User Manual

MCM-20.4 Iss1
Preliminary User Guide v1.1
14
GAIN STRUCTURE
The gain structure in the MCM20.4 is quite simple and intuitive. At the same time, no
compromises have been made on the “secondary” inputs and outputs, like the inserts sends
and returns and aux sends. Therefore all connections are balanced and all outputs are nominal
+4dBu and able to drive 600 ohms.
The gain structure is that all faders up, any input to any output is unity gain.
+4dBu at one channel input, fader all the way up, subgroup fader all the way up, gives +4dBu
at the channel and subgroup insert send points, and at the main send and output as well.
+4dBu at the channel or subgroup insert returns will give +4dBu at the main send and output
as well.
+4dBu at the main insert return will give +4dBu at the main output.
+4dBu on a channel input, sends pre fader, will give +4dBu at the corresponding aux output.
MCM 20.4 POWER SUPPLY
The MCM range of summing mixers features a hybrid power supply concept, in a very similar
way to the On Slot Technology (OST) employed in Heritage´s successful 500 series enclosures
range.
An external switching power supply enters the unit by means of a 5 pin XLR connector, where
it is further filtered using a PI configuration, using a big common mode choke.
Further, linear regulation stages are used. Different regulation is used for channels and buses,
and output stages.
TECHNICAL SPECIFICATIONS
- Channel Input Impedance: Greater than 20 Kohm.
- Maximum channel input level: Greater than +26dBu
- Maximum insert return input level: Greater than +26dBu
- Maximum insert send level: Greater than +27dBu, able to drive 600 ohm.
- Maximum aux send output level: Greater than +27dBu.
- Maximum main output level: Greater than +26dBu into 600ohm.
- Frequency response: ±0.5dB 20Hz to 20kHz
- THD + N: Not more than 0.07% from 50 Hz to 10 kHz at +20dBu output (22 Hz to 22
Khz bandwidth) into 600Ω.
- Noise, all faders up, all subgroups in, measured at the main output, 22Hz to 22Khz:
Better than -80dBu