HA1M SIGNATURE SERIES User manual

HA1M
Two Input Headphone Amplifier
Two mono inputs to one stereo headphone amp
User Guide
Glensound
6 Brooks Place, Maidstone
Kent, UK, ME14 1HE
Tel: [phone]
www.glensound.co.uk

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Glensound Electronics Ltd
Thank you for choosing a new Glensound product.
All rights reserved.
Information contained in this manual is subject to change without notice, if in
doubt please contact us for the latest product information.
If you need any help with the product then we can be contacted at:
Glensound lectronics Ltd
1 – 6 Brooks Place
Maidstone
Kent
M 14 1H
United Kingdom
Telephone: [phone]
Fax: [phone]
MAIL ADDR SS S
General enquires: [e-mail]
Technical enquires: [e-mail]
Sales enquires: [e-mail]

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IMPORTANT SAFETY INSTRUCTIONS
1) Read these instructions
2) Keep these instructions
3) Heed all warnings
4) Follow all instructions
5) Do not use this apparatus near water
6) Clean only with a dry cloth
7) Do not block any ventilation openings. Install in accordance with manufacturer s
instructions
8) Do not install near any heat sources such as radiators, heat registers, stoves, or other
apparatus (including amplifiers) that produce heat
9) Do not defeat the safety purpose of the polarized or grounding type plug. A polarized plug
has 2 blades with one wider than the other. A grounding type plug has 2 blades and third
grounding prong. The wider blade or the 3
rd
prong are provided for your safety. If the
provided plug does not fit into your outlet, consult an electrician for replacement of the
obsolete outlet
10) Protect the power cord from being walked on or pinched, particularly at plugs,
convenience receptacles and the point where they exit from the apparatus
11) Only use attachments/ accessories specified/ supplied by the manufacturer
12) Use only with the cart, stand, tripod, bracket, or table specified by the
manufacturer, or sold with the apparatus. When a cart is used, use caution when moving
the cart/ apparatus combination to avoid injury from tip over
13) Unplug tis apparatus during lightning storms or when unused for long periods of time
14) Refer all servicing to qualified service personnel. Servicing is required when the apparatus
has been damaged in any way, such as power supply cord or plug is damaged, liquid has
been spilled or objects have fallen into the apparatus, the apparatus has been exposed to
rain or moisture, does not operate normally, or has been dropped
15) Do not attempt to modify this product. Doing so could result in personal injury and/ or
product failure
This symbol is intended to warn that
dangerous voltages within the product are
present and constitute a risk of electric
shock.
This symbol is intended to highlight that
there are important operating &
maintenance instructions in the literature
accompanying this unit.

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IMPORTANT: MAINS PLUG WIRING INSTRUCTIONS
This Signature unit is supplied with a moulded mains plug fitted to the AC mains
lead.
Mains wiring colours/ connections
The Green/ Yellow or Green wire must be connected to the terminal in the plug
marked ‘E’ or with the Earth Symbol.
The Blue or Black wire must be connected to the terminal in the plug marked ‘N’
(Neutral).
The Red or Brown wire must be connected to the terminal in the plug marked ‘L’
(Live).
THIS UNIT MUST BE EARTHED
THIS UNIT IS FITTED WITH AN INTERNAL MAINS FUSE.
The fuse is located internally between the Live terminal of the IEC plug and the
Live input of the power supply. The fuse should only be changed by a qualified
service engineer. If replacing the fuse care should be taken to fit a correctly rated
replacement. The fuse rating can be found in the technical specifications page of
this handbook.

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CE
This equipment manufactured by Glensound lectronics Ltd of Brooks Place
Maidstone Kent M 14 1H is CE marked and conforms to:
Low Voltage Directive: N60065
missions: N55103.1
Immunity: N55103.2
WASTE ELECTRICAL AND ELECTRONIC EQUIPMENT
REGULATIONS 2006 (WEEE)
Glensound lectronics Ltd is registered for business to business sales of W in
the UK our registration number is:
W /JJ0074UR
RoHS2 DIRECTIVE
C directive 2011/65/ U restricts the use of the hazardous substances listed below
in electrical and electronic equipment.
This product conforms to the above directive and for this purposes, the maximum
concentration values of the restricted substances by weight in homogenous
materials are:
Lead
0.1%
Mercury
0.1%
Hexavalent Chromium
0.1%
Polybrominated Biphenyls
0.1%
Pol
ybrominated Diphenyl thers
0.1%
Cadmium
0.01%

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PRODUCT WARRANTY:
All equipment is fully tested before dispatch and carefully designed to provide you
with trouble free use for many years.
We have a policy of supporting products for as long as possible and guarantee to
be able to support your product for a minimum of 10 years.
For a period of one year after the goods have been despatched the Company will
guarantee the goods against any defect developing after proper use providing
such defects arise solely from faulty materials or workmanship and that the
Customer shall return the goods to the Company’s works or their local dealer.
All non-wear parts are guaranteed for 2 years after despatch and any defect
developing after proper use from faulty materials or workmanship will be repaired
under this warranty providing the Customer returns the goods to the Company's
works or their local dealer.

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HA1M Headphone Amplifier
Handbook Contents
Issue 1,
Description Page No.
Contents
IMPORTANT SAFETY INSTRUCTIONS ........................................................................................................................ 3
PRODUCT WARRANTY: ...................................................................................................................................................... 6
OVERVIEW .......................................................................................................................................................................... 8
PHYSICAL INSTALLATION ................................................................................................................................................. 9
AUDIO BLOCK DIAGRAM ................................................................................................................................................ 11
EXAMPLES OF USE ........................................................................................................................................................... 12
1. Presenter Programme Cue Monitor ....................................................................................................................... 12
2. Stereo Programme Monitor ....................................................................................................................................... 13
FRONT PANEL USER CONTROLS & CONNECTIONS ....................................................................................................... 14
1. 3.5mm Headphone Jack Socket ................................................................................................................................. 14
2. Left Volume Control ................................................................................................................................................. 14
3. Right Volume Control ............................................................................................................................................... 14
4. Power on Indicator .................................................................................................................................................... 14
5. 6.35mm (1/4”) Headphone Jack Socket .................................................................................................................... 14
6. Mono Switch ............................................................................................................................................................. 15
REAR PANEL CONNECTIONS ........................................................................................................................................... 16
7. Left Audio Input ........................................................................................................................................................ 16
8. Mix Output ................................................................................................................................................................ 16
9. +/-12VDC Input ........................................................................................................................................................ 16
10. Right Audio Input.................................................................................................................................................... 16
11. Mains Input ............................................................................................................................................................. 16
WIRING INFORMATION ................................................................................................................................................... 17
1. Standard wiring info .................................................................................................................................................. 17
2. Connecting to unbalanced devices ............................................................................................................................ 18
SPECIFICATION ................................................................................................................................................................ 19

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OVERVIEW
The Glensound Signature Series A1M is a professional two mono input headphone
amplifier. It is manufactured using high quality components and low noise audio circuits to
provide many years of trouble free use.
Although traditionally a broadcast manufacturer, Glensound’s products are equally at home
in professional and high end home studios, industrial installations and live pro sound
environments. The A1M can therefore be used in a number of applications.
It features two electronically balanced mono inputs on Neutrik XLRs each with its own front
panel gain control, one advanced signature stereo headphone amplifier and one
electronically balanced ‘mix’ output. The advanced signature headphone amplifier features a
unique facility which provides consistent audio output levels into both high and low
impedance headphones. This advanced stereo headphone amplifier can also automatically
accept mono headphone jacks meaning that mono earpieces can be used directly without
needing to re-wire cables.
It is possible to connect the balanced audio inputs & outputs to domestic style unbalanced
audio circuits and the preset gain controls provide sufficient output level adjustment to allow
this.
For added flexibility the A1M has a front panel ‘mono’ switch. Using this switch mixes both
the left and right inputs together and then sends the mono mix to both left and right outputs
of the stereo headphone amplifier.
The A1M is powered from an internal switch mode mains power supply fed from a filtered
IEC mains plug suitable for use Worldwide. It has an internal fuse for safety. The unit can also
alternatively be powered from an external +/-12V DC power source (such as the Signature
Series PS1). If both mains and external DC power sources are present then, if one power
source were to fail the unit would continue to work seemlessly from the other source.

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PHYSICAL INSTALLATION
The Glensound Signature Series have been designed to be highly versatile for installation and
can be installed in 19” racks with either their front or rear panels facing the front of the rack.
They can also be mounted underneath desks or work tops and can be either permananetly
mounted or stood (using the supplied feet) on top of desks or worktops.
INSTALLING SIGNATURE SERIES IN A 19” RACK
Firmly hold the signature subrack within the 19” rack and locate in 1RU of space. Use the
supplied 6mm rack screws to securly attach the unit to the rack.
INSTALLING ADHESIVE FEET FOR NON PERMANENT TABLE TOP MOUNTING
Remove the front rack ears (if they are not required), turn the unit upside down and attach
the supplied 4 adhesive feet as per the above drawing.
Signature
g
Series
Keeps Working
PWR ON
PART No
CE
W
50/60Hz 2.7 Watts
100-240V
+/-12V - - -
PIN 1 = GND
PIN 3 = -12V (100mA)
PIN 2 = +12V (100mA)
Top

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SWAPPING RACK EARS TO ALLOW THE REAR TO BE INSTALLED AT THE FRONT OF A
RACK
First remove the 4 silver button head screws that fix the rack ears onto the front of the unit as
shown in the top picture above.
Remove the rack ears and turn the unit around for access to its back panel.
Re-fit the 2 rack ears using the same 4 silver button head screws that were removed from the
front as per the bottom picture above.
USING THE MOUNTING HOLES FOR PERMANENTLY ATTACHING THE UNIT ABOVE OR
BELOW A WORKTOP/ DESK
Use either the top or bottom mounting holes as indicated above to use suitable screws to
attach the signature unit to a worktop or bench. **PLEASE ENSURE T AT YOU USE SUITABLE
FIXINGS**
Series
Signature
g
K eep s Wo rkin g
PWR ON
PART No
CE
W
50/60Hz 2.7 Watts
100-240V
+/-12V - - -
PIN 1 = GND
PIN 3 = -12V (100mA)
PIN 2 = +12V (100mA)
Series
Signature
g
Keeps Working
PART No
PWR ON

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AUDIO BLOCK DIAGRAM
LEFT IN
RIGHT IN
MIX OUT
6.35mm Headphone Jack Socket
3.5mm Headphone Jack Socket
Mono S itch
(Sho n in Mono Position)
Tip
Ring
Ring
Tip
NOTE:
Both jack socket sleeves are
connected to ground
Po er On
100 - 240 VAC
INTERNAL
FUSE
AC/DC PSU +12V
-12V
EXT DC +/-12V

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EXAMPLES OF USE
1. Presenter Programme & Cue Monitor
Mono Programme
Control Room Monitor
Headphones
or Earpiece
1 x XLR3
(balanced or
unbalanced)
1 x XLR3
MIX OUTPUT
Talkback Cue
1 x XLR3
(balanced or
unbalanced)
An On Air presenter either in TV or Radio will often be required to take cue feeds from a
director or producer and simultaneously monitor the programme audio.
In this situation both the mono programme and mono talkback cue feeds are fed into the
A1M, one source into the left input and the other into the right input. The presenters’ stereo
headphones are connected via the front panel headphone socket and the individual input
level controls allow the presenter to adjust the volume that he/ she monitors each of the 2
sources. In this case the presenter would monitor cue in one ear and programme in the other.
If the front panel mono switch was operated then the presenter would hear both cue and
programme in both ears.
An alternative but similar scenario would be if the presenter was using a mono earpiece
instead of stereo headphones. In this case the front panel mono switch would need to be on.
Because the A1M has sophisticated headphone amplifier circuits it is quite safe to connect
the mono earpiece jack to either of the front panel headphone sockets on the A1M.
In both of the above examples the line level mix output on the rear of the A1M could be
used for feeding an auxiliary monitoring position in a control room.

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2. Stereo Programme Monitor
Left Programme
Control Room Monitor
Headphones
or Earpiece
1 x XLR3
(balanced or
unbalanced)
1 x XLR3
MIX OUTPUT
Right Programme
1 x XLR3
(balanced or
unbalanced)
A fairly common requirement for TV, Radio & pro sound environments is for an operator/
presenter to monitor a stereo audio feed.
The A1M has 2 audio inputs so allows the monitoring of a stereo programme/ audio feed
from the internal headphone amplifier with the ability to individually adjust the volume/ level
of the left and right stereo inputs.
In this scenario the left and right audio inputs would be connected on the 2 rear panel XLR
audio inputs and the operators’ headphones (or earpiece) would be plugged into either the
6.35mm or 3.5mm front panel jack sockets.
The mono mix output would allow a control room loudspeaker or another headphone
amplifier to monitor the same audio mix as the operator.

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1. 3.5mm
eadphone Jack socket
FRONT PANEL USER CONTROLS & CONNECTIONS
1. 3.5mm Headphone Jack Socket
This is the output of the headphone amplifier presented on a standard 3.5mm TRS (tip Ring
Sleeve) jack socket. It is driven from separate output amplifiers to the 6.35mm headphone
output so different impedance headphones can safely be used on each output. Although the
A1M is a stereo headphone amplifier mono earpieces/ single ear headphones with mono
jacks can safely be used.
2. Left olume Control
This rotary potentiometer adjusts the audio level (volume) of the left input to the headphone
amplifier. Turning it clockwise increases the level and anti-clockwise decreases the level.
3. Right olume Control
This rotary potentiometer adjusts the audio level (volume) of the right input to the
headphone amplifier. Turning it clockwise increases the level and anti-clockwise decreases
the level.
4. Power on Indicator
When on this bright blue LED indicates that power is applied and the A1M is on.
5. 6.35mm (1/4”) Headphone Jack Socket
This is the output of the headphone amplifier presented on a standard 6.35mm TRS (tip Ring
Sleeve) jack socket. It is driven from separate output amplifiers to the 3.5mm headphone
output so different impedance headphones can safely be used on each output. Although the
A1M is a stereo headphone amplifier mono earpieces/ single ear headphones with mono
jacks can safely be used.
2. Left Ear Volume
Control
4.
Power
on indicator
5. 6.35mm (1/4”)
eadphone Jack socket
6. ‘Mono’ Switch
When on left & right
inputs appear on left &
right headphone
outputs.
3. Right Ear
Volume

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6. Mono Switch
When in the ‘up’ position this switch sets the headphone amplifier to work as a standard
stereo headphone amplifier where the left audio input is routed to the left headphone output
and the right audio input is routed to the right headphone output.
When in the ‘down’ position marked ‘mono’ this switch mixes the left and right audio inputs
together and then routes this mono mix to both the left and right headphone outputs.

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REAR PANEL CONNECTIONS
7. Left Audio Input
This standard 3 pin XLR provides an electronically balanced line level audio input to the
headphone amps left audio channel. This input can be wired unbalanced if required.
8. Mix Output
This audio output is a line level electronically balanced (can be wired unbalanced) output. The
audio output is a mono mix of the audio that is being sent to the headphones and it is
affected by the positions of the left and right volume controls.
9. +/-12 DC Input
This DC input can be used to power the A1M from an external DC source (such as the
Signature PS1). If both a DC input and a Mains input are present then the 2 power sources will
provide redundancy and if one fails the other will automatically take over.
10. Right Audio Input
This standard 3 pin XLR provides an electronically balanced line level audio input to the
headphone amps right audio channel. This input can be wired unbalanced if required.
11. Mains Input
This wide voltage range mains input (100 – 240 VAC) can be used to power the A1M. If both
a Mains & DC input are present then the 2 power sources will provide redundancy and if one
fails the other will automatically take over.
9
.
+/
-
12V DC Input
11. Mains Input
100
-
240VAC
8. Mix Output
Mono mix out of left
& right inputs
10. Right Audio Input
(0dB Balanced)
7. Left Audio Input
(0dB Balanced)

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WIRING INFORMATION
1. Standard wiring info
HEADPHONE WIRING NOTE:
The Signature Series range of products feature sophisticated headphone amplifiers whose stereo
outputs can be connected directly to mono headphone jacks without damaging the headphone
internal amplifiers.
12
3
XLR SOCKET (FEMALE)
1 2
3
XLR PLUG (MALE)
TIP
RING
SLEEVE
STANDARD XLR AUDIO PINOUTS:
1: Ground/ Earth
2: INPHASE/ POSITIVE/ MIC
3: MATE/ NEGATIVE/ MIC -
STANDARD HEADPHONE WIRING
:
TIP: A/ LEFT Ear
RING: B/ RIGHT Ear
SLEEVE: Common/ Earth

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2. Connecting to unbalanced devices
The input & output circuits of the Signature Series can be connected to unbalanced (domestic
style) devices. The wiring diagrams below show a mono jack plug as the unbalanced end of
the cable but this of course could easily be a different type of connector such as an RCA
Phono or ‘D’ type connector.
TO TIP
TO SLEEVE
TO TIP
TO SLEEVE
BALANCED OUTPUT
ON SIGNATURE UNIT
UNBALANCED INPUT
OF EXTERNAL DEVICE
BALANCED INPUT
ON SIGNATURE UNIT UNBALANCED OUTPUT
OF EXTERNAL DEVICE
12
3
21
3TIP
SLEEVE
TIP
SLEEVE

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SPECIFICATION
FEATURES
POWER
AUDIO HEADPHONES
PHYSICAL
Mains Input
Size
Internal Mains Fuse
Shipping Weight
DC Input
Mechanics
AC Consumption
Weight
Shipping Carton
Filtered IEC, 100 to 240VAC
47 - 63Hz
336 x 123 x 44mm (LxDxH) o rack ears
482mm 19” (1RU) with rack ears
20mm 1A A ti Surge
2.35kg
4 Pi Neutrik XLR plug +/- 12V
All alumi ium co structio , a odized a d
laser etched
1.5 Watts @ 230VAC
0.94kg
Rugged export quality cardboard carto
610 x 420 x 130mm LxDxH
Frequency Response
Distortion
Output Type
Maximum Output evel
Noise
>-2dB 20Hz to 20kHz
<0.015% THD @ 100Hz & 10kHz
Refere ce to +8dBu output
Sophisticated Electro ically bala ced
ca accept mo o or stereo jacks a d
automatic level correctio for low or high
impeda ce headpho es
+20dB i to 1KOhms +7dB i to 32Ohms
>-89dB @ li e up u weighted
RMS (22Hz to 22kHz)
Headphone Impedance
32 - 1000 Ohms
AUDIO MIX OUT
Frequency Response
Distortion
Output Type
Maximum Output evel
Noise
>-2dB 20Hz to 20kHz
<0.02% THD @ 100Hz, 1kHz & 10kHz
Refere ce to +8dBu output
Electro ically bala ced ca be wired
u bala ced
+24dBu
>-90dB @ li e up u weighted
RMS (22Hz to 22kHz)
Output Impedance
50 Ohms
Crosstalk
>-85dB @ 1kOhms >-55dB @ 32 Ohms
AUDIO GENERAL
Maximum Input evel
+20dBu
Front Panel Pot Gain Range
-70dB to +10dB