Valve Audio Devices DAC-10 User Manual - Technical Information
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Technical information
DSD64/DSD128 playback
(DAC-‐10 DSD)
:
Our dedicated DSD (Direct Stream Digital) playback platform passes the USB interfaced DSD
Left and Right channel bitstream data through 1bit drivers and onto a high precision, double
differential FIR (Finite Impulse Response) active filter. The signal is then passed through a
passive analogue filter to retrieve the pure audio, which is then amplified by the vacuum tube
triodes.
Use of this technique provides the purest possible representation of the DSD stream as music.
The analogue frequency response of our DSD playback is a staggering: 10Hz to 120 kHz with
DSD128 and 10Hz to 100 kHz with DSD64 with a drop at 120kHz of only 3dB.
DSD noise shaping technique frequencies are significantly higher than our 120kHz pass band. In
addition, professionally distributed DSD recordings do not carry real information above the
human audible spectrum, so there is no `ultrasonic energy` there to pass into your system.
Therefore, we decided to open the analogue frequency response in our DSD playback trusting
that music lovers will experience how much can be really perceived in the music reproduction.
The S/N ratio of VAD DSD direct filtered playback is 110dB with DSD64 and 113dB with DSD128
Crucially, our DSD playback method is free of digital processing and separate from the PCM
circuitry.
SPDIF sources playback:
SPDIF bi-‐phase signal is interfaced to a high frequency, high input impedance triode valve
configured in balanced digital mode and precisely matched to our selected SPDIF receiver in
balanced digital mode. This method gives the benefit of the DAC-‐10 / DAC-‐10 DSD being highly
immune to the sometimes-‐poor electrical signal quality from SPDIF transports and/or digital
coax interconnects, which can influence the sound.
A better transport will improve the overall sound. However, the DAC-‐10 / DAC-‐10 DSD will
sound exceptionally superior with even the most basic SPDIF signal sources and digital
interconnects.
PCM USB Audio playback:
High-‐end asynchronous USB audio is I2S interfaced to the PCM 32bit decoding stage with two
mono converters (L&R). The stage is free of any post filtering and coupled I/V to two mono
vacuum tube triode analogue output stages.