BMC Audio BDCD 2 - The belt drive CD player feature newly "Current Injection" 32Bit DAC, LEF driver stages delivering a sound quality unreached for a CD player and all new TXCO-Clock with ultra low phase noise and extremely low jitter.
"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 tranquility. A patented belt drive with high inertia, in the form of an acrylic-stabilizer, applies this principle to B.M.C.'s BDCD2 CD Belt Drive Player/Transport."
Belt Drive is More Than Just a BeltBDCD Mechanics
Belt drive decouples the motor vibration from the CD
The CD turns on a precision bearing, analogous to a turntable bearing
A CD stabilizer removes vibrations and resonances from the CD
Due to the high inertia of the stabilizer any rotation is quiet and smooth.
Quiet operation of the servo circuit instead of multiple 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 BDCD2's music-optimized, belt-driven flywheel drive is reflected throughout the BDCD2 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.
The BD2 transport is also available as BDCD2 with Digital/Analog Converter which 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.
More about the BDCD2
One truly uncommon concept is a CD transport with belt drive. Why should a belt drive be applied although almost all other CD players work with direct drive?
Measurement results alone don't really serve as a good decision maker, but this was already true in analogue ages: In measurement tests the direct drive turntables outperformed the belt drive, but in terms of sound within the higher grade class of turntables belt drive types clearly outperformed their direct driven counterpart.
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 timesmay very well be too disadvantageous a sacrifice.
Superlink & SPDIF Interfaces
Instead of transmitting digital audio signals via 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 a commercial point of view, but Superlink is the solution without compromise. It requires four 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 four 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 colors.
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.
CD Player Version BDCD2
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 optimized by a clock synchronization 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 32-Bit / 758kHz TI/Burr-Brown PCM1792 chips with current output.
The output current is filtered and converted 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 the 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 a choice: Both are top level and the sound is in a class of its own.
BDCD2 DACThe combination of a belt driven CD transport (belt-drive, precision bearing, CD stabilizer with flywheel effect) and consequent digital signal interconnection, as well as an optional DAC with advantageous technology results in a musical performance never revealing its digital origin.