AMERITRON AL-811H Owner's Manual - Page 15

Browse online or download pdf Owner's Manual for Amplifier AMERITRON AL-811H. AMERITRON AL-811H 19 pages. Hf power linear amplifier
Also for AMERITRON AL-811H: Instruction Manual (12 pages), Unpacking Instructions Manual (11 pages), Manual (13 pages)

Print Page
AMERITRON AL-811H Owner's Manual
(Fig. 22)
The Zener diodes in the kit connect in series with the transformer white center tap lead. The
banded or striped end connects toward the transformer, Fig. 27, since they are Zener diodes.
Each diode is rated at 5 watts and adds 3.3 volts of bias. They are safe to 1.5 amperes
continuous when in open air.
I suggest you use one Zener diode in addition to the 6 rectifiers used by Ameritron for a total of
about 7.3 volts, or two Zener diodes in series if your amplifier does not have any bias rectifiers.
There will not be any noticeable increase in IMD from the additional bias, and the tubes will run
a lot cooler. Please look at this dissipation graph. Anything over 65W is over the tube rating.