>
>I noticed that on some 8877 amps they tie the cathode to one side of the
>filament, then feed the cathode bias into the filament. What is the purpose
>of doing this, rather than letting the cathode float?
? To avoid the possibility of breaking down the fil./heater insulation
during a glitch.
Another problem is that If a heater/cathode arc takes place, it is
possible that the heater wire can be severed.
>
>I also notice the same practice with AB1 tetrodes, i have tried both methods
>and they both seem to work. Is there some sort of secret to all this?
>
>I would like to know since i am building a new 220mhz 8877 project.
>
? Above 30-MHz, the heater is tied to the cathode, and the heater is fed
through a choke. .
>
- later, Bill
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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