DIY CD player / CD transport
General Description
Ever wanted to build your own CD player ? Now you can with a complete range of modules, supporting the building process. Below is a short overview of the modules. Please download the CDpro Application Note which describes the building process and all required interconnections.Technical description
Drive
The heart is the well appreciated Philips CDproM LF drive, ensuring secure playback of discs. It is clocked either by its own clock (industrial quality) or by a separate low jitter Tentlabs XO3.2 clock (high end audio quality) and puts out its' data using the I2S digital interface format, which intrinsically is independant to jitter as well as SPDIF, reclocked by that same low jitter clock.
Display / controller
This modules provides communication between the user and the CDpro. A VFD display shows all relevant disc information. While the button Interface translates most normal functions to the drive, an Infra Red (RC5) remote interface provides virtually all commands.
DAC
The DAC takes in the I2S data, reclocks it and processes the 16 bits data to be accepted by the 20 bit DA converters. These run in non oversampling mode, main advantage is that less jitter enters the DACs due to the absence of a digital filter and the DACs run at a lower bitclock rate which makes their life much easier. Prior to entering the PCM1704 DACs, all data is reclocked again. This takes place by the onboard Tentlabs master clock. This clock is powered by a fast, low noise shunt regulator, of which in total 6 are present. 4 others feed the analog supplies of the 1704's and the last one the reclocking circuits. Another 6 regulators take care of the supply of other, less critical, circuitry.
IV converter and output stage
The IV converter uses an E88CC valve as transimpedance amplifier. It fully operates in the current domain, and is a new and novel design. The advantage over existing tube based output stage is the low input impedance (typically well below 1 ohm) which reduces the distortion generated in the DAC chips compared to the situation when these are loaded with say 100 ohm, which seems common practice these days. After the E88CC stage, a passive filter follows. The actual IV conversion takes place using an Audio Note tantalum resistor, signal coupling is achieved using Audio Note copper foil paper-in-oil capacitors. 2 pairs of outputs are available, a straight output with a moderate 2.5 k-ohm output impedance, and a buffered one with output impedance well below 200 ohms. The IV stage is fed by a custom made toroidal transformer, the well regarded 6X4 takes care of high voltage rectification.
Power supplies
The IV converter, DAC and drive all have their own toroidal power transformer. The drive is fed by 2 external Tentlabs power supplies, a third one supplies the Display. The power supplies incorporate Schottky Barier diodes, low ESR capacitors and a low drop discrete design regulator. The 9V regulator inhibits a fast switch-off option to ensure proper shutdown of the CDpro drive.
Wiring
All required wiring is available as completed assemblies.
• CDpro power cable
• DSA interface cable (CDpro - Display)
• Display power
• I2S interface (CDpro - DAC)
Orders and information
Go to the shopDownload area
• CDpro User manual
• CDpro 2M datasheet
• CDpro Application Note
• CDpro center hub removal