Delivery time approximately 2–3 weeks

CD-7 HE

• Redbook CD drive (transport)

• Integrated regenerative power supply

• Uses a Philips CDM-4 swing-arm laser

• Integrated HDMI-IIS, AES, BNC, and RCA coaxial outputs

• Integrated 10 MHz input for external master clocks

New features in the CD-7 HE

1. The integrated regenerative power supply delivers exceptionally clean power and ensures detailed, transparent reproduction with full musicality.

2. Equipped with an on-board FPGA that provides a high-performance hardware S/PDIF demodulator—instead of conventional standard ICs such as the DIR9001, WM8805, or the AK411X series.

3. Uses an Accsilicon AS318B 45.1584 MHz femtosecond oscillator. The 11.289 MHz clock signal is generated via the FPGA, achieving an approximately 12 dB improvement in phase noise compared with the oscillator signal alone.

4. Clock and FIFO technologies for the output data ensure precise synchronization between data and clock signals for maximum jitter immunity.

5. Four HDMI-I²S output formats provide maximum compatibility with most commercially available DACs worldwide. The format is switched internally in the FPGA without mechanical switches, preventing signal and clock distortion.

6. An integrated ultra-high-speed broadband isolator separates the digital signal processing from the output buffer stages to prevent the transmission of digital noise to the external DAC.

7. The external clock input also features an integrated ultra-high-speed broadband isolator that prevents ground-current noise from the external clock system from impairing the purity of the reference clock.

8. For uncompromisingly clean power, the device features a total of 17 regulated power supplies:

   • A: 1 pure Class A power supply for the HDMI, AES, and coaxial output buffers.

   • B: 2 pure Class A power supplies for the regenerative power supply circuit.

   • C: 4 DC servo power supplies for the HF stage, DSP, FPGA, and other digital signal-processing circuits.

   • D: 10 high-speed linear power supplies for the remaining circuit components.

The regenerative power supply

Audio is life, and the power supply is the water: Pure water creates wonderful life—clean power produces outstanding sound.

The regenerative power supply acts like an independent power generator integrated into the device. It blocks virtually all interference from the mains and supplies the CD-7 HE with exceptionally clean power for a natural, analog sound.

The mains AC is converted into direct current (DC) via an input transformer and powers the sine-wave generator and driver stages through Class A power supplies. The parallel-connected Class A power supply features very high input impedance (to prevent feedback into the signal) as well as low output impedance with high speed and linearity.

A fully balanced sine-wave generator produces an extremely low-distortion 50 Hz wave. Through balanced amplifiers and robust output stages, it drives two output transformers that deliver separate, exceptionally clean AC power to the digital processors and output buffer stages.

Development features of the regenerative Audio-gd power supply:

• Analog wave generation: Measurements with the Audio Precision SYS-2722 demonstrate that purely analog sine-wave generation has significantly lower distortion than digital generation.

• Analog driver stages: Although digital driver stages offer higher efficiency, fully analog driver stages sound far more musical and natural.

• 50 Hz frequency: A 400 Hz wave would offer higher efficiency; however, 50 Hz is well outside the most sensitive range of human hearing and is crucial to achieving an analog sound character.
  
  

HDMI-I²S output

The CD-7 HE's HDMI-I²S output supports four configurable formats (the enclosure cover must be removed for adjustment). Customers can inform us of their DAC's HDMI-I²S input format when ordering so that we can preconfigure it before shipping. Without specific instructions, the unit is shipped configured to Format 1 by default.

Format 1

Format 2

Format 3

Format 4

Technical details

Important note before purchase

1. The CD-7 HE is equipped with a CDM-4 laser with fixed laser power calibrated to the optimal level. The laser power is deliberately not increased to force the reading of problematic media, as higher power causes signal distortion, reduces sound quality, and shortens the laser's service life.

   Therefore, heavily soiled or scratched CDs may still be readable by players with newer-generation laser units (such as CDM12 or DVD lasers) or devices with artificially increased laser power, while the CD-7 HE may refuse to play them.

   The unit reads clean, minimally scratched original CDs with absolute reliability.

   This development approach ensures an exceptionally long service life for the CDM-4 laser.

2. The CD-7 HE is a pure CD transport without an integrated D/A converter (DAC). For audio playback, it must be connected to an external DAC.