4.3. Channel gain and equalization
These controls allow individual input sensitivity and tone adjustments for each
channel.
Thanks to the GAIN (2) control, you can precisely adjust the signal level of an
incoming musical signal to match the level of the music that is playing on air through another
channel. This operation may be performed visually (through the VU-meters) and acoustically
(through the headphones), successively comparing both signals with the PFL buttons. The Gain
knobs offer an adjustment range of ±20dB.
The tone controls (3-4-6) of channels 1 and 2 have a range of -20 to +10dB, while
channels 3 and 4 range from CUT to +10dB.
4.4. Using the CROSSFADER
The MAC40v provides a short travel sliding potentiometer placed horizontally. This
potentiometer is called CROSSFADER (24) and enables a direct mixing of the signals present at
the inputs. The odd channels 1 and 3 feature a XFA switch with activation indicator, that
assigns this channel to side A of the crossfader. If these switches are not activated, the signal
bypasses the crossfader circuit and passes directly to the main mix bus. An analogue XFB
switch at the even channels 2 and 4 assign these signals to side B of the crossfader or direct
them to the main mix bus.
The MAC40v's CROSSFADER is based around an electronic VCA circuit that greatly
extends its life and additionally has the great advantage of being removable and replaceable by
yourself. To do so, just follow these instructions:
1- Remove the screws of the plate that hold the CROSSFADER.
2- Remove the set from the mixer.
3- Detach the multipin connector.
4- Replace the whole set or remove the screws that tie the potentiometer.
5- Tie the new potentiometer and the associated printed circuit and multipin
connector to the plate.
6- Attach the multipin connector.
7- Place the set on the mixer.
8- Fix the screws of the plate.
4.5. Outputs
The MAC40v mixer has two independent outputs, OUT1 and OUT2. Each one has its
own volume control, with a sliding fader for OUT1 (21), and a rotary one for the OUT2 (12).
Both outputs have a common balance control BAL (20) and a MONO (19) switch that converts
an stereo signal into a monophonic one or sends one side to both channels.
You must be careful when setting up the general output level of the mixer. The "clip"
display of the connected power amplifiers must never remain permanently lit, but do it only
occasionally by following the rhythm of the bass signals that are being played.
The MAC40v mixing unit is factory adjusted at 0dBV/1V, although this output can be
internally modified to +6dBV/2V. See diagram 7.1.
7