Dacs HeadMaster User manual

S
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Distribution of high performance, innovative products | Own brand pro audio and
custom products | Cabling | Demonstration studio and mastering facilities |
Outstanding after sales service | Studio design and build | Acoustic consultancy
and treatment | Sound system design and installation | Distribution of high
performance, innovative products | Own brand pro audio and custom products |
Cabling | Demonstration studio and mastering facilities | Outstanding after sales
service | Studio design and build | Acoustic consultancy and treatment | Sound
system design and installation | Distribution of high performance, innovative
products | Own brand pro audio and custom products | Cabling | Demonstration
studio and mastering facilities | Outstanding after sales service | Studio design
and build | Acoustic consultancy and treatment | Sound system design and
installation | Distribution of high performance, innovative products | Own brand
pro audio and custom products | Cabling | Demonstration studio and mastering
facilities | Outstanding after sales service | Studio design and build | Acoustic
consultancy and treatment | Sound system design and installation | Distribution of
high performance, innovative products | Own brand pro audio and custom products
| Cabling | Demonstration studio and mastering facilities | Outstanding after sales
service | Studio design and build | Acoustic consultancy and treatment | Sound
systemt design and installation | Distribution of high performance, innovative
products | Own brand pro audio and custom products | Cabling | Demonstration
studio and mastering facilities | Outstanding after sales service | Studio design
and build | Acoustic consultancy and treatment | Sound system design and
installation | Distribution of high performance, innovative products | Own brand
pro audio and custom products | Cabling | Demonstration studio and mastering
facilities | Outstanding after sales service | Studio design and build | Acoustic
consultancy and treatment | Sound system design and installation | Distribution of
high performance, innovative products | Own brand pro audio and custom products
| Cabling | Demonstration studio and mastering facilities | Outstanding after sales
service | Studio design and build | Acoustic consultancy and treatment | Sound
system design and installation | Distribution of high performance, innovative
products | Own brand pro audio and custom products | Cabling | Demonstration
studio and mastering facilities | Outstanding after sales service | Studio design
and build | Acoustic consultancy and treatment | Sound system design and
installation | Distribution of high performance, innovative products | Own brand
pro audio and custom products | Cabling | Demonstration studio and mastering
facilities | Outstanding after sales service | Studio design and build | Acoustic
consultancy and treatment | Sound system design and installation | Distribution of
high performance, innovative products | Own brand pro audio and custom products
| Cabling | Demonstration studio and mastering facilities | Outstanding after sales
service | Studio design and build | Acoustic consultancy and treatment | Sound
system design and installation | Distribution of high performance, innovative
products | Own brand pro audio and custom products | Cabling | Demonstration
tudio design and build | Acoustic consultancy and treatment | Sound system
USER GUIDE
eadMaster
H
D-A Converter, Monitor Controller,
Reference Headphone Amplifier

Instructions for use and installation
Welcome
At DACS we are very pleased that you have chosen to purchase one of our products.
We take pride in our work and are sure that this Headmaster will give you years of
reliable service. If you have any suggestions or comments about this product please
call, fax, write or e-mail us with your thoughts. Thank you.
Introduction
The HeadMaster is a reference quality all in one monitoring station with 4 selectable
inputs (2 digital, 2 analogue), a variable output, switchable between two sets of
loudspeakers, a headphone output, and in addition a fixed level output from the D-A
converter.
The D-A converters are by Crookwood. They are a 192kHz 24bit converter. We use a
technology that produces a jitter free output, regardless of the condition of the
incoming signal. This also means that locking to different sample rates will be quick
(flicking between theAES and SPDIF inputs) and the performance the same.
The analogue inputs use DACS proprietary Clarity circuitry. This means very low
noise and low distortion, with immense detail and clarity, superb stereo imaging and
stability. These inputs are balanced on XLR and unbalanced on phono. The inputs
are selected on the front panel via stainless steel switches with an LED indicator.
This unit offers very high performance, with the Crookwood D-As performing in an
exemplary fashion, and DACS’ well respected analogue expertise creating some of
the best sounding headphone outputs available, and pristine feeds to your studio
monitors.
eadMaster
H
DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]

DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]
11. Input Select switches - use
these to select which inputs you
wish to monitor on your
headphones and/or loudspeakers
6. Volume control for
headphone outputs 7. Power switch
4.
balanced on XLR,
unbalanced on phono
Analogue inputs,
1. IEC inlet factory set to 240V.
For 110V supply, remove fuse
holder and rotate so that 100V
legend is on top/correct way up
2. Digital inputs - AES/EBU
on XLR and S/P DIF on
phono with Crookwood D-A
3. Fixed level balanced out (factory
preset to 0dBFS=18dBu)
Variable outs A and B
u
5.Headphone o tput -
Tip=Left,Ring=Right,
9. Volume control for
loudspeaker outputs
8. Speaker seelct
indication LEDs
10. Selector switch toggling
between speaker outputs A&B

Using the DACS Headmaster
Installation
1 Connecting the Power
The unit will accept 240 VAC and 110 VAC mains supplies. The IEC inlet’s fuse holder
is used as a selector as shown in Fig 2. The factory setting is for 240 VAC.
Figure 2
2 Digital Inputs
Connections
The AES/EBU input is on XLR. The S/P DIF input is on phono. The inputs both accept
sample rates from 32kHz to 200kHz.
3 Fixed Level Out and Variable Outs, Balanced
This fixed level signal is a direct out from the D-A converters. It is factory set to
provide a signal level of +18dBu for a digital signal at 0dBFS. For unbalanced
operation you must connect the output Pin 3 to Pin 1 OR connect the unbalanced
screen to Pin 3 (optionally leaving the Screen terminal of the TRS jack unconnected).
If an analogue input is selected but there is an AES/EBU signal coming in to the unit,
then this signal will appear on the fixed level output regardless of the analogue input
selected. If there is an S/P DIF signal coming in it will not be sent to the fixed level
output. However, if you wish the S/P DIF input to go to the fixed level output while an
analogue input is active, then this can be achieved by pressing the S/P DIF and the
analogue input simultaneously.
The variable outputs are intended to feed loudspeakers, and use two pairs of TRS
jack sockets. If the destination is unbalanced, then the output must be connected
either by using a two pole jack in the HeadMaster (or linking the Ring and Sleeve of a
TRS jack) or by connecting the signal to the Tip of the TRS jack and the unbalanced
screen to the Ring of the TRS jack (and optionally leaving the Screen terminal of the
TRS jack unconnected).
240V
110V
Set for 240VAC
240V
110V
Set for 110VAC
DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]

In either case the level feeding the unbalanced input will be the same as the
balanced signal level.
4 Analogue Inputs
There are two sets of analogue inputs: balanced on XLR and unbalanced on Phono.
The maximum input level for the balanced inputs is around 28dBu, and for the
unbalanced inputs is +11dBV.
5 Headphone Output
The headphone outputs are on three pole ¼” jack, tip=left, ring=right, sleeve=0V. The
front and rear sockets are connected in parallel. The output circuitry is designed to
drive down long lines with minimal high frequency loss. If you are sending
headphones signals down long lines using screened twin conductor cable (such as
foil screened twin, FST), we would recommend using two separate cables if you can.
This would reduce any possible cross-talk between the left and right channels. There
are installations we know of where left and right are sent down the two conductors in
a single cable, and all reports have been good.
If two or more pairs of headphones are to be driven by an output, they should be of
the same type and impedance. If they are different (eg. low and high impedance),
power sharing will not be even. One will be too quiet, and to achieve the required
level in that pair, the other pair will overload.
6 Volume Control for Headphone Outputs
This knob controls the volume of the headphone outputs; since both front and back
connections are in parallel it controls both outputs.
7 Power Switch
This switch illuminates when mains power ispresent. NB the switch is before the fuse
so if the mains switch is illuminated and none of the LEDs light up, then it may be that
the fuse is blown.
DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]
Note on the problems of Loudness and Headphones
Our amplifier cannot do the impossible! We can only make headphones as loud as
they are capable of being. Beyond that they distort and clip, which is very bad for your
ears, short and long term. The problem usually is not so much that the headphones
are not loud enough; it is more that the sounds outside are too loud and are breaking
through into your ears. Approached from this direction the problem can be solved
more easily.

8 Speaker select indication LEDs
These indicate which of the two pairs of balanced outputs,Aor B, are selected
9 Speaker volume control
This controls the volume of whichever speaker output is selected
10 Speaker selector switch
This switch toggles between the two speaker outputs; active output is indicated by
the speaker selection LEDs to the left of the speaker volume controls
11 Input select switches
These four switches select the input that will appear at the various outputs from this
device. The options are unbalanced analogue, balanced analogue, S/P DIF digital
andAES/EBU digital.
DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]

Specifications for Headmaster
For 1kHz sine in Direct Out Monitor Out HP Out
(into 150R)
THD + N 0.001330% 0.002700% 0.003500%
AES @ -18dBFS @0dBu out @-16dBu out @+3dBu out
THD + N / 0.001300% 0.003400%
Balanced IP @ 0dBu @-9dBu out @+10dBu out
THD + N / 0.003700% 0.004000%
Unbalanced IP @ -10dBV / @-16dBu out @+3dBu out
Maximum Input Balanced >+28dBu
Maximum Input Unbalanced 11dBV
Compliance to European Standards
This unit complies with the following standard (see Declaration of Conformity):
Radiated Emissions to Specification EN50081-1
Conducted Emissions to Specification EN50081-1
Electro Static Discharge to Specification EN50082-1
Fast Burst Transients to Specification EN50082-1
DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]

DACS’ range of high performance studio and stage devices embody our
philosophy. We believe in simplicity, but above all else, Clarity; sonic Clarity and
functional Clarity. The range includes the DACS MicAmp2, a two channel
microphone pre-amplifier¹ (see also reviews in Sound on Sound and Studio
Sound, both November 1997 viewable on our website). Our recently launched
(Aug 2006) Eightch, an eight channel volume control, won the Pro Audio Review
PAR Excellence award.
For many years DACS have manufactured custom equipment for
professionals the world over using a number of our own high performance audio
building block circuits. The performance of these circuits has been honed over
the years out in the field, and developed through fulfilling the changing
professional requirements of their many customers in widely divergent sectors of
the industry.
DACS have crystallised these years of experience to bring you this
range of elegantly simple high performance units, all hand made throughout.
Where they benefit performance we use expensive components and time
consuming processes, but do not spend prodigiously on ‘cosmetics’. Though we
are bucking the trend towards downsizing work-forces and automating
manufacturing processes, these units are very competitively priced. This is
achieved by a combination of good design, good organisation, low overheads,
and the use of standard housings and other components where possible.
These visually striking, well engineered devices will last well into this
century achieving levels of performance that digital technology, and much
analogue technology, aspires to today.
YOU are what make your studio world class.
Our equipment is designed to help you continue to produce fine music well
into this century.
¹ We are proud to announce that the MicAmp won the Studio Sound Audio Industry Recognition
Award in the Outboard Pre-amp category. This was voted for by registered readers of Studio Sound
worldwide.
Other Fine Hand Crafted Audio Products from DACS Ltd
Clarity from DACS Ltd
A new philosophy, a new range of devices
DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 OHW
Tel:[phone] | Fax: [phone] | www.dacs-audio.com | [email protected]