Ramsey Electronics UAM4 Manual page 23

DETAILED JUMPER SETUP INFORMATION
In the following explanations and tables, an 'X' in two adjacent columns
indicates a jumper is installed between those two adjacent pins of the header.
The factory default/recommended modes for the options are indicated by '**'
placed before the option setting.
Input Mode selection
Stereo and monophonic input modes are selected with the 'INPUT MODE'
jumper 'H3' located near the input connectors 'J1' and 'J2'. For stereo
operation no jumper is installed on H3. Mono operation is enabled by
installing a jumper on H3.
For stereo mode the jumpers between the L (left) and R (right) jumper
locations near the output terminals MUST NOT be installed. For mono mode
you may use the left and right outputs as separate channels at 20 watts each
by not connecting the 'L' and 'R' jumpers. By installing the 'L' and 'R' jumpers
as indicated you will have a single output at 40 watts. These jumpers MUST
be installed in the provided locations on the circuit board. DO NOT simply
connect the outputs together at the output terminals as damage to the AX9708
may result. In mono mode the input is applied to the right channel input. Any
signal on the left input is ignored.
Mode
Mono 1x40W
Mono 2x20W
**STEREO
Audio Gain Selection
Jumpers 'H4' and 'H5' set the UAM4 gain. The input signal level will
determine how these are configured. If you are wondering just what 'dB' is, it
stands for 'decibels' and it is a unit of measure for sound intensity or level. To
give a very simple explanation, every 3dB of voltage gain represents an output
voltage increase of 1.4 times the input voltage. Therefore with a gain of +3dB
an input voltage of .1 volt will produce an output of .1 x 1.4 = .14 volts. A gain
of +22dB will produce an output voltage of (22 / 3) x .1 x 1.4 = 1.03 volts with
the same .1 volt input. For power calculations a gain of 3dB is simply a gain
of 2. So for a gain of +22dB with a 1 watt input the power output will be (22/3)
x 2 x 1 = 14.67watts. If you want to learn more about decibels we suggest
you search the internet for the key word 'decibels'. There are many good
resources available that will give more in depth information.
INPUT MODE JUMPER CONFIGURATION
H3
1 2
X X
X X
L+ to R+ L- to R-
X
UAM4• 23
Input
J1
X
X
J2
X
X
X