Bugera 1960 - Inside the BUGERA 1960; Internal Components and High Voltage Warning; Bias Adjustment and Testing; Wiring the BUGERA

7 BUGERA 1960 User Manual
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Inside the BUGERA 1960
(20)
(21)(22)(23)
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.
(20) These are the sockets for the ECC38A/B/C preamp valves.
(21) These are the sockets for the EL34 power amp valves.

(22) The BIAS TEST connector lets you connect a voltmeter in order to measure
the power amp valves (bias adjustment). Make sure that the voltmeter is set
to direct current (DC).
(23) The BIAS ADJUST control is used to make the bias-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 temperatures 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
AMPLIFIER WITHOUT A LOUDSPEAKER CONNECTED!
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 cabinets 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 diering impedance values, the speaker
with the lower impedance will provide the highest output power. In this case the
IMPEDANCE switch must be set to half the value of the speaker with the lower
impedance value. Example: 16 ohms + 8 ohms -> 4 ohms.