on the rear of the chassis.
Remote Control Output Jacks - Standby/On for Amplifiers
A remote Standby/On scheme is employed in all BAlabo products. The BC-1 MK-II has a pair of RJ11 jacks on the rear panel for use with BAlabo power amplifiers, offering remote control power Standby/On switching for those units. This remote system is completely isolated from all audio signals.
Custom Components Throughout
For the ultimate in sound quality, components must be designed and selected through careful listening tests. The BC-1 MK-II boasts an amazing 85% custom components, such as all electrolytic capacitors in the power supply section, fixed resistors for the audio signal, copper foil capacitors for phase compensation and the relays. Audio improvements are easily recognized when compared to bulk style, off the shelf components.
Mechanical Grounding of Chassis
The four corners of the chassis are constructed with heavy-duty, extruded aluminum for superior mechanical integrity. The chassis is designed to aid in the dispersion of the resonant frequencies by the use of various materials (Aluminum/Steel/polymer) each with their own properties of absorption and transmission. External vibration is never propagated to the internals of the amplifier.
Signal Switching by Relay
For switching audio signals, relays are used to optimize the internal construction and improve operational feel. These relays are custom made and have gold plated contacts with a mirror surface finish to prevent signal degradation from oxidized or pitted surfaces.
PowerCon AC Inlet
The BC-1 MK-II uses a PowerCon connector for its AC mains inlet which offers superior reliability and product safety. The PowerCon has one-third the contact resistance of conventional IEC connectors and a larger maximum current rating (20A).
Integrated Spikes for Rigid Installation
The feet of the BC-1 MK-II are coated with Teflon with an under cushion material to prevent shipping damage. Once the BC-1 MK-II is installed, spikes (included) can be threaded into the base of each foot for additional mechanical grounding.
Weight – 57 lb.
16.75”w. x 17.5”d. x 7.5”h.
426mm w. x 465mm d. x 190mm h.
S/N – 110 dB
THD – .004%
Frequency response –
20Hz – 20KHz +0, -0.2 dB
5Hz – 100KHz +0, -1.0 dB
Power consumption –
48 Watts Continuous
8 Watts Standby
Connections and Controls
Inputs – 2 rca (bnc optional), 3 Balanced (XLR)
Tape loop – 1 pair in/out balanced (XLR)
Outputs – 1 pair rca (bnc optional), 1 pair balanced, switchable (either/or)
Volume Control – 58 discrete positions
Balance Control – 10 discrete positions via gold contact relays
AC inlet – PowerCon 20A (Power cord included for US operation)