Classe Audio CAV-500, Service Manual

Page: 9 / 28

PRO-SVR_LEGACY Page 9 of 13
Calibrations and Adjustments
Bias adjustment:
Note: Bias adjustment should be made without any load connected to the amplifier’s output, and no signal
connected to the amplifier’s input.
1. Connect a multimeter to R112 leads and set the multimeter to mV scale.
2. Turn trimpot R104 counterclockwise until it reaches 0
ƻ . A click should be heard.
3. Turn on amplifier, and let it warm up for 15 minutes on idle.
4. Adjust trimpot R104 to get a 5mV reading.
5. Let the amplifier warm up for a 24 hours period with signal and load.
6. Remove signal and load, and reconnect the multimeter, setted to mV scale, to R112 leads. Note the
reading, and readjust if necessary.
DC offset:
Note: DC offset adjustment should be made without any load connected to the amplifier’s output, and no
signal connected to the amplifier’s input.
On these units, DC offset can’t be adjusted. Measure DC offset using a voltmeter connected to the output
posts, scale setted to mV. DC offset should be less than 10mV.