[AMPS] SB-220 Idling Current

Rod Fitz-Randolph w5hvv@aeneas.net
Sat, 18 Oct 1997 22:22:45 -0500

WA4VWR just bought a pair of Eimac 3-500Zs (found them in Washington
state) to replace the pair that he had been running since 1974.  Much
to his amazement, when he plugged them in and fired them up, they
drew only 140 ma of resting plate current instead of the usual 190 ma
of plate current that he was use to seeing.

Further, he says that there is a little bit of crossover distortion
on this new pair that did not exist on the previous set.

When I questioned him as to what the manual said they should draw, he
confessed that he has misplaced his user's manual and doesn't remember.
All he remembers is that the previous pair drew 190 ma vrs 140 ma on
the new set; the new set has more crossover distortion; and the new set
does not give him as much power out (by 100 watts) as the old set did.

He wonders if he got a bad set of tubes.  I volunteered to put the info
on the AMP reflector and would relay any e-mail messages to him.

Any experiences, ideas, opinions on this is most welcome.

Thank you and 73,

Rod, N5HV

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