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PPM608
PPM608
Channel Controls
The eight vertical channel strips look very similar,
with only a few differences between them. Each
channel works independently, and just controls the
signals plugged into the inputs directly below it.
Mono Channels 1 to 6
• Channels 1 to 6 are mono channels, and their
controls affect either the mono mic input or the
mono line-level input.
• Channels 1 to 4 have a built-in signal in-line
compressor circuit with adjustable threshold.
• Channels 5 and 6 have a hi-z switch [30] so you
can connect guitars directly.
• The 3-band EQ has shelving high, shelving low,
and peaking mid EQ.
• The mono signals are split equally to the left
and right of the main mix.
Stereo Channels 7 to 8
• Channels 7 and 8 are stereo channels, and their
controls affect either the mono mic input,
stereo line-level input, or stereo RCA inputs.
(The mono mic input of each stereo channel is
split equally to left and right).
• The stereo channel EQ is a 3-band design just
like the mono channel EQ.
“U” like Unity gain
Mackie mixers have a “U” symbol on almost every level
control. It stands for “unity gain,” meaning no change in
signal level. The labels on the controls are measured in
decibels (dB), so you’ll know what you’re doing
level-wise if you choose to change a control setting.
Signal Flow
The block diagram on page 29 shows the signal flow,
but here is a short description of the flow through the
channel strip section:
The mic inputs and mono line inputs each feed a
preamplifier whose gain is set by the gain switch [28].
The stereo channel line inputs and RCA inputs do not go
through a gain-selectable preamp.
The signal then passes through the compressor circuit
(ch. 1 to 4 only), then through the channel EQ, and the
channel level [27].
The mon 1 control [21] taps the signal off just before
(pre) the channel level.
The FX/mon 2 control [22] taps the signal off before
(pre) and after (post) the channel level. The FX send/
mon 2 send switch [47] lets you choose which is used.
Post is used for FX, and pre is for monitor 2.
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