Ampeg HERITAGE SVT-CL - Manual (Page 10)

Heritage SVT-CL Bass Guitar Amplifier
10
Block Diagram
The Bias 1 control adjusts the three left (front left, rear left and rear center) power tubes. The Bias 2
control adjusts the three right (front right, rear right, and front center) power tubes. By observing the
LEDs as the Bias controls are slowly rotated clockwise, a number of tube problems may be diagnosed by
the user as seen in the table below.
Condition
Problem Solution
Green comes on, then red No problem The longer the green LED is on before the red LED
comes on, the better matched the tubes are.
Red comes on, then green Tubes not properly matched Set slightly before green comes on, obtain matched
tubes when possible.
Red comes on, no green One or more tubes are non-functioning Check to make sure tubes are all seated properly; if so,
find and replace bad tube(s).
None on Possibly no high voltage or bad Bias Have unit checked by a service technician.
Control or bad tube(s)
Both on all the time Possible bad Bias Control or bad tubes Have unit checked by a service technician.
If the tubes are bad enough to cause damage to the unit, the Fault Indicator (#11, Front Panel) will signal
and the unit will shut down.
BIAS
ADJUST
SPEAKER
OUTS
0dB INPUT
GAIN
ULTRA
LO
MID
FREQUENCY
MASTER
BUFFER
PREAMP
OUT
PWR AMP
INPUT
SLAVE
OUT
BAL
OUT
1/4" JACK
1/4" JACK
POWER
AMP
POWER
STANDBY
FAULT
BIAS
INDICATORS
ULTRA
HI
-15dB INPUT
BASS TREBLE
4 OHMS
2 OHMS
IMPEDANCE
POWER AMP
PROTECTION
SPEAKON ®
JACK
1+
2+
1- 2-