"Now, The latest DAC is called DAC-10 DSD Digital to Analogue Converter and its launch is expected at the end of the month. Latest machine is a whole new universe. If the original VAD-1 s we had been demoing was a already a no brainer THE TEN is taking things even further. It comes with new inputs layout , remote controlled gain, by radio by the way, a unique circuit employing valve on digital inputs and finally the most wanted on today’s DAC market – native DSD input, not cheap threal back conversion via PCM as it appears in 99% of currently produced dacs on the market. The DSD interface in VAD’s completely new and original approach, using separate USB input exclusively. Another thing worth mentioning is an auto-bias on driving valves, so now all the tubes can be rolled, from rectifiers to the output octals, which are still famous 6SN7.Driver can be changed between 6N6P and popularized by B.A.T , so called supertriode 6H30. Please have a look at the back of the DAC TEN to see how it appears now."

Of course what was already best – their excellent chassis had been kept, this is company’s trademark which is immediately recognizable, but it had been finally mastered and the finish quality is now last to the end. Please read bellow to find more about all upcoming features :
DAC-10 DSD Digital to Analogue Converter (DAC)

If you think PCM digital audio is good, then you have to try DSD (Direct Stream Digital), which is considered to be the highest-quality digital audio storage method currently available. By creating the DAC-10 DSD, you now really can hear what the artist intended.

A true dual mono design based around our own 24bit dual DAC circuitry and DSD module, the DAC-10 DSD is a non-compromising design that features valve circuitry operating in pure Class A mode to give outstanding performance.
Uncompromising DSD and PCM digital technology

The DSD (Direct Stream Digital) module in the DAC-10 DSD replaces the AES-EBU socket of the standard DAC-10 with an additional USB socket dedicated to DSD playback. To gain the purest DSD stream possible, we have designed a system that removes any DSD noise-shaping high frequency carrier present in the signal and `pink noise` above 30kHz. All DSD data is passed through 1 bit ‘driver gates’ and then applied to a high precision, double differential FIR (Finite Impulse Response) filter before an additional passive analogue filter. The retrieved pure audio signal is then amplified by the valve analogue output stage. To keep this delicate circuitry separate from any interference, VAD’s DSD playback module is free of digital processing and completely separate from the PCM circuitry.
The DSD circuitry is retro-fitable to those wanting to upgrade DAC-10 PCM-only DAC’s in the future.

The SPDIF digital input (RCA COAX, BNC, and TOSlink optica) 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 DSD being highly immune to the sometimes-poor electrical quality of the signal from SPDIF transports and/or digital coax interconnects, which can detrimentally influence the sound.

The DAC-10 DSD also includes a USB 2.0 input with asynchronous (32bit / 192kHz ) high-end interface, which is connected directly via the I2S interface to the PCM decoding stage with two mono converters (left and right). The stage is free of any post filtering and coupled I/V to the dual mono valve analogue output stages.

Based on our own ‘Sound Pure Design’, the DAC-10 DSD features virtual signal pass through circuits, with zero low-pass or high-pass filtering in the audio frequency range or any up-sampling in the digital domain. Unique to the design, the SPDIF digital processing includes an HF Triode valve in its circuit and the built-in 32-bit/192kHz asynchronous USB is connected via i2S transmission standard, for the very purist data transmission possible. For those wanting to hear back the very best digital files available, DSD connectivity is included via a separate USB connection in the DAC-10 DSD, in place of the AES/EBU socket on the standard model. Inputs include RCA COAX, BNC and TOSlink optical with outputs via stereo single-ended RCA or balanced XLR sockets.
Valve analogue output stage

The triode valve analogue output stage operates in pure Class A and is point-to-point engineered for the very best performance possible. Featuring NOS (New Old Stock) valves, the stage consists of a pair of 6SN7 drivers, a pair of CV574 rectifiers and a pair of 6N6P double triode valves, all of which have been selected and matched for reliability and robustness. Wired in pure Class A, output is via a stereo pair of RCA single-ended and XLR balanced analogue outputs.

To precisely match the output of the DAC-10 DSD to any pre or integrated amplifier, a specially designed direct-coupled remote-controled analogue gain control is fitted to the front panel. For digital-only systems, this gain control can also facilitate direct connection to power amplifiers. Remote control handset included.
Power supply

As with all audio products, power supplies are extremely important and, with the DAC-10 DSD, we have paid particular attention by not only separating out the digital and analogue power supply sections but also the left and right channels. All power supplies are designed for the specific application, are choke loaded and feature inductors, polymer and film capacitors and ‘series’ resistor-less components to provide the purest power flow possible.

Our unique casework is designed as a monocoque structure with the aim of giving the circuitry an extremely high mechanical rigid base, EMI and RFI screening and vibration damping. Polymer coated with additionally polyurethane to ‘silence’ it from any mechanical ringing, the only structural parts fitted with screws are the aluminium top cover and removable valve cover. It is also directly fully grounded via the safety `earth` pin in the fused IEC socket. Direct grounding provides the highest electrical safety and means that the EMI/RFI screen really is a `screen`, not just a piece of metal in the way of interferences.
UK design and build

With over 90% of the parts sourced locally and totally hand-built in the UK, we have used the latest analogue and digital components mixed with NOS (New Old Stock), with each component selected for its sonic characteristics and reliability. Each unit is soak tested for 36 hours prior to shipping and we are so confident with the reliability of our products, that we issue a seven-year guarantee from date of purchase (valves are guaranteed for 90 days).

Valve Audio Devices digital 24bit dual DAC circuit, directly coupled to our bespoke designed triode valve analogue output stage with:
selected pair of 6SN7
selected pair of 6N6P
special series pair of CV574 rectifiers
Dedicated DSD USB input.
Unique, HF Triode valve based digital processing for SPDIF
Built-in asynchronous 32bit/192kHz high-end audio USB interfaced to digital to analogue conversion stage using i2S transmission standard.
Our own design highest quality digital board, manufactured for Valve Audio Devices in the UK is populated, soldered and tested by hand.
Unique monocoque chassis to give all components the very best platform for optimum performance.
Highest quality components specifically selected for their sonic characteristics.
Purpose designed, choke loaded, PIO capacitors filtered power supplies include two valve rectifiers and in total four mains transformers – being individual for each stereo channel, separate for valve SPDIF digital processing, USB, Digital to Analogue Converters and valve filaments.
No compromise, bespoke power supplies for digital and analogue domains of the DAC circuit, filtered by inductors, polymer and film capacitors.
Full dual mono design philosophy.
Valve circuits operating in pure Class A.
Purely point to point engineered valve analogue output stage.
Ultra-short primary “signal path” utilizing aerospace technology silver wiring.
Sound Pure Design, without low-pass or high-pass filtering in the audio frequency range.
Sound Pure Design, without up-sampling of the signal in the digital domain.
Built-in high quality AC mains filter selected from Schurter
Our own special selection of silver mica and paper in oil capacitors for audio signal.
SPDIF – RCA COAX, BNC, TOSlink optical and AES/EBU digital inputs.
USB 2.0 input with asynchronous (32bit / 192kHz ) High-End Audio USB interface.
16 and 24bit resolution with 32 to 192kHz sample rate support.
Digital signal SPDIF `lock` indicator and digital `reset` functions.
RCA single ended analogue and XLR balanced analogue outputs.
Specially designed direct coupled analogue, remote-controlled gain control. Remote control handset included.
Valve `rolling` ready for 6SN7 drivers and CV574 rectifiers.
7 Year Manufacturer’s Warranty for parts and labour (excepting vacuum tubes which are guaranteed for 90 days).
Unique, durable and reliable – UK Patent Office Registered Design.
Classic, solid engineering designed with up to date specs and features.
Our unique casing provides excellent EMI/RFI screen having a 4mm thick grounded metal between each section (mains transformers/valve module/digital circuitry) and solid aluminium top cover.
Ultra durable 6mm thick – laser/nitrogen cut, milled and hand brushed stainless steel silver or piano black front panel
DAC-10 casing includes: removable, protective, metal valve cover.
Fully upgradeable product – should digital audio reproduction progress further than 24bit/192kHz and with the real sound being a justified principle, Valve Audio Devices will offer adequate upgrade for already existing products at any point in time.
Over 90% of the DAC-10′s components come from the UK.
100% hand-crafted in the UK.
As well as being designed purely for the music, the DAC-10 is also conceived to be a very long lasting and environmentally conscious product (not a `throw away` box).
Our design-specific circuit solutions are patent pending.
Each of our unique valve DACs is hand built over many hours and passed through rigorous 36 hours `burn-in` test.
Supplied set of 7 valves in the DAC is expected to work faultlessly for a minimum of three years constant operation (this has been tested and proved by us during our extensive R&D process).
Very high quality, tight tolerance ceramic valve bases and our selected valves, allow us to ship the DAC with vacuum tubes ready fitted.
DAC is shipped to Customers in `made to measure`, robust, aluminium/composite flight case.

Matej Isak. Mono and Stereo ultra high end audio magazine. All rights reserved. 2006-2013. ..:: None of the original text, pictures, that were taken by me, links or my original files can be re-printed or used in any way without prior permission! ::..