Hey Jim, don't be so quick to discount those ceramic tubes such as the
8877 and 3CX800A. They will have "floozy grids" for operators that don't
know how to use them properly. I have an alpha 86 with a pair of
3CX800A7 and an alpha 9500 with single 8877 which I've used for many
years. The trick with those tubes is to make sure that you don't draw
any or very little grid current. On both of my amps I only see a flicker
of grid current if any at all. Just my 2 cents worth and I'm sticking to it.
Fern VE7GZ
On 07/12/2022 10:27 a.m., jim.thom jim.thom@telus.net wrote:
Don't even think about installing CHINESE 811'a horizontally into any
30L1. Cathodes will sag..and short. The only thing that will work in a
30L1 is chinese 572B's.
Chinese 811's are piss poor at the best of times, they don't hi-pot test
very high. Typ on ameritron AL-811 amps, 572B's are used for tube
replacements.
Rob nailed it. Stick with old school 3-500Z amps. They are very easy to
maintain, and easy to modify and upgrade. Stay away from megabuck tubes
like 8877, 3CX-800's etc. Both have floozy grids, and require grid
overcurrent protection. I would stay away from russian tetrodes and
triodes as well.
Jim VE7RF
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