TentLabs is founded and headed by Guido Tent, born in 1967 close to Eindhoven, the Netherlands. Guido studied analogue electronics and graduated on the subject of linearity of (directly heated) triodes at a company called deJongSystems. For a few years he worked with that company, where he gained massive experience on design and repair of tube amplifiers, though limited prospects made him decide to change jobs and join Philips Semiconductors. He was involved in the field of EMC and signal-integrity (application, design and innovation of silicon). After gaining 5 years experience he changed over to product development at Philips Optical Storage where he worked on the first digital DVD recorder (Philips DVDR1000). He proceeded developing high speed DVD recording (mainly for PC industry) and designed electronics for the first generation of blu-ray recoders.
Tentlabs DIY CD player
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This DIY version fills the gap between much cheaper multi format playback devices and highly priced CD players. This machine plays back CD, CDr and CDrw discs, it does not handle higher resolution formats like SACD or DVD audio (but CD playback on this player sounds much better than SACD on currently popular multi format machines). It has both analog and digital outputs. An optional module accepts SPDIF and USB audio as inputs, which converts the player to a universal playback device for either discs or PC based audio files. The development of this module is ongoing, as we strive for the lowest obtainable jitter values, it will become available in Q2/8. This module can be retrofitted in the tentlabs CDP. The player uses the well appreciated Philips CDproM LF drive, ensuring secure playback of discs. It is clocked by a separate low jitter Tentlabs clock and puts out its' data using the I2S digital interface format, which intrinsically is independant to jitter.
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. The DAC runs at 48fs, hence does not support I2S output 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.
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. |