The Well-Tempered Computer, an introduction to computer audio

Friday, January 7, 2011

Acoustic Plan DigiMaster and DriveMaster

In spite of the small size of the CD transport/DA converter combination, Acoustic Plan's  DigiMaster and DriveMaster meets the superior quality demanded by high-end audiophiles. The DriveMaster is equipped with the famous Philips CDPro2 which is also used in studios, test equipment and continuous music reproduction units. This together with the special suspension of the drive module ensures a highly accurate readout is maintained. 


The DriveMaster has two digital outputs, a SPDIF with BNC connector and a non standard I2S output. The I2S connection to the DigiMaster D/A converter allows a direct data transfer without any converting of the SPDIF signal. An optional full metal remote control is available that ensures ease of operation.




The DigiMaster D/A converter is small and simple.  The USB as well as the SPDIF inputs have 192kHz/24 bit receivers and they pass on the data stream to the 24-bit R2R PCM1704U-K converter. Neither upsampling nor oversampling is used and this keeps the data as pure as possible. The USB data transfer works in an asynchronous mode, whereby the clock is determined by the high precision clock generator in the DigiMaster. To avoid ground loops between the PC and the DigiMaster, the USB receiver circuit is powered by the PC, whereas inductive couplers provide the galvanic separation between the two units.

The minimalist philosophy of the circuit design is continued in the analogue filter and in the analogue output stage. For that reason, only analogue filters are used to cut off the undesirable ultrasonic frequency range. Depending on the sampling rate, the filters are switched to the proper cut off frequency. The analogue filters consist of custom made precision inductors and capacitors. A pure tube output stage amplifies the small analogue signals and provides a low output impedance to partnering electronics.

All devices of the Master series have an external high quality switching power supply as standard. They meet the latest energy saving directives and have a medical approval for low electromagnetic radiation. As an upgrade, a power supply with linear regulation of Acoustic Plan’s own production is available. This power supply is able to supply two devices of the Master series. The software of both devices (DigiMaster and DriveMaster) is developed "in house" exclusively by Acoustic Plan.

Designed to offer a very high level of reproduction they offer the following specification:

DigiMaster DAC
- USB input for high resolution audio format up to 192kHz/24bit asynchronous mode, input ground free via iCoupler.
- SPDIF input for high resolution audio format up to 192kHz/24bit, BNC connector, transformer coupled
- I2S input for DriveMaster
- Multibit D/A converter
- no oversampling
- no upsampling
- no digital filter in the signal path
Analogue section:
- analogue low pass filter (cutoff depending on sampling rate) and purely passive.
- tube output stage
- no semiconductors in the audio path
- includes a software driver on a CD for Windows. It is compatible with Win XP/Win Vista/Win 7 and an must have a USB 2.0 interface. For Mac and Linux no driver is needed.
- output: 2V/ 200 Ohm
- Price €2500 (approx £2000)

DriveMaster Transport:
- Phillips CDPro2M transport
- SPDIF output with BNC connector
- I2S output for DigiMaster DAC
- Optional full metal remote control
- Price €2500 (approx £2000)

Dimensions: 106mm x 125mm x 260mm
Weight: 2kgs each

Additional high quality upgradable "plug in" power supply is also available offering the user a "plug in" upgrade path for even better sound quality.