"Steve" wrote in message
...
A while ago I bought a homebrew amp (80-10 meters) that
uses
a single 833A tube. Its beautifully built. So far I have
not been
able to find any plans or schematics for an amp that uses
this
tube. Has anyone seen an article in QST, Ham Radio, or
other
magazine of an amp using an 833A? No luck with a web
search.
TIA
Steve W6SSP
p.s.-it has a tuned grid circuit
Check RCA transmitting tube handbooks of the 1950's to
see if they have recommended operating conditions or even a
sample circuit for using an 833 as a linear.



--
Richard Knoppow
Los Angeles
WB6KBL

So far all commercial applications I've found are as modulators,
not RF tubes. They are supposedly usable to 30 MHz but have
yet to find a real world RF application other than the amp I have.
I'll trace out the wiring and come up with a schematic. Once thats
done I'll be able to figure out how its biased.
Steve

"Richard Knoppow" wrote in message
...

"Steve" wrote in message
...
A while ago I bought a homebrew amp (80-10 meters) that uses
a single 833A tube. Its beautifully built. So far I have not been
able to find any plans or schematics for an amp that uses this
tube. Has anyone seen an article in QST, Ham Radio, or other
magazine of an amp using an 833A? No luck with a web search.
TIA
Steve W6SSP
p.s.-it has a tuned grid circuit
Check RCA transmitting tube handbooks of the 1950's to see if they
have recommended operating conditions or even a sample circuit for using
an 833 as a linear.



--
Richard Knoppow
Los Angeles
WB6KBL

"Steve" wrote in message
...
So far all commercial applications I've found are as
modulators,
not RF tubes. They are supposedly usable to 30 MHz but
have
yet to find a real world RF application other than the amp
I have.
I'll trace out the wiring and come up with a schematic.
Once thats
done I'll be able to figure out how its biased.
Steve

"Richard Knoppow" wrote in
message
...

"Steve" wrote in message
...
Lots of snipping...

833A's were widely used in AM broadcast transmitters
both as finals and modulators of about 500W to 1KW rigs (RCA
BT-1 etc.) and as drivers in higher power transmitters. I've
seen designs for ham transmitters using them but I don't
know if any commercially made _ham_ transmitters did.


--
Richard Knoppow
Los Angeles
WB6KBL

833A's were widely used in AM broadcast transmitters both as finals and
modulators of about 500W to 1KW rigs (RCA BT-1 etc.) and as drivers in higher
power transmitters. I've seen designs for ham transmitters using them but I
don't know if any commercially made _ham_ transmitters did.


--
Richard Knoppow
Los Angeles
WB6KBL


On page:

http://www.criticalradio.com/833%20R...%20Article.htm

you find the diagrams of an AM transmitter using two 833s in parallel (class C),
modulated by a push-pull pair of 833s.

Reducing the grid bias down to about -70V, you may operate the 833s in class B
for linear operation, still grid-driven.

It may however not be easy to maintain the neutralization bridge nulled on the
whole 3 - 30 MHz frequency range, and you may have to switch different
capacitors in the bridge on the various bands.

Alternately, you may try a grounded-grid filament-driven configuration. You
should then keep the filament at about +70V with respect to ground (using a 100W
NPN power transistor with a 70V zener between collector and base). I however
fear it may be hard to drive.

73

Tony I0JX