Pro-tek 811A

[Bob Meyer]

I have found out PRO tek 811A tubes are made in china.
not very good tubes.
I have 8 china 811A tubes here.
from looking at them all I see in horizontal mounting they 
are not lined up inside.As much as 90 deg. twist in plate.
The filament looks ok.has springs to keep it in place durring heating.
The grid looks ok.
The plate is the cheaper kind.not black plate like 
my 811A JAN USA.

Testing them I find emission's vary from tube to tube.
I did the best match I could.
with 4 811A china tubes in a amp I find out that
they run un-even and get a little red on one tube.
at max. ICAS power 1KW plate input.
They sound ok,
I doen't think they will last very long.

I did try to buy SVETLANA 811A
but no longer make.
They still make the best 572B at a price!!

73's
Robert Meyer

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