Ramsey Electronics UAM4 Manual page 22

each input.
These inputs are high impedance which means they can be bridged or
connected in parallel with other equipment inputs.
Left And Right Outputs (J6, J7, J8, J9)
These are the output connections to the speakers. They are labeled 'L+', 'L-',
'R+' and 'R-'. The polarity is important when connecting the speakers in order
to assure the speakers are 'phased' correctly with respect to each other. If
they are connected opposite each other, any sound centered between the two
channels will 'appear' to be coming from each speaker rather than from a
location between them. It also indicates the 'phase' with respect to the input.
Either terminal of the output may be connected to either terminal of the
speaker but each speaker should be connected in the same way. See the
'Neat-To-Know Information' section at the end of this manual to learn how to
determine the 'phase' of a speaker if it isn't labeled.
Power Input (J5)
This is the power supply input connector. You may use any power supply with
an output voltage of 10VDC to 18VDC and a current rating of at least 2.6
amps. It is possible to use a supply with a current rating of less than 2.6
amps, but you won't get the full 40 watts of output at 18 volts. When the
UAM4 was being developed, we used a supply with less than 1 amp capacity
and it still gave us plenty of power for initial testing purposes (plus helped
protect the circuit against mishaps, (which never happen during design
stages! ), and let us see what was going on without the possibility of producing
flames on the bench.
It is important that you observe the polarity of the connections. The positive
lead of the supply MUST be connected to the center pin terminal and the
negative MUST be connected to the outside shell of the jack. Failure to follow
this will most likely result in damage to the amplifier.
Mute And Shutdown Connectors (J3, J4)
These connectors provide access to the 'MUTE' and 'SHUTDOWN' functions
of the MAX9708. The lines are a digital type input and have a high level of 7.5
VDC applied to them when not active. By connecting these lines to ground
the function is activated. Activation can be accomplished by simply
connecting the two terminals on the desired function connector together with
an external switch or even an external logic signal to ground. Note that if a
jumper is installed on the 'Auto Shutdown' on jumper 'H9' the 'OVER TEMP'
LED will light when the selected function is activated from the 'MUTE' or
'SHUTDOWN' connector. If no jumper is installed on 'H9' then activation of
either function will not activate the LED.
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