Page 1
2 plifier is going to be housed in an enclosed envi-
ronment, that you allow for adequate ventilation.
Despite the adequately sized heatsinks built into
the amplifier, it is still important that good ventila-
tion be provided. Do not install the amplifier di-
rectly above another heat generating component
such as another amplifier without adequate venti-
lation.
2. If your amplifier is going to be placed in an en-
closed space such as an armoire, it is essential that
adequate ventilation be provided.
3. The dealership from which you purchased the
product is an expert on custom installation proce-
dures and can provide invaluable advice to help
you make an aesthetically pleasing and trouble free
installation.
Caution For Connections
1. Connect this equipment only to the type of AC
power source as marked on the unit. Always route
AC power cords so they are not likely to be walked
on, or tripped over, or where they may be pinched
by items placed on or against them. Always pay
particular attention to cords at plugs and/or conve-
nience receptacles, and at the point where they exit
from the product.
2. Do not defeat the inherent design features of the
polarized plug. Non-polarized line cord adapters
will defeat the safety provided by the polarized AC
plug. If the plug should fail to fit, contact your
electrician to replace your obsolete outlet. Do not
defeat the safety purpose of the grounding-type
plug. If you use this product in a country which
only has two slotted receptacles in the house, you
must use a three-pin adapter plug to earth ground
which is the E (earth pin) of the power cord con-
nected to this product.
3. Do not overload wall outlets, extension or inte-
gral convenience receptacles, as this could result
in a risk of fire or shock.
Operating Voltage
The LDS2/75 amplifier is factory-set for 110V,
120V or 230V AC operation at either 50 or 60 Hz,
according to the country for which the unit was
manufactured (230V in European Union countries,
in compliance with CE regulations). The operat-
ing voltage cannot be changed by the user and any
attempt to do so will void the warranty.
Care of the Product
Clean the product by dusting with a dry cloth. Donot permit objects of any kind to be pushed and/or
fall into the product through the enclosure open-
ings.
General Description
The LDS2/75 is an intuitive product that has been
designed to provide amplification for up to two
pairs of 8 ohm speakers or one pair of 4 ohm speak-
ers.
The LDS2/75 outputs a total of 100 watts into 8
ohm loads and 150 watts into 4 ohm loads. An
embedded MPU (Micro Processing Unit) ensures
that the amplifier cannot be overdriven, and the
LDS (Load Detection System) ensures that all
speaker connections must be good before the am-
plifier is connected to the speakers.
The LDS2/75 has an automatic internal sub-sonic
filter of -18dB per octave which rolls off very low
frequency content (below 20 Hz) to avoid low fre-
quency saturation of a transformer volume control.
The unit can be set for a bridged/mono application
in which case the output will be 150 watts into 8
ohm loads.
The 2/75 has a great many features all of which are
described in this manual.
Front Panel Description
The front panel has a blue LED will glow brightly
when the unit is active and will dim considerably
whenever the unit is in its sleep mode.
The volume control knob allows you to set a pre-
ferred level.
Rear Panel Description
The following description identifies each of the
main controls/connection options and follows the
rear panel from left to right.
Input
The amplifier offers both speaker level and line
level inputs. A balanced input buffer is employed
in the speaker level input circuit that will accept
an output signal from either a grounded or a float-
ing music source.
Line Output (Buffered)
For use whenever a daisy-chain installation and
multiple LDS2/75s are used.
Mode Switch
This control allows for a selection of Stereo
Page 2
3 Mono or Mono/Bridged. In the latter mode, the
maximum output power is 150 watts. Please note
that R-Channel input is accepted under the
bridged operation. Bridging is
ONL Y recom-
mended when 8 Ohm speakers (or greater imped-
ance) are used.
Music
With the LDS2/75s trigger switch in the music
position, it will automatically function once it re-
ceives a music signal and will move into its standby
mode whenever the signal is absent for approxi-
mately five minutes. It will reactivate immediately
a signal is again received.
12 Volt Trigger
With the switch in the 12V position, the LDS2/75
can be turned on from a standby state whenever a
6V to 15V input signal appears at the 12V input
connector.
12 Volt Connector
For 12V trigger input and output use the upper two
circuits marked +IN- for 12V trigger input (to turn
on the LDS2/75 amplifier) and use the lower two
circuits marked -Out+ for trigger output. The in-
put accepts only a continuous DC trigger signal
from 6V minimum to 15V maximum for turning
on the LDS2/75 amplifier.
The trigger output is capable of delivering a con-
tinuous 12V, 30 mA of DC current to drive the
down-stream products (or multiple units of LDS2/
75 amplifiers) that may be associated with the
LDS2/75 amplifier.NOTE: If the music is discontinued for longer
than 5 minutes, the LDS2/75 will automatically
enter its sleep mode to cut down on energy con-
sumption. The front blue LED will then dim to
indicate that the amplifier is in Sleep and will
only return to its full luminance when it again
receives a music signal.
LDS LED
This important control indicator is provided to in-
dicate the correctness of your speaker connections
and to indicate that the intended speaker load is
not too great for the amplifier.
Speakers 1 and 2
These are the speaker-out terminals that are con-
nected with the cables from the loudspeakers.
Power Switch
Normally once you have switched on the amplifier
the signal sensing mode or the 12 volt trigger switch
will ensure that the amplifier goes into a sleep/
standby mode whenever it is not being directly
used.
Protection Features
Your LDS2/75 includes some important circuits
that are designed to protect the amplifier.
LDS (Load Detection System)
The LDS feature is a patent pending circuit that
prevents bad speaker connections to be made that
could cause the amplifier to short.
Fig. 2. Rear panel view
LINE SPEAKER
INPUT
L
R
LINE
OUTPUT
(BUFFERED)
LEVEL
LO HILDS LED
SEE
BELOW
12 SPEAKERS
L
R
+ +
12V POWER
120V 60Hz 3A
275
TECHNOLOGIES, INC.Sherbourn
STEREO
BRDG MONOMODE
OUTIN+ +
L
R
+
+
MUSIC TRIGGER
VOLUME
MIN MAX
POWER
Sherbour n
Fig. 1. Front panel view
