New British valve audio designer Valve Audio Devices (VAD) has launched its debut offering: the DAC-10 digital to analogue converter. Designed and hand-built in the UK, the converter comes int two variants; PCM only (DAC-10 at £6499.95) or PCM and DSD (DAC-10 DSD at £6999.95). Both models being available in either piano lacquer gloss black or silver. The DAC-10 is a dual mono design based around proprietary 24-bit dual DAC circuitry and coupled to a bespoke triode output stage. The standard model has USB, coax, BNC, Toslink and AES/EBU inputs, the DSD substituting a dedicated DSD USB socket in place of the AES/EBU. Both models feature virtual signal pass through circuits, with no low- or high-pass filtering in the audio band nor upsampling in the digital domain. The S/PDIF digital processing includes a triode valve in its circuit and the 32-bit/192kHz asynchronous USB is connected via the i2S transmission standard.
The analogue output stage operates in pure Class A and is point-to-point wired. 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. Output is via a stereo pair of RCA single-ended and XLR balanced analogue outputs. To precisely match the output of the DAC-10 to any preamp or integrated amplifier a remote analogue gain control is fitted to the front panel, in digital-only systems, this control can also facilitate direct connection to power amplifiers. VAD has paid particular attention to power supplies by not only separating out the digital and analogue sections but also the left and right channels. All power supplies are choke loaded and feature inductors, polymer and film capacitors and 'series' resistor-free components. The casework is designed as a monocoque structure with the aim of giving the circuitry a mechanically rigid base as well as EMI and RFI screening. Polymer coated with additionally polyurethane to kill mechanical ringing, the only structural parts fitted with screws are the aluminium top cover and removable valve cover. It is also directly grounded via the earth pin in the IEC socket, an approach which VAD considers “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”.