VAD DAC-10 User manual

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Valve Audio Devices
DAC-10 / DAC-10 DSD Digital to Analogue Converter
User Manual
Version 2.1

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Introduction
The Valve Audio Devices DAC-10 / DAC-10 DSD valve DAC is an exquisitely engineered, hand-
uilt, point-to-
point wired unit employing specifically selected components.
It is designed for the audio purist and refined over countless hours to produce exceptional high
definition sound with unparalleled musicality.
Every component is selected with sound quality as the highest priority and its specially
designed dual mono valve analogue stage, ultra-short “signal path” and advanced dual mono
digital to analogue conversion stage provides the optimum environment for digital audio
play ack from a variety of signal sources.
When matched with similarly high quality components, the DAC-10 / DAC-10 DSD achieves a
standard of micro-dynamics, resolution and speed to satisfy the most discerning of audiophiles.
Closing the gap to the original sound and delivering unparalleled musicality, with all of the
original nuances, has now ecome closer than ever.
The DAC-10 / DAC-10 DSD stands comparison with the world’s finest reference DACs –
regardless of price - and comes with a 7-year Manufacturer Warranty. It has een designed and
uilt with relia ility in mind and will last a lifetime with appropriate care.
Data Formats
The DAC-10 / DAC-10 DSD is capa le of automatic recognition of sampling rates from 32 to
192kHz and it rates of 16-24 it from SPDIF/AES3 digital audio compati le sources through:
•COAXIAL, TOSlink, BNC and AES/EBU (AES/EBU DAC-10 only)
•USB Audio 2.0 input dedicated for PCM audio files up to 32 it/192kHz
•USB Audio 2.0 input dedicated for DSD64 datastream (DAC-10 DSD only).
In t e DAC-10 DSD, t e second USB input replaces t e AES/EBU SPDIF input of t e DAC-10.

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Tec nical information
DSD64 playback (DAC-10 DSD):
In our dedicated DSD (Direct Stream Digital) module, the USB interfaced DSD Left and Right
channel itstream data is passed through 1 it driver gates and applied to a high precision,
dou le differential FIR (Finite Impulse Response) filter and then a passive analogue filter. This
removes any DSD noise shaping high frequency carrier present in the signal and pink noise
a ove 30kHz. Retrieved pure audio is then amplified y vacuum tu e triodes. Use of this
technique provides the purest possi le representation of the DSD stream as music.
Our DSD play ack module is free of digital processing and completely separate from the PCM
circuitry.
SPDIF playback:
SPDIF i-phase signal is interfaced to a high frequency, high input impedance triode valve
configured in alanced digital mode and precisely matched to our selected SPDIF receiver in
alanced digital mode. This method gives the enefit of the DAC-10 / DAC-10 DSD eing highly
immune to the sometimes-poor electrical signal quality from SPDIF transports and/or digital
coax interconnects, which can influence the sound.
A etter transport will improve the overall sound. However, the DAC-10 / DAC-10 DSD will
sound exceptionally superior with even the most asic SPDIF signal sources and digital
interconnects.
PCM USB Audio playback:
High-end asynchronous USB audio is I2S interfaced to the PCM decoding stage with two mono
converters (L&R). The stage is free of any post filtering and coupled I/V to two mono vacuum
tu e triode analogue output stages.
Power supply:
Power supplies are independent for digital and analogue and Left and Right channels. All
power supplies are inductor (choke) loaded, series resistor-less and espoke designed.
Vacuum tube analogue output stage:
The DAC-10 / DAC-10 DSD vacuum tu e triode analogue output stage is point to point
engineered to operate as:
1. PCM stage differential audio signal coupling (transformer-less).

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2. DSD stage audio signal coupling.
3. Gain regulation - part of this function implemented in DC mode.
4. Signal dependent varia le tu e iasing.
5. Voltage amplification.
6. SE and alanced out signal stage.
The whole tu e circuit is operating in pure Class A.
Casing:
The unique VAD casing is designed as a monocoque structure with the fulfilled aim for
extremely high mechanical rigidity, EMI and RFI screening and vi ration damping.
It is polymer coated and additionally polyurethane `silenced`.
The only structural parts fitted with screws are the aluminium top cover and valve cover.
Electrically the casing is directly fully grounded via the safety earth pin in fused IEC socket.
Direct grounding provides the highest electrical safety and also means that the EMI/RFI screen
really is a `screen`, not just a piece of metal in the way of interferences.
Used components:
During long R&D process, all compone
nts were selected for the overall sound enefit of
the whole design without compromises.
The separate components count of the DAC-10 DSD is 600 and include: selected paper in oil
and silver mica capacitors, 0.1% tolerance foil resistors, selection of Sanyo OsCon and other
polymer caps, Ru ycon ZLJ, ZLH, ZL, Panasonics FC, FM, FR, car on resistors and metal
resistors, silver wire and tinned copper wire, fast RF relays and old fashion solder tags, chosen
top quality linear voltage regulators, Schottky rectifiers, FR diodes and valve rectifiers,
inductors, ceramic valve ases, newest digital IC`s and NOS (New Old Stock) valves, non-
magnetic screws, copper rails, Teflon, silicone, selection of C0G,NPO,X7R,MKP,MKS capacitors
and other parts including many VAD secrets. All components are new and current production
(apart from NOS vacuum tu es), sourced mostly from UK suppliers.
All designed and chosen y us for you to enjoy t e music

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CONTENTS
Introduction 2
Technical info 3-4
Unpacking 5
Connection 6-7-8-9
Before Switching ON 10-11-12
Safety and other information 13-14
Specifications 15-16
Warranty Information 17-18
Warranty registration form 19
Unpacking
In the flight case you will find the following:
•1 x VAD DAC-10 / DAC-10 DSD valve DAC
•1 x RF remote control
•1 x Power cord
•1 x Hex key (for removing the valve cover)
•User manual
Remove all contents. Keep the flight case in case of need to ship the DAC-10 / DAC-10 DSD.
Place the DAC on a sturdy surface (e.g. hi-fi rack or isolation platform) and plug in the power.

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Connection
VAD DAC-10 inputs: VAD DAC-10 DSD inputs

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Digital inputs
DAC-10 digital audio connectivity:
•AES/EBU alanced digital audio input
•BNC SPDIF digital audio input
•COAXIAL SPDIF digital audio input
•TOSlink optical SPDIF digital audio input
•USB 2.0 audio PCM input (up to 24 it/192kHz)
DAC-10 DSD digital audio connectivity:
•BNC SPDIF digital audio input
•COAXIAL SPDIF digital audio input
•TOSlink optical SPDIF digital audio input
•USB 2.0 audio PCM input (up to 24 it/192kHz)
•USB 2.0 audio DSD input for DSD64 stream
AES/EBU: Use a screened, twisted pair ca le from the digital output of your CD transport or CD
player to the AES/EBU digital input of the DAC-10 (AES/EBU socket is a receptacle type)
Coaxial: Use a RCA plug terminated, coaxial interconnect of your choice for the COAXIAL digital
input. The ca le for the COAXIAL input should e no longer than 1.5m (5 feet) for the est
result
USB: Use USB 2.0 ca le fitted with USB type B plug terminated for the DAC side. For est
results use a good quality USB 2.0 ca le without any sleeve inductors.
NB - DAC-10 USB interfaces are powered from our on- oard, purpose designed, extremely low
noise linear power supply (not from your USB socket – which is used for data transfer only).
TOSlink: Use prefera ly multi-strand glass fi re type optical audio ca le.
NB - 24 it/192kHz sample rate play ack through TOSlink cannot e guaranteed.
BNC: Use same type of preferred coaxial ca le as used for the RCA Coaxial input, terminated
with the BNC plug.

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Audio outputs:
Balanced: Use screened, twisted pair ca les fitted with 3pin XLR plugs (receptacle type plug for
the DAC-10 / DAC-10 DSD end).
When using the alanced connection, pin 1 is “ground”, pin 2 is “hot” and pin 3 “cold”. Make
sure this complies with your other audio equipment and consult with your dealer for any
necessary modifications.
RCA: analogue interconnects for single ended outputs.
RCA ca les should ideally e no longer than 1.5m / 5 feet etween the audio outputs of the
DAC-10 / DAC-10 DSD and the line level input of your preamplifier or integrated amplifier.
NB - We advise that alanced and un alanced audio outputs are not eing connected/used
simultaneously (possi ility of ground loop on some systems).
Input selector switc es
The VAD DAC-10 / DAC-10 DSD has two, three position toggle switches (1, 2) on the ack panel:
•Switc 1 (SW1) will let you choose etween the AES/COAX, BNC and Toslink inputs.
•Switc 2 (SW2) will let you to exclude the SPDIF and choose the USB Audio options.
In the `middle` position of SW2, SPDIF sources are connected (further selecta le via SW1)
In the `down` position of SW2, the SPDIF inputs are OFF and the internal I 2 S interface
asynchronous USB Audio input is connected for PCM music file sources (example: wav. flac.
aiff.).
AES/COAX SW1 switch position will automatically choose an active signal source etween the
AES/EBU and COAXIAL inputs.
DAC-10 SW2 `up` position is inactive
DAC-10 DSD only
The AES/EBU SPDIF input is replaced y a USB DSD input.

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In the `up` position of SW2, the PCM USB is OFF and the dedicated DSD USB interface is ON for
DSD64 play ack (example: dsf. dff. iso.).
SW2 also activates a separate analogue `path` for DSD play ack.
PCM and DSD
If you have oth formats (PCM, DSD) of music files on your computer connect oth USB inputs
to your computer using quality USB 2.0 ca les.
To play DSD files:
- switch the DAC-10 SW2 switch to DSD position `up`
- choose the DoP itstreaming output format in the options of your computer software
player
To play PCM music files:
- stop the DSD play ack
- switch the DAC-10 SW2 switch to PCM position `down`
- choose the PCM compati le output format in options of your computer software player.
Initial position of SW2 (`up` DSD, `middle` SPDIF, down `PCM`) is not important, your computer
will recognise only one USB input when you determine y SW2 which format you are going to
play.
Please note: your software won’t play native DSD into the USB PCM input or PCM into USB
DSD input.
- If you listen to PCM only: there is no need to connect the second USB ca le to DSD USB input
- If you listen to DSD only: there is no need to connect the second USB ca le to PCM USB input.
- We recommend that the DAC gain control is turned down efore selecting the DSD USB Audio
format - once the output of your software player is set to DSD, the gain can e increased as
needed.
DAC-10 / DAC-10 DSD USB Audio file formats:
PCM music files: Any music file type supported y your computer audio software on Windows
OS and Apple OS platforms - up to 32 it/192kHz
DSD music file types: Windows OS: DSF, DFF/DSDIFF (Developed and tested with JRiver MP18 -
DoP 1.0)
Apple OS: DSF, DSDIFF, SACD ISO images (Developed and tested with Audirvana Plus).

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Before switc ing on
Front Panel
Switc ing on / off
Powering ON: “Flip” the mains power switch on the rear panel of the DAC-10 / DAC-10 DSD
followed y pushing the “Power” utton on the front panel.
Powering OFF: Press the “Power” utton on the front panel of the DAC-10 / DAC-10 DSD.
When in use at home, there is no need to switch OFF the main switch on the rear panel – use
the ack panel switch to completely power off the unit when leaving the house for longer
periods.
IMPORTANT:
Power ON the DAC-10 / DAC-10 DSD approx. 2 min. BEFORE switching ON your other audio
components such as amplifiers etc.
Make sure that the Volume control of your amplifier or pre-amplifier is close to minimum
position (volume turned down).
Switch your other audio components such as amplifiers OFF efore turning OFF the DAC-10 /
DAC-10 DSD.

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Whilst the DAC-10 / DAC-10 DSD will sound super from the moment it is switched on, due to
the nature of valves, it’s sound will improve even further as it warms up. After 20 minutes it
will e on song, after approximately 40 minutes it will reach its peak performance.
To maximise the life span of the valves, it is recommended to minimise the num er of times
that the unit is switched on and off - e.g. where several listening session may e planned during
the course of the day, it is etter to turn the unit on efore the first session and only turn it off
at the end of the final session – rather than on and off at the end of each session. Ideally, the
DAC-10 / DAC-10 DSD would e kept switched on.
The DAC-10 / DAC-10 DSD has the power consumption of 58W during normal operation (with
signal connected).
Gain Control
The remote-controlled signal output level (Gain) control is located in the centre of the front
panel. It is designed to match the output level of the DAC-10 / DAC-10 DSD to a wide range of
preamplifiers and integrated amplifiers ut can also facilitate direct connection to power
amplifiers.
In most circumstances, when used with a preamplifier or integrated amplifier, the output level
of 2Vrms will e achieved at the 12 o’clock position and pro audio level of 4.2Vrms at 3 o’clock
(approximate).
The remote control unit for the DAC-10 /DAC-10 DSD controls the gain control via RF (Radio
Frequency) and allows up and down gain control from the listening position.
Lock
The Lock indicator will “light up” when the compati le digital signal is detected and the input of
the DAC is synchronised with a digital signal source.
The `Lock` indicator is only used for SPDIF input sources.
The DAC is now ready to operate.
Reset
The DAC-10 / DAC-10 DSD is equipped with an SPDIF `reset` switch (non-latching), located on
the ack plate. Occasionally, the digital receiver may not lock onto the signal during the power
up cycle or hot swapping of digital input ca les. Should this occur, simply single press and
release the `reset` switch. This will restart the receiver’s automatic ‘signal locking’ procedure.
The reset switch has no function for USB inputs.

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Safety Information
Placement
Apart from the valves, which, y their very nature, are designed to run hot, the DAC-10 / DAC-
10 DSD is relatively cool running and operates well elow the maximum allowed temperature
for consumer audio.
It should e positioned so as to allow free airflow around it and not placed on top of other
equipment – particularly Class A amplifiers, which run hot.
Possi le vi rations should e minimised as far as possi le. For example, the DAC-10 / DAC-10
DSD must not e placed on top of speakers. Ideally, the unit should e placed in line with (or
slightly ehind) the plane of your speakers and additional enefits may e gained y placing it
on a good quality isolation platform.
Cleaning t e unit.
Always disconnect the power cord from the mains socket when cleaning or performing other
maintenance.
Tube replacement.
The front pair of matched valves can e replaced with the same type allowing users to tune the
sound slightly. Please contact VAD or your dealer for advice on replacements. Valve codes
6SN7, 6N8S, 1578, ECC32, CV1988, 6SN7GT, 5692, CV181 or other direct equivalent to 6SN7 are
compati le. Please note: The protective cover will not fit over the taller CV181 valves.
Use of any other valve type will damage the circuit and invalidate the warranty. In case of
“valve rolling”, the use of octal valve socket savers is strongly advisa le, as any damage to the
valve sockets caused y “valve rolling” is not covered y the warranty.
The matched pair of 6N6P should only e replaced with the same type or 6N30P.
The pair of CV574 rectifier valves can e replaced with the same type or 6C5S, EZ35 or 6X5GT
equivalents.
Only a VAD authorised service agent should replace the internal ECC84 HF valve.

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IMPORTANT:
Tube (valve) replacement
The DAC must e powered OFF y the mains switch on the ack panel (mains IEC socket) and
then fully disconnected from the mains socket for a minimum of 10 minutes efore
commencing any tu e replacement.
(` leeding` the circuit fully discharges power supplies within 2 minutes, ut take care as the
valves may e still too hot to handle).
Fuse
The unit is fitted with an Anti Surge 1A fuse, which is located in the IEC mains socket on the
ack panel – t is must be replaced only wit t e same amperage value! (a spare fuse is
provided in the fuse “drawer”). In case of su sequent fuse failure, the unit should to e sent to
an authorised VAD service agent for checking.
Eart connection
T e unit must be eart ed! This is provided y the safety earth contact in the IEC mains socket.
Make sure that the earth connection of your home mains electrical installation is in order.
Removing t e protective Valve Cover.
The valve cover is secured to the top of the unit y way of 4 hex olts eing accessi le through
slots in the valve cover. The cover may e removed in order to facilitate tu e replacement y
using the supplied long hex key (2mm) tool to undo the olts.
We do not recommend using DAC-10 / DAC-10 DSD without the protective cover – valves are
hot when operating.
DAC-10 / DAC-10 DSD valves operational `life span` information.
The DAC-10 / DAC-10 DSD has een designed to the highest parameters, with each component
rigorously tested. We have chosen to use NOS (New Old Stock) valves due to their audio
qualities and longevity. However, due to the nature of vacuum valves, we offer a 90 days from
purchase date warranty for the valves originally supplied for peace of mind.
`Burn-in` time.
Each DAC-10 / DAC-10 DSD is hand- uilt and then tested through for a minimum of 24 hours
` urn-in` test (all input sources, all output levels). This means that the DAC-10 / DAC-10 DSD
has a 24 hours urn-in period prior to delivery.
Once installed, we recommend a further 100 hours urn-in period for the DAC-10 / DAC-10
DSD to reach its full potential.

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Specifications
Audio Signal Frequency Range: 5Hz - 20 kHz (PCM)
5Hz - 30 kHz (DSD)
Dynamic range: 122dB
Digital inputs: 1x AES/EBU (DAC-10 only)
1x RCA Coaxial
1x BNC
1x Toslink optical
1x asynchronous 32 it/192kHz USB 2.0
PCM input
1x asynchronous USB 2.0 DSD input (DAC-
10 DSD only)
Output Signal Level (adjusta le via gain control): 50mV to 4.4Vrms (approximate)
Analogue Outputs: 1x XLR ( alanced) max. 4.5Vrms- adjusta le
1 xSingle ended RCA outputs 50mV to
4.4Vrms – adjusta le
Output impedance: <400ohms
Total correlated jitter (SPDIF): <30ps
Digital input word widths supported 16-24 it (SPDIF)
16-24-32 it (USB PCM)
Digital input sampling frequencies supported: All sample rates etween and including
32kHz-192kHz (PCM)
USB Audio 2.0:(DAC-10 PCM): 16-32 it/up to 192 kHz PCM
(DAC-10 DSD): PCM, DSD64
Thermionic valves used: 2x 6SN7 dual triode (or equivalent)
2x 6N6P dual triode (or equivalent)
2x CV574 full wave rectifier (or equivalent)
1x ECC84 HF dual triode (or equivalent)

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Power consumption: 58W
AC mains operation voltage: Factory set for 220-240V/50/60Hz
(100-120V/50/60Hz factory set version can e ordered at no additional cost)
Fuse type: 1A Anti Surge 20mm fuse
Dimensions: H 15cm x W 43.5cm x D 29cm
Net Weight (approximate): 13kg
Shipping weight (approximate) 18kg

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Valve Audio Devices (VAD)
DAC-10 / DAC-10 DSD
Warranty Information
Valve Audio Devices Limited warrants this product to e free from defects in materials and
workmanship for a period of seven (7) years from the date of purchase (su ject to the terms
set forth elow). Valve Audio Devices will repair or replace (at VAD option) this product or any
defective parts in this product within the warranty period. Warranty periods may vary from
country to country. If in dou t, consult your dealer and ensure that you retain proof of
purchase. To o tain warranty service, please contact the VAD authorized dealer from which
you purchased this product. If your dealer is not equipped to perform the repair of your VAD
product, it may e returned y you or your dealer to Valve Audio Devices or an alternative
authorized VAD service agent. You will need to ship this product in either its original packaging
or packaging affording an equal degree of protection.
To qualify for the full seven year warranty, the customer must return the Warranty Registration
Form (included as the last page of this manual) to Valve Audio Devices Limited within 30 days
of purchase.
Proof of purchase in the form of a ill of sale or receipted invoice, which acts as evidence that
this product is within the warranty period, must e presented to o tain under-warranty
service.
This Warranty is invalid if the factory-applied serial num er and/or Warranty sticker has een
altered or removed from this product. This Warranty is invalid if the proof of purchase cannot
e presented. A returned product must e accompanied y a written description of the defect.
Any c anges or modifications to t e product (apart from replacing t e tubes as directed in
t e user manual) will invalidate t e 7 year warranty
This Warranty does not cover cosmetic damage or damage due to acts of God, accident,
misuse, a use, negligence, commercial use, or modification of, or to any part of, the product.
This Warranty does not cover damage due to improper operation, maintenance or installation,
or attempted repair y anyone other than Valve Audio Devices or a VAD dealer, or authorized
service agent, which is authorized to carry out Valve Audio Devices warranty work. Any
unauthorized repairs will void this Warranty. This Warranty does not cover products sold AS IS
or WITH ALL FAULTS.

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REPAIRS OR REPLACEMENTS AS PROVIDED UNDER THIS WARRANTY ARE THE EXCLUSIVE
REMEDY OF THE CONSUMER. VALVE AUDIO DEVICES LIMITED (VAD) SHALL NOT BE LIABLE FOR
ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES FOR BREACH OF ANY EXPRESS OR IMPLIED
WARRANTY IN THIS PRODUCT. EXCEPT TO THE EXTENT PROHIBITED BY LAW, THIS WARRANTY
IS EXCLUSIVE AND IN LIEU OF ALL OTHER EXPRESS AND IMPLIED WARRANTIES WHATSOEVER
INCLUDING, BUT NOT LIMITED TO, THE WARRANTY OF MERCHANTABILITY AND FITNESS FOR A
PRACTICAL PURPOSE.
Some Countries and US states do not allow the exclusion or limitation of incidental or
consequential damages or implied warranties so the a ove exclusions may not apply to you.
This Warranty gives you specific legal rights, and you may have other statutory rights, which
vary from state to state or country to country.
For any service, in or out of warranty, please contact your dealer.
Valve Audio Devices reserves the right to modify the design of any product without o ligation
to purchasers of previously manufactured products and to change the prices or specifications
of any product without notice or o ligation to any person.
DAC-10 /DAC-10 DSD is a UK Patent Office international registered design.
Valve Audio Devices Limited
17 Ash y Road
Welton
DAVENTRY
NORTHAMPTONSHIRE
NN11 2JS
UNITED KINGDOM
Company No. 08298028
Copyright Valve Audio Devices Limited 2013

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Valve Audio Devices (VAD) Warranty Registration Form
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Title
Last Name:
Full address (number and street):
City:
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State/Province:
Country:
Phone Number:
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Date of Purchase (day/month/year):
Please indicate the serial number and warranty number of this product. (Found on the ID labels
attached to your product) .
S/N No. Warranty No.
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We will not share any of your information with other companies for any marketing purposes
If you do not wish us to send you VAD product updates, please mark this box
Please complete the form upon purchasing your product.
Detach and send it within 30days to:
Valve Audio Devices Limited,
17 Ashby Road, Welton, Daventry, Northamptonshire. NN11 2JS