Balanced Audio REX II Power - Manual (Page 8)

Operating the REX II Power
Normal operation of the REX II Power amplifier requires simply turning the
unit on. There are no meters to connect, bias setpoints to remember, or
drifting bias points to adjust. Please read the Autobias Feature section
for more details.
Turning the REX II Power ON:
The main power switch is located at the rear of the unit. When you turn
the unit on, it will go through a gentle power-on sequence. After about
one minute, four LED’s visible from the top of the chassis should light up.
This indicates that full operating bias has been reached and the unit is
now ready to play.
Turning the REX II Power OFF:
The unit can be turned Off at any time (even while playing). If needed,
please wait at least 30 seconds before turning the unit ON again.
Autobias Feature:
The REX II Power implements a sophisticated autobias circuit that
automatically compensates for tube aging and line voltage fluctuations,
as well as marginal mismatching of tubes. The successful operation of
the autobias circuit is noted by individual LED’s that glow visibly next to
each output tube when viewed from the top of the chassis. A total of
four LED’s should light up to indicate proper operation of the circuit. If
one of the LED’s fails to light up (after the unit is warm), there could be
two reasons for this problem:
1. The particular output tube is defective. In this case replacing
this tube with a known good one should turn the LED ON again.
2. The amplifier was overstressed and its thermal protection was
activated. Simply turning it OFF and then ON again will clear that
protection.
NOTE: For more details on the operation of the REX II Power protection
circuit please see the correcponding chapter.