>
>On Sun, 31 Aug 1997 07:08:12 +0200 lars.harlin@pocab.se (Lars Harlin)
>writes:
>>Have followed the discussions abt VHF parasitics on the reflector and
>>other media. Has anyone tried using ferrit in a suppressor?
>>
>>Lars / SM3BDZ
>>
>
>The only amps I am aware of were the Heath SB-230 ...
In the SB-230, the ferrite bead is only in series with the HV-RFC. It is
not in series with the anode's VHF-resonant circuit - i.e., the circuit
which supports oscillation.
> ... The Heath was a disaster and blew many tubes.
Amen, Carl. With no VHF suppressor in the anode's VHF-resonant circuit,
the life of a high VHF gain tube is often brief. The AL-1500 is another
such amplifier. A number of owners told me that their's went through a
number of 8877s during the first year. One of them discovered the
seemingly-bizarre technique for making some gold-sputtered 8877s useable.
Rich---
R. L. Measures, 805-386-3734, AG6K
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