7. If using the front panel POWER button, when the amplifier is in standby mode, (as indicated by the steady
blue ---- on the display window) turn on the amplifier by pressing and releasing the red POWER button
once. The blue POWER light starts blinking as the amplifier goes through its countdown and power up
sequence. The amplifier can be powered off at any time by touching the POWER button once again, where
the blue POWER light turns off, and the amplifier goes back to the standby mode with the Display Window
showing the steady ---- standby mode signal.
RS-232 commands: >POWER ON for powering on the amplifier, and >POWER OFF for powering off
the amplifier
The power on warm up sequence takes approximately 240 seconds, with the countdown status displayed on
the numeric
Display Window
(if not suppressed). This process uses an advanced microprocessor controlled
timing technique to enhance tube life by warming the tubes up slowly and applying the high tension with a
gentle ramp up, only after the tubes are properly warm and ready to conduct. The autobias system biases the
tubes into cutoff and the fault sensing system monitors continuously for faults.
During this warm-up period the amplifier is in the muted mode, and will stay in the muted state until all the
output tubes are biased properly. If powering on for the first time after clearing the stored bias values, the
bias process can take longer than the indicated 240 seconds, in which case the counter will stop at 000 and
the MUTE light flashes while the bias process is being completed. This process can take up to 60 seconds
after 000.
8. After the power on warm-up sequence is completed, the amplifier automatically goes into the operate state.
The POWER light turns into a steady blue light and the MUTE light turns off, indicating that the amplifier is
ready to receive audio signal.
S-400 Amplifier Owner’s Manual
VTL
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