Powering of the microphone
The required PSU is included with the microphone. It is clearly
marked and should be quite obvious by connector type and size
how to connect the microphone to the power unit with the supplied
CM49 microphone cable. The audio signal may be taken from the
transformer-balanced power unit by a conventional audio cable with
standard XLR-type connector.
After connection of the microphone, the power supply, and AC line,
the main switch may be switched on. Operating condition will be
indicated by the power lamp.
The warm-up time of the CM49 is approximately one minute. When
your CM49 is new, a 24-hour burn-in period is recommended.
The CM49’s tube will “break in” over a period of time enabling the
mic to sound subtly better over a period of time.
2. The CM49 Power Supply
This PSU supplies the microphone with the 4.0V filament voltage
and 120V plate voltage for the vacuum tube.
Prior to connecting the CM49 to AC power, check the AC voltage of
the power line you are going to connect to the CM49.
The CM49 PSU has an internal AC voltage selector switch.
To check the CM49 PSU AC voltage selector switch, first unplug the
AC cable (power plug) from the PSU.
Use a flat-blade screwdriver to unscrew the lid to the PSU and
remove the lid.
You will see a small chrome toggle switch located inside the unit
directly next to the large AC transformer.
To set the switch to 115V, toggle the switch towards the
transformer. To set the switch to 230V, toggle the switch away from
