Mono Mic/Line Channels; Input Level Setting; Mono Channel Insert; Low Cut Switch - Alto AMX-140 User Manual

4.1 MONO MIC/LINE Channels

These are channel 1 through channel 4. You can connect balanced, low impe-
dance microphones to the XLR socket. On the 1/4" phone jack you can connect
either a microphone or a line level instrument. You shall never connect an un-
balanced microphone to the XLR socket if you do not want to damage both the
microphone and the mixer.
48 Volt phantom power
It is available only to the XLR Mic sockets. Never plug in a microphone when
phantom power is already on. Before turning phantom power on, make sure
that all faders are all the way down. In this way you will protect your stage
monitors and main loudspeakers.

4.2 INPUT LEVEL Setting

This control is provided with 2 different indication rings: One is
for the microphone and the other for the line levels. When you
use a microphone you shall read the OUTSIDE ring (0~44 dB),
when you use a line level instrument you shall read the INSIDE
ring (+15~-30 dB). For optimum operation you shall set this control
in a way that the peak LED will blink also occasionally in order to
avoid distortion on the input channel.

4.3 MONO Channel INSERT

Insert points are provided for each mono MIC channel, which can
allow you patch external signal processing devices into signal
path. When you insert a TRS jack in the insert socket, the signal
will be taken out after the input gain control (Trim), sent to an ex-
ternal processor such as a compressor-limiter, and returned into
the channel strip immediately before the EQ section. Of course,
the jacks used must be stereo (Tip Send/Ring Return).

4.4 LOW CUT Switch

By pressing this button you will activate a 75 Hz low frequency filter with a slope of 18 dB per octave. You can use
this facility to reduce the hum noise infected by the mains power supply, or the stage rumble while using a microphone.
1
2
3
4
5
9
MIC 1
J.T. J.T.
2 1
3
BAL OR BAL OR
UNBAL UNBAL
LINE IN 1
INSERT
TRIM
+15dB +15dB -30dB LINE -30dB LINE
0dB 0dB 44dB MIC 44dB MIC
LOW CUT LOW CUT
75Hz 75Hz
18dB/Oct 18dB/Oct
ON
OFF
PHANTOM
POWER
2
1
4
3
5