User Manual

MCM-20.4 Iss1
Preliminary User Guide v1.1
2
DESCRIPTION
The MCM-20.4 is a 20 x 4 channel summing mixer.
It employs a unique configuration, offering 20 input channels arranged as follows: 16
are implemented in 2 rows of 8 channels each, being the remaining 4 assigned to the
master section, hard panned left and right in pairs. Unlike classic consoles employing a
complicated switching matrix for subgroup assignment, the channels have a fixed-
assignment in groups of eight. This arrangement not only makes the unit fit in a four-
unit rack space, but greatly helps in making it affordable. Each channel features center
detent Pan and Fader concentric controls plus balanced insert and mute switches.
The insert send points always have the signal present, so they can be alternatively used
as direct outputs for recording without additional patch bays.
The 16 channels implemented on the front panel feature aux sends. A total of 4 different
sends can be assigned, with a maximum of 2 per channel simultaneously. AUX 1 and 2
or 3ST can be assigned on a per channel basis, but not all 4 sends can be used on the
same channel at the same time.
Each group has its own stereo fader and balanced insert point and all 4 stereo subgroups
are passively summed into the master bus. The gain is restored by means of a 1073 style
class A, transformer coupled, mic preamplifier, featuring a total of 4 transformers (2 in
each channel).
The master section is also provided with its own balanced insert point.
All connections on the back are made by DSUB 25 connectors following the Tascam
*
protocol, with the exception of the master bus connections, which are by dedicated
XLRs.
Comprising vintage quality sound with sophisticated routing options, the MCM20.4 is
the perfect partner for hybrid setups, integrating analog gear with your DAW.
Lots have been written on the pros and cons between active (current) and passive
(voltage) summing topologies. Some may claim one is better that the other but truth is
active summing is less susceptible to noise and voltage, passive summing has a nice,
vintage sound associated with its gain makeup circuit.
The smart hybrid summing topology used in the MCM20.4, where the channels are
current-summed ( active ) into their corresponding subgroups and the subgroups voltage
summed ( passive ) into the master section, has proven to give massive headroom and
lower noise without making any compromises to its vintage characteristic sound.