UM30, UM60, UM90 User Manual
Connection and setup
Connect the rear IEC inlet (12) to the mains using the supplied mains lead (or an equivalent approved type).
Alternatively, the UM series amplifiers can be powered by a 24Vdc power supply, such as a truck or boat
battery, by connecting t
he “+” and “
-
” of
the battery to the 24Vdc INPUT (15) on the rear panel. Ensure that
DC cables are capable of handling the current (4A or higher recommended)
(Note: For UM90 operating from 24Vdc power, the output is reduced to 80Wrms)
Connect a microphone (if required) to the front panel jack input (9).
Connect any line level audio inputs to the LINE IN connectors (17) on the rear panel using good quality RCA
leads. An additional 3.5mm AUX line input (1) is provided on the front panel for connecting a playback device
such as a smart phone or MP3 player.
Further amplifiers can be connected from the rear LINE OUT sockets (16)
For stable F
M radio reception, connect the Antenna ‘F’ type socket (
18) to a suitable FM antenna.
The UM series amplifiers can be used either as 100V line amplifiers or standard low impedance power
amplifiers. These 2 configurations cannot be used together, so it is important to decide which method will be
used at the start.
100V line systems
For 100V line systems, connect the amplifier to the first speaker in the system using double-insulated speaker
wire which has adequate current rating to handle the total output of the amplifier.
Connect
the “100V”
output terminal to the positive (+)
connection of the speaker and “COM”
output to the
negative (-) connection of the speaker (14). Connect further speakers in parallel to the first speaker with all
positive terminals connected together and all negative terminals connected together as shown below.
A 100V line speaker system can comprise of many speakers connected together. The determining factor for
how many speakers can be used on a single amplifier is the power rating. For most purposes, it is advised to
connect as many speakers as need
ed with a combined wattage of no more than 90% of the amplifier’s output
power rating.
The terminals of a 100V speaker are connected to a transformer and in some cases, this transformer may be
“tapped” for different power ratings. These tappings can be u
sed to adjust the wattage (and output volume)
of each speaker in the system to help achieve the ideal total power of the system for the amplifier.
Low impedance systems
The UM30/60 amplifiers can alternatively provide an output for a single 8
Ω speaker by
connecting the “
8
Ω”
output
to the positive (+) speaker connection and “COM” output
to the negative (-) speaker connection. It is
important to ensure that the speaker load is no lower than 8
Ω and that the power handling of the speaker
is
equal to or greater than the output power of the amplifier.
