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Re: [TCML] 833C versus 833A vacuum tube

Hi Steve,

Been a while...

John and Jim gave some good info.

I am in the camp from what I have read in Eimac literature, that orange is
ok and good occasionally for getter action, to help maintain a hard vacuum.
A lot of old tube data will say dull red. Transmitting tubes are different
than other tubes. Which are sometimes referred to as power tubes. But I
personally think they really meant orange. Yes, really red is bad as John
says. Seen some fool a few years ago, on YouTube intentionally destroy a
pair of 3-500ZG's with graphite plates in HAM linear amplifier. Went
orange, then red, really crazy red, then oh yeah...tube pin seals gave out
from extreme heat...so even more gas than out gassing of materials...

I also think, repeatedly cycling really red is hard on tube pin seals,
weakening the bond, a bit at a time.

Occasional very short duration of red is ok. Just be short...and don't do
it often. Tube pins seals come into play as I said above.

I run my 304 heavy orange all the time.It has a tough tantalum metal plate.
Been red occasionally, but I don't do very often. Usually on accident.
Actually I don't think I could ever actually melt this, as I said seals
would give out first...

Originally on the 304er coil I used to run a T-200  tube, which had a
graphite plate, and I did not hesitate to run it orange all the time.

Graphite does definitely have some advantages in short overload conditions,
that would yes melt a plate as in your 833A. I have melted a hole in the
same makeup of plate material myself in a different tube.

Just my 2¢ on this topic.

Chris Reeland
Ladd Illinois USA

Sent from my LG V20
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