Master & Power Indication Valve
The MASTER control sets the overall signal level sent to the power amplifier stage and,
depending on the setting of the FULL/HALF POWER switch on the rear panel, the stage
volume. This is visually shown by the EM84 Power Indication Valve (valve furthest right).
As the MASTER control is increased and/or the instrument is played harder, the top and
bottom bands on the indication valve will increase in size, pulsing as each note is
played. The level at which the two bands touch is when the power stage has reached its
maximum rated clean output power. Beyond this the valve power stage itself will start to
saturate adding its own warmth and tone to the overall sound.
N.B. The Power Indication Valve circuitry has been calibrated so that in the FULL
POWER setting the two bands will touch when the amplifier produces approximately
400 watts RMS with the rated nominal mains voltage applied.
Standby/On toggle switch & front panel lamp
As the name implies, this switches the amplifier from STANDBY mode, where only the
valve heaters and low voltage DC circuits are on, to ON for actual use. This should be
used correctly every time the unit is used to prevent problems with valves and increase
their life.
The large green lamp on the front panel is independent of the STANDBY switch and
should be lit when the green ON/OFF switch on the rear is set to ON.
Before the green power switch is switched to ON (rear panel), make sure the front
panel toggle switch is in the STANDBY position. After switching the power on, wait at
least one minute before switching from STANDBY to ON. This will ensure that the valves
have time to warm up before large voltages are applied to them. During short breaks the
amplifier can be switched to standby and will therefore be ready to play when next
needed.
6
To Next Page
Loading...
