13
Select Alternate Jumpers
Figure 5: Output Jumpers
Level programming should be done at the time of installation. Remove the unit’s top cover and
locate the six pairs of 2 x 4 headers along the front of the main (lower) printed circuit board. Each
input has headers for left and right channels. The header pairs are numbered 1 to 6.
Jumpers on the headers are used to set channel input sensitivity. A position guide is printed on the
circuit board near input two. Move the push-on jumpers for left and right channels to the desired
position. For example, for a +4 dBu input set the jumpers to the second position from the left. See
figure 4.
When input jumpers are set correctly, all inputs will produce the same internal level on the LX-1’s
mixing busses. This internal level will p4 dBu or +8dBu at the output, depending on the
setting of the output level jumpers.
The LX-1 12-segment program level bar displays may be used as a convenient aid for trimming
the source levels. This is especially handy when a level meter is not available, or would be
inconvenient to use.
Normal program output level, or “0,” is indicated by the left and right channel yellow LEDs. “0”
on the display indicates 4 or +8 dBu output. The point where the LED comes on is a very
accurate indication of “0” level. There is a very narrow “flutter” range as the LED comes on.
This, plus the visibility of the distinctive yellow LED, permits accurate level setting even from
across the room.
The next step is selecting the nominal program output level of the LX-1 This can be 4 or
+8 dBu. The output level jumpers are located to the left of the main buss jumpers near cable
connector J 1. For +4 dBu output the jumpers should be on the two outer pins. For +8 dBu the
jumpers should be on the two inner pins. See figure 5.
While the cover is removed from the LX-1, you should decide how the SELECT mode will
function. In the normal SELECT mode (while MIX is not on) selecting a new source will switch
to that source and cancel the previously selected choice. Selecting the same source again will not
do anything. When the 51 juniper on the logic board is moved from SEL to ALT, the LX-1 will
respond to channel selection by alternately turning the selected channel on and off See figure 6.