Keene KLAB20DB Product Data Sheet
Installation & Connection
Installation should only be carried out by a qualified installer or electrician, as a certain amount of
electrical knowledge is assumed.
Mounting
The 25mm depth will allow installation into standard UK 2-gang boxes, which may be galvanised
metal for installation in solid walls, or plastic drylining (with lugs) or surface mount box or trunking
system.
Wiring
In order to make a reliable and safe connection without short circuits it is recommended that the
speaker cables and line input signal cables are prepared and tinned prior to connection, with no
more than ¼” or about 7mm of tinned wire extending out of the insulation.
Power
The amplifier requires a power supply of 12v to 18v DC centre positive and a minimum current of
3500mA. If you are not using the recommended psu please verify that the supply is correct BEFORE
connection. If using the recommended supply we suggest that it is connected in accordance with
current wiring regulations. The amplifier can also be powered from a 12v car battery but NOT directly from a car battery charger as this would damage the circuitry. Do not install near any heat
sources such as radiators, stoves, or other apparatus that produce heat. The mains connection
should be via a fused and switched mains outlet such as order code SWL1.
Environment
The KLAB20DB is not IP rated for use in a damp environments but if due care is given to positioning
of the amplifier and supply then it can be used in zone 3 installations. Please use a qualified electrician operating to current regulations if you intend to use this unit in a bathroom.
Overview
The Keene KLAB20DB is a compact, powerful stereo
amplifier built onto a standard size UK double gang
wall plate. It provides 20W (RMS per channel) of
amplification eliminating the need to make space for a
conventional amplifier. It draws it’s own power from an
externally located mains adaptor and can be
controlled by push buttons integrated into the front
panel membrane and also by infra red remote. It can
be switched between four audio sources; an
integrated FM radio, rear line inputs, bluetooth and a
front panel 3.5mm jack input. The amplifier uses class
D digital circuitry for maximum efficiency and
generates very little heat. The amplifier only requires
25mm depth and so may be either flush or surface mounted.
IMPORTANT - Please Read!!!
The front panel membrane has two tabs that can be flexed outward
to allow access to the panel fixing screws. Once fastened in position
and tested the backing paper can be peeled off and the tabs fixed
down flush to conceal the screws. ONLY
perform this operation
once the installation has been tested and found to be satisfactory.
Once stuck down these tabs cannot be removed without damage to
the front panel.
Replacement front panels are available, (part number KLAB20DBFP)
Loudspeakers
Connect the loudspeakers being careful to keep both left and right phase connections the same. For exampl e
if you’ve connected the left speaker positive to “A” and negative to “B” make sure that the right speaker
positive also goes to “A” and negative to “B”. Please note that the amplifier is fully bridged so there is NOT a
common ground or return connection. The recommended minimum speaker impedance is 4 ohms on each
channel. If driving 2 speakers or more on each channel use them in series if they are both 4 ohms or in
parallel if they are both 8 ohms. Note the speaker corresponding to the left input is actually on the right hand
terminals in the amp as viewed from the front.
Line input
Connect the input signal cables using tinned screened cable. Connect the screens to the 2 centre connections
and the 2 signal wires (centre cores) to the top and bottom connectors. Note all the connectors are of the
superior rising clamp style so that they make a sound connection without biting through the copper of the
cable.
Aerial
The FM radio requires a 75ohm aerial for operation. The bare wire ends of the supplied aerial cable should be
connected to the terminals on the PCB and the other end arranged in a "T" shape as best as possibl e within
wall or ceiling. If the cable needs to be extended then use similar sized 75ohm impeda nce cable. If you wish
to connect to an external FM loop aerial then use coaxial aerial cable such as KBL 7. Polarity of the supplied
aerial is not important, although if using coaxial cable then connect the screen (ground) to the right hand
terminal closest to the PCB screw.
Double check all connections and, if all is well then fasten the panel into the mounting box. Switch on the
power source and observe the LED's. If all is well the blue "Bluetooth" LED should be flashing slowly. Press
the “power” button on the front panel once (or press power on the remote control) and the blue LED sho uld
change to red to indicate the unit is in standby. Power on again and cycle through the inputs. If there are no
unexpected sounds then it's probably all connected correctly and it should be safe to proceed to the operation
instructions. Do not fasten down the tabs until you are certain that everything is working as it should!
Installation continued..
DC input
12-18v
3500mA
Reserved for
programming
Line input
terminals
(as viewed)
+ Right
- Right
- Left
+ Left
FM aerial
connection
75 ohm
Right
speaker
connection
Left speaker
connection
Connections for Power, Line Input and Loudspeaker Outputs are located on the rear PCB.
Pre-amp line
output for use
with slave
amplifier
Note that the loudspeaker and line input screw terminal blocks can be pulled upwards and detached
from the PCB to make connection and installation easier.
Volume
There are 256 steps to the volume control from a minimum volume of 0 to a maximum volume setting of
255. These are accessed by pressing the volume up and volume down buttons. The 10 number keys from
zero (minimum) to 9 (maximum) provide quick way of selecting a range of preset volumes within this range.
Please note that the volume control system used does not go to absolute zero volume, the mute button is
provided for when you require the unit to produce no sound.
Operation. Front panel overview
Stores the current radio
station to the current
location.
Switches between
Bluetooth, radio, PCB
line input and jack
Mutes the output.
Switches between
standby and on.
Seeks up to the next
radio signal.
Switches between
stored radio stations.
Volume up.
Volume down.
3.5mm jack socket input
Receiver window for
the supplied IR
remote control.
Status indicator
LED's
Bluetooth mode
In Bluetooth mode a slow flashing blue LED indicates that no Bluetooth device is connected. F5 will turn
pairing on and the blue LED will flash more quickly. F6 will turn pairing off (and the blue light will flash slow
again). If a Bluetooth device is currently connected pressing F5 will also disconnect from that device.
Pressing F4 will turn Bluetooth auto connect (to previously paired devices) on and off. The Bluetooth LED
will flash red once for auto pairing on and twice for auto pairing off. If your device request a pairing code
please enter 1234
When a device is connected: F1 sends a play/pause command to the device. F2 sends stop command to
the device. The large up and down buttons (above/below mute) send next and previous track command to
device.
The default Bluetooth ID is KeeneBlue. If you have more than on Bluetooth amplifier you may wish to
change the ID to make each amplifier unique. This is achieved by performing a factory reset as detailed
later in this document.
Notes
When the unit receives power it will
revert to the last used input. In the
event of a power failure the amp will
come back on in to standby mode and
will remember the last stored
parameters.
It is safe to leave the amp in standby
as very little current (less than
100mA) is used in that mode. In
standby only the Red power LED will
be illuminated. This is the normal
method of switching off.
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