BDCD1.1 Belt Drive CD Player / Transport
A CD transport with a belt drive is a truly uncommon concept.
The highest grade analog record players share both a belt drive and high inertia. And not without reason, for this is the only way to create a turntable with perfectly smooth rotation and tranquillity. A patented belt drive with high inertia, in the form of an acrylic-stabilizer, applies this principle to B.M.C.'s BDCD1.1 CD Belt Drive Player/Transport.
In addition to constant rotation, the stabilizer reduces vibrations of the CD. The result is an inner peace and authority unachievable by a lightweight, relatively nervous-sounding direct drive.
Belt Drive is More Than Just a Belt
1. Belt drive decouples the motor vibration from the CD
2. The CD turns on a precision bearing, analogue to a turntable bearing
3. A CD stabiliser removes vibrations and resonances from the CD
4. Due to the high inertia of the stabiliser any rotation is quiet and smooth.
5. Quiet operation of the servo circuit instead of plenty small and harsh speed changes.
According to this short description it should be understandable that mid and high frequency jitter won't ever happen.
The mechanical consistency of the BDCD1's music-optimized, belt-driven flywheel drive is reflected throughout the BDCD1 design.
Superlink, our uncompromising digital connection, employs four separate BNC cables to transmit to the B.M.C. DAC. This works out to one cable per clock and one for the digital audio signal, with the master clock very close to the digital/analog conversion.
The result: natural-sounding music.
An optional, and built-in, Digital/Analog Converter Module stands out due to the extremely short and distortionless Current Injection and Load-Effect Free analog circuitry — and contributes further to the music's impression of effortlessly unfolding.
The result: Music no longer sounds digital, but warm, open and powerful, as if it were from a superior analog sound source.
BDCD1: Simply the quintessence of both worlds.
One truly uncommon concept is a CD transport with belt drive. Why should a belt drive be applied although almost all other CD player work with direct drive?
Just measurement results don't really serve as a decision maker, but this was already true in analogue ages: In measurement the direct drive turntables outperformed the belt drive, just in terms of sound within the higher grade class of turntables belt drive types outperformed their direct driven counterpart clearly.
In
the case of CD players the situation seems to be quite similar. There is one difference: While turntables rotate with a constant
velocity a CD player constantly adjusts the speed depending on the play
time position for a constant data stream. Sometimes this fact is
regarded as an argument against belt driven CD players, but the speed
changes are slow and continuous and thus a belt drive can technically
manage this challenge. Rapid changes in speed just happen during title
skip. Naturally a belt driven, flywheel-type CD player reacts somewhat
slower here. But sacrificing a higher level of musical enjoyment for
faster track access times? This might be too disadvantageous a
sacrifice.
Superlink & SPDIF Interfaces
For transmitting digital audio signals besides the established SPDIF-compatible interfaces (AES/EBU 110 Ohm, coaxial 75 Ohm and optical Toslink) there is the exceptional and consequent “Superlink”. Unlike SPDIF transmission the different digital audio signals are not merged to one single signal stream and decoded to separate signals again after being received by the DAC.
SPDIF
surely makes sense from the commercial point of view, but Superlink is
the solution without compromise, which requires 4 times of
interconnection cables but skips any coding process. Left/right-clock,
bit-clock, digital audio music data are transmistted from the
CD-transport to the DAC while the master-clock is generated inside the
DAC and sent to the CD-transport. The transmission is done with 4 x
75-Ohm BNC cables with impedance matching.
Superlink results in a more intense link to the music, wider and more
realistic sound-stage, more details and beautiful sound colours.
Power Supply
B.M.C.'s CD transport uses an advanced switching power supply, with active primary voltage filtering and separate transformers for display, motor, logic and audio circuitry on digital and analogue domain.
Additionally there is complex voltage stabilisation separately in front of each functional group.
Optional Upgrade to a CD Player
By adding the digital-to-analogue converter module the belt drive CD transport can turn into a complete CD player with analogue output.
The digital signal performance is optimised by a clock
synchronisation circuit right in front of the DAC-Chips. All digital
signals are re-timed to the local master clock and thus the point of
lowest jitter is at the DAC-Chip where the analogue music signal is
made.
The conversion is made by two 24-Bit / 192kHz TI/Burr-Brown
PCM1792 chips with current output.
The output current is filtered and converted in to an output
voltage by discrete, fully balanced I/V converters, which operate
feedback free. Thanks to the special “Current Injection” circuitry a
maximum of sound quality is preserved, which is buffered with the
unmatched “LEF” driver circuit keeping all sonic details.
Originally those circuits were designed to put focus on the sound quality and leave the measurement specifications second, but the present standard is on a level that leaves no need for such choice: Both are on top level and the sound is class of their own.
The combination of a belt driven CD transport (belt-drive, precision bearing, CD stabiliser with flywheel effect) and consequent digital signal interconnection, as well as an optional DAC with advantageous technology concludes in a musical performance never revealing its digital origin.