Alto Dragonfly PM-12 Service Manual page 67

6dBu (+/-2dBu) THD+N<0.10%, and the outputs of SUBGROUP OUTPUT 1-2 and 3-4 are -
6dBu (+/-2dBu) THD+N<0.10%. adjust the faders of SUB1-4 of Sub1-4 of SUBGROUPS you
can control the output level of respective SUBGROUP OUTPUT1-4. While connected an
unbalanced plug at SUBGROUP INSERT, there will be no output on SUBGROUP OUTPUT1-4.
D. Press the left and right keys of SUBGROUPS ADDIGN TO MAIN MIX, the SUB signal will be
added on MAIN MIX OUTPUT.
E. Connect unbalanced 4Db INPUT TO line in 9 and 11 independently, measure the balanced
output of MAIN MIX OUTPUT and it shall be 0dBu (+/-2dBu) THD+N<0.10%. Connect
unbalanced 4db input to LINE IN 10 and 12 independently, measure the balanced right output
of MAIN MIX OUTPUT and it shall be 0dBu (+/-2dBu) THD+N<0.10%, while there is no output
on left output of MAIN MIX OUTPUT.
(18) Connect the RCA plug (unbalanced input 0db) to the left and right inputs of TAPE IN:
Press the 2TK TO MIX down, measure unbalanced output of MAIN MIX OUTPUT
(LEFT&RIGHT), as well as TAPE OUT, the measurements will be 0dBu (+/-2dBu)
THD+N<0.006%
Release the 2TK TO MIX (OFF), there will be no output on CONTROL ROOM.
When press 2TK TO CONTROL ROOM down, the CONTROL ROOM output shall
be 0dBu (+/-2dBu) THD+N<0.002%
(19) Input a +15dBu 1KHz sine wave to the LINE1 (load out 600Ω BNC-Unbalanced), turn
MAIN MIX LEVEL to smallest in counterclockwise, then all LED LEVEL indicators will be off. Then
slowly turn MAIN MIX LEVEL in clockwise, the LED LEVEL indicators will be lit in sequence. Now
measure the MAIN MIX OUTPUT (LEFT & RIGHT) and it will be same as the LED indicators: i. e.
that which indicator is lit and its value will be same as the output. Also, the maximum distortion-free
value shall be 20dBu (+/-1dBu, THD+N<0.1%)
(20) Turn the TRIM knob of CHANNEL1, the peak LED will be lit in red. It will be same on CHANNEL
2~CHANNEL12.
5. Effects test:
(1) Press MAIN MIX button of AUX RETURN SOLO, now the digital effects are added on the MAIN OUT
signal, and the output signal is constantly changing via a oscilloscope. Now turning PRESETS or
ARATIONS knobs and the type and level of effects signal can be changed. Press DSP MUTE, the
digital signal will be disabled but there is output on MAIN OUT, the curve is stable and PEAK LED is
lighting, which indicates the digital effects is OFF.
(2) Connect a footswitch into the FOOTSWITCH jack, press FOOTSWITCH it will be same as above.
6. Frequency response test:
Test of MAIN MIX OUTPTU (LEFT & RIGHT) while using input of independently according to following
procedures. ( All controls setting is same as 4.2)
(1) LOW CUT test: turn on the test program, input a +15dBu 1KHz Sine wave (Load out 600Ω BNC-Unbal)
to LINE1, LINE2, LINE3, LINE4, LINE5, LINE6, LINE7 and LINE, the frequency response curves are
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