User manual

en
Wiring the BUGERA
7
Inside the BUGERA
DANGER!
*
High voltage! Risk of death!
High voltages of up to 500 V DC may be
present inside the casing for long periods
after being disconnected from the mains.
To avoid lethal electric shock, do not open
the casing. There are no user-serviceable
components inside. Refer all maintenance
to qualied service personnel. Remove the
mains cable when the unit is not in use.
The parts inside the amplier operate at
*
high voltages and high temperatures. To
avoid damage and injury that results from
re or electric shock, do not drop or spill
anything into the unit’s casing.
INSTRUCTIONS FOR QUALIFIED
SERVICE PERSONNEL ONLY
Remove the backside of the amplier’s casing to get to
the valves and the control elements.
These are the sockets for the 29 ECC83/ECC83A pre-
amp valves.
These are the sockets for the 30 5881 power amp
valves.
*
The 31 BIAS TEST connector lets you connect a volt-
meter in order to measure the power amp valves
(bias adjustment). Make sure that the voltmeter is
set to direct current (DC).
The 32 BIAS ADJUST control is used to make the bi-
as-adjustment.
Replacing the power amp valves also requires
$
bias adjustment. You should always use sets
of four matched valves. The valves of the
BUGERA Series are ideal for this purpose.
CAUTION: WE HIGHLY RECOMMEND THAT
!
BIAS ADJUSTMENTS BE CARRIED OUT BY
QUALIFIED PERSONNEL!
Wiring the BUGERA
CAUTION!
!
Hot! Risk of injury! During use, the valves
will get very hot and high surface temper-
atures may be reached at the rear of this
unit. To avoid burning yourself, make all
connections while the unit is still cold.
ATTENTION! TO AVOID DAMAGE TO YOUR
!
AMP, NEVER USE THE BUGERA VALVE AM-
PLIFIER WITHOUT A LOUDSPEAKER CON-
NECTED!
The BUGERA amplier has two paralleled LOUDSPEAKER
outputs which are used to connect one or two speaker
cabinets.
If you only connect one speaker cabinet, be sure that the
IMPEDANCE switch is set to match the impedance of the
connected cabinet.
If you want to connect two speaker cabinets, both cabi-
nets should have to the same impedance. Be sure to
have set the IMPEDANCE switch correctly. In this case,
set it to half the value of one of the cabinets. When using
two 16-Ohm cabinets, the switch therefore needs to be
set to 8 Ohms; and with two 8-Ohm cabinets, set it to
the minimum impedance of 4 Ohms.
When you use two speaker boxes with differing imped-
ance values, the speaker with the lower impedance will
provide the highest output power. In this case the IM-
PEDANCE switch must be set to half the value of the
speaker with the lower impedance value. Example: 16
ohms + 8 ohms -> 4 ohms.
Impedances
Connecting a speaker