The human sense of hearing is surprisingly unimpressed by the perfect test results of customary measuring methods. This is why traditional transistor amplifiers come under fire again and again, although tube amplifiers are not real alternative as they have clearly audible characteristics.
Several innovations were needed to build an amplifier that does not impose its own sound on the music. These innovations go way beyond the standard circuits and may not be easily understood, even by technologists.
Combining the AMP CS2 with a B.M.C. Digital-to-Analog Converter (DAC) transforms it into a LEF stereo power amplifier that offers DIGM gain adjustment set by the DAC's volume control. In addition, B.M.C.'s balanced Current Injection (CI) input enhances the immediacy of reproduced music by processing the signal current of the source until it reaches the speaker's output voltage. B.M.C.'s LEF output stage avoids distortion before it occurs by relieving the sound-critical LEF single-ended Class-A transistor of all duties other than providing perfect signal reproduction.
Current Injection (CI), Discrete Intelligent Gain Management (DIGM), and Load-Effect Free (LEF) circuits are BMC's own, original designs. Used together and consistently executed, they lead listeners into a new world of tonal experience.
Low impedance current input lets the original current of a signal source flow through the amplifier circuit until the desired loudspeaker output voltage is attained.
Discrete Intelligent Gain Management
This is a volume and amplification control system that recalibrates gain without dividing and downgrading the input signal for a superior volume control.
Precise alignment of the amplifier to the desired volume occurs only on the level of the output voltage. This avoids unnecessary input signal attenuation, as well as excessive amplification.
Less amplification = less distortion and noise, which in turn = more natural musical quality.
Load Effect Free
The LEF technology handles a speaker's current demand separately from the voltage demand for superior speaker control.
The LEF output stage takes over the task of adapting the output voltage to the load (the loudspeaker). The signal transistor responsible for the sound is freed from driving the load to avoid distortions at the beginning. LEF makes it possible to use single-ended mode for high power, a mode that exceeds the classic Class-A by its natural lack of distortion.
Overall Negative Feedback is Obsolete
The B.M.C. amplifier's natural lack of distortion facilitates the intended renunciation of tonally suspect overall negative feedback.
The Current Injection input and Discrete Intelligent Gain Management would not be possible without the distortion-free LEF output stage and the absent negative feedback loop it induces.
Stabilized 2kW Power Supply
The power supply has nothing to do with the actual amplifier circuit, but determines the extent to which the potential of the amplifier really comes into effect.
A 2kW toroidal core transformer forms the solid basis for a very powerful, dynamic, and stable source of energy.
The storage in a whole battery of specially designed and produced Balanced Current capacitors is the basis for an exceptional musical evolvement and transparency.
An innovative electronic stabilization circuit especially for the power section filters mains voltage ripples and other disturbances out of the supply voltage, ensuring exceptional tranquility and dynamic stability.
All About the Music
The consequences of designing an amplifier for consistent, exceptional musical reproduction also lead to test results right out of the textbooks. But the essential thing is the musical experience. The expression "neutral amplifier" makes one think of an amplifier without a character of its own. But it's this lack of characteristics that makes describing the B.M.C. amplifier so difficult, since it can sometimes be brutally dynamic, sometimes highly expressive and full of detail, sometimes raw and discordant, sometimes bewitching and seductively beautiful, detailed and enveloped by its spatial presentation.
In the end, the result is a musical transparency that has never before been heard.
"More of the music and less of everything else," Mark Mickelson, Editor, The Audio Beat.
HiFi+ Review by Alan Sircom - Jan. 2015
The Audio Beat Review By: Marc Mickelson