Dacs HEADLITE 3 User manual

USER GUIDE
HEADLITE 3

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 HEADLITE 3 will give you years of
exemplary 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
HEADLITE 3 is a four input, four output headphone amplifier, with a six position self
cleaning monitor select switch for each amplifier. It is designed to be as flexible as
possible without introducing needless complexities. Its THAT Ingenius balanced
input ensures very low distortion, transformer like rejection of interference, and very
good frequency response. The inputs are on three pole jack sockets, and will also
accept unbalanced signals on 2 pole jacks.
Its outputs are capable of driving virtually all headphones; we know of none it has
problems with. The outputs are also designed to drive down long lines to cubicles
with little or no loss of quality. The unit is compatible with -10dBV and +4dBu inputs
(see page 5 - “2 & 5 Inputs”).
For users who require each output to feed multiple headphones, we offer the Power
modification, which significantly increases the power output. The Power modification
is fitted to Output 1 as standard but can be fitted to two, three or all four channels of
HEADLITE 3. It is a transistor amplifier with built-in limiting (soft clip) to help protect
low impedance headphones from burn out. It will allow a number of high impedance
headphones to be powered from the same output without a loss of signal level at the
headphones;
Additional power modifications can be retrofitted any time after purchase. Please
speak to your retailer or direct to us for details.
®
we’ve used up to 6 pairs of 400 Ohm headphones on one output and
experienced no level drop.
HEADLITE 3
DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]

10. Power Switch
8. Input Select switch - use
this to select which
combination of inputs you
wish to monitor on your
7. Volume control for
headphone outputs
6. Headphone ouputs for
engineer or performers in
control room
4. Audio 0V, isolated
from mains earth
1. IEC inlet factory set to 240V.
For 110V supply, remove fuse
holder and rotate so that 115V
legend is on top/correct way up
2. Four headphones inputs
patchbay or direct from console; use 2 pole
jacks for unbalanced version or 3 pole for
balanced version NB balanced version will also
accept 2 pole jacks/unbalanced inputs
wired from
3. Four headphone outputs; can
be hard hard wired to booths,
recording areas etc
.Setivi y sw t hs
5nsi t ic
for ch elann sA&B
and C&D
9. Input level meters
DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]

Using the DACS HeadLite2
Installation
1 Connecting the Power
The unit will accept 240 VAC and 110/115 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
240V
110V
Set for 240VAC
240V
110V
Set for 110VAC
Remember that for headphone feeds, the screen must be connected
at both ends of the cable.
DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]
2 & 5 Inputs
Connections
Inputs A, B, C and D are on three pole ¼” jack sockets,
sleeve=0V). Unbalanced signals may be used on two pole jacks. The input
impedance is 10k ohms.
If no connector is plugged in, the inputs are shorted to 0V via the switch connections
on the jacks. If the inputs are connected to a patchbay, it is advisable, if possible, to
normalise them. Do this at the patch bay. If they are not normalised and are left
floating, they may be prone to pick up interference, taxis or the radio over long lines
between the unit and the patchbay.
Levels
The input buffer’s sensitivity can be adjusted for +4dBu or -10dBV operation using
the switches. Note: Channel A & B sensitivity are selected by one switch and
Channel C & D sensitivity by the other. It is not possible to select different
sensitivities for each one of the paired channels.
tip=+/Hot, ring=-/Cold and

DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]
3 & 6 Outputs
Connections
The headphone outputs are on three pole ¼” jack, tip=left, ring=right, sleeve=0V. The
front and rear outputs for each headphone amplifier 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 of FST, 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.
4 Earthing
The signal 0V is separate from the mains earth. This separation allows unbalanced
operation with a large measure of immunity to hum problems, since the amplifier is
not referenced to or connected to any earth other than the signal source. The mains
earth is connected to the case of the device. If you wish to connect the signal earth to
the mains earth or a technical earth, this may be done by running a wire from the
earth tag. This connection should only be made by qualified personnel, if it is
necessary. If in doubt please call us.
5 Sensitivity Switches
On the rear panel, there are sensitivity switches for channels A&B and C&D.
This allows user selection of sensitivity as an operational control, rather than
having to be set with internal links.
7 Volume Control
The HEADPHONE VOLUME control adjusts the signal level going to the amplifier.
This control allows independent volume control of each amplifier’s output.

DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]
8 Input Select switch
With up to four inputs connected to the unit, you can decide which headphone
amplifier output you wish to use. To select the input(s) you wish to listen to, rotate the
selector switch to the appropriate point: AB means inputs A and B on the Left and
Right output channel respectively;, AA means input A on both Left and Right, etc.
Plug your headphones in and adjust the volume to an acceptable level.
9 Input Meters
These tri colour LED meters indicate the level on the 4 busses feeding the
headphone amplifiers. They are calibrated as follows:
Green starts to glow at -24duB and is fully on at -8dBu to 0dBu
Orange starts at 0dBu and is fully on at +10dBu to +16dBu
Red starts at +16dBu and is fully on over +18dBu
For optimum performance operate HEADLITE 3 at 0dBu to +16dBu.
10 Power
This switches the power on and off, and is illuminated whenAC mains is present. The
switch is connected before the fuse, so if the switch is illuminated and the unit does
not work, the fuse may be blown. The unit comes with a spare fuse in the fuse carrier
(T1A).
Clarity HEADLITE 3 is fitted with the ultra quiet regulated linear power supply as used
in the DACS Clarity MicAmp.

Specifications for DACS’ Clarity HEADLITE 3
Noise floor: <-90dBu (110dB below peak)
Dynamic range: >114dB
THD+N 20Hz to 22kHz, +10dBu into 600R <.00045%
Frequency response: 5Hz to 40kHz ± .5dB
Slew rate: Greater than required for 40kHz
Settling time to 0.1%: this will depend on the load to a great extent,but very good
Max phase rotation (inter channel phase difference): 100Hz .01 deg, 1kHz .03 deg,
10kHz .36 deg, 20kHz .72 deg
Crosstalk: <-90dB
Power output >200mW/ch into 600R
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]
Levels
The amplifier section can deliver up to 0.5W RMS per channel and has a fixed gain of
20dB. The volume potentiometer varies the input level to the amplifier stage. Too
high an input level here will reduce the useful control over the output volume, since it
will have to be set very low to ensure that the output does not clip. To adjust this level
see below - 2 & 8 Inputs.
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 perhaps be solved more easily.

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 Clarity MicAmp2, a two
channel microphone amplifier (see also reviews on our website) and the DACS
Clarity HeadMaster, a stereo monitor controller.
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 the
21st 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.
Other Fine Hand Crafted Audio Products from DACS
Clarity from DACS
A new philosophy, a new range of devices
DACS LTD, Stonehills, Shields Road, PELAW, Gateshead, Tyne and Wear NE10 0HW
Tel: [phone] | Fax: [phone] | www.dacs-audio.com | [email protected]