Longdog Audio VDt1 24/192 DSD Valve DAC

Designed and manufactured in the UK, the LDA VDt1 DAC has been designed by Nick Gorham of Longdog Audio. Housed in a full width case and featuring many unique traits including a fully balanced valve output stage featuring 5687 dual triodes, the DAC handles file resolutions up to 24/192 as well as DSD. The combination of valve output stage and DSD material gives the listener a unique insight into the recorded material. The most analogue sounding digital music yet heard. Available to buy now on the MCRU website.

SPDif inputs: 2.

Galvanic isolation with high performance pulse transformers.
RCA connectors with 75 ohm impedance.
110 Ohm AES XLR inputs available on request.
Supported speeds from 16bit/44.1k to 24bit/192k
SPDiff Reciever supplied by three separate ultra low noise voltage regulators.

USB Input: 1.

Powered from Host computer, Galvanic isolation between Host PC and DAC, prevents noise from the host computer being coupled into the DAC.
USB Audio class 2.0 interface.
Driver free on Linux and OSX host systems.
Simple driver installation on windows.
Speeds from 16bit/44.1k to 24bit/192k (32bit accepted).
DSD over USB supported, 64bit DSD, automatic switching between PCM and DSD

DAC:

AK4396 DAC selected for best subjective sound when used in balanced out mode.
DAC powered by two ultra low noise voltage regulators.
I2S and DSD input isolated from receiver to avoid noise transfer between stages.
Analog output from DAC taken directly to output buffer, no op-amps, capacitors or additional solid state devices in the signal path once it has left the DAC chip.

Analog stage:

Fully balanced valve output stage using 5687 dual triodes, and custom Sowter output transformers, with nickel cores and balanced winding patterns. Use of balanced design ensures distortion levels equal to solid state    output stages, but with the sonic qualities that only valves can deliver.     All resistors in signal path are high quality Takman carbon film types.
Output via high quality RCA sockets, fully balanced XLR output available on request.
Output signal level 2.18v RMS full scale (single ended).

Power Supply:

Digital board has 4 stages of pre regulation using low noise regulators, feeding 9 individual ultra low noise regulators mounted next to the driven device. Custom board design providing isolated ground paths between stages to reduce noise induced jitter to a minimum. High quality parts used throughout digital stage to ensure optimum performance.

Analog board contains three regulated power supplies, one for the digital board main supply, one for the output stage valve heater supply, and a valve regulated high voltage supply using high voltage mosfet and EF86 pentode design. Low noise HT supply ensures ultra low analog noise floor.

Custom UK wound toroid transformer, with oversized core, shield and hum band, supplies power to the unit.

The DAC is on demonstration at the MCRU showroom in Huddersfield and will shortly be reviewed in Hi Fi Choice magazine.