7
Biasing TDS power tubes and other technical info
Biasing and Internal Adjustments:
Part of chassis and circuit board is shown below with the chassis sitting on its transformers, and front
panel facing you. There are exposed high-voltages in this chassis, even with the amplifier shut-off! If you
are not familiar with tube
amplifiers and/or high voltages, do not attempt to remove the chassis from its cabinet or to attempt to
service this amplifier. Refer servicing to the factory or to someone with experience servicing these types
of amplifiers.
High Internal voltages inside this amplifier can cause harm or Death!
AC Balance:
This is factory set for linear clipping at maximum power output, and is set with an
oscilloscope for proper adjustment.
Bias Controls:
Each tube is factory set for .030 Volts (30 millivolts) measured on the one-ohm cathode
resistors connected to each power tube pin 8. This should be set with the amp cold,
then reset after the amp has run for about an hour. Use a reliable digital volt
meter for these settings.
Hum Balance AC Balance Power Tube Bias
DISCLAIMER:
There are exposed Internal high-voltages in this amplifier. Do not attempt to service, repair
or conduct tube biasing unless you are qualified to do so. Please contact Fuchs Audio beforehand with
questions in this regard. Fuchs Audio takes no responsibility or shall be held liable for any personal harm
caused or damage to this amplifier as a result of unauthorized service, repair or internal adjustments
made to this amplifier
.
