I guess I missed the original message. However, if you are talking about the
maximum plate voltage on the 6146 tube then the maximum plate voltage is 400
volts ONLY when the tube is being used as a modulator in Class A. When used in
Class AB-1 or AB-2 the maximum plate voltage for a 6146 tube is 750 volts.
When used as a Class C plate modulated stage then the maximum plate voltage is
600 volts. When used as a Class C amplifier for FM or CW then then maximum
plate voltage is 750 volts. This per the RCA specifications sheets dated May
1, 1952.
For the 6146A/8298 tube there is no recommendation for use as a Class A
modulator. However, for all other applications the maximum plate voltage
listed is the same as the original 6146. This per the specifications sheets
dated May of 1963.
Now the maximum input power to a single 6146 or 6146A/8298 is 90 watts for
Class C telegraphy, 85 watts for Class AB-1 or AB-2, and 67.5 watts input when
plate modulated.
For the article on the 6146 family of tubes that appeared in Electric Radio a
while back (and has been republished in several other places since then) go to
http://k9sth.com/uploads/The_6146_Family_of_Tubes_1.pdf
Most of the commercially built amateur radio transmitters that used the 6146
family of tubes (from the 1950s through the 1980s) run at least 750 volts and
in many cases well over 800 volts on the plates of the 6146 tubes. There are a
few examples that run closer to 600 volts but those are in the minority.
Glen, K9STH
Website: http://k9sth.com
--- On Thu, 8/6/09, Bill, W6WRT <dezrat1242@yahoo.com> wrote:
However, your example of 600 VRMS on the plate of a 6146 grossly exceeds the
manufacturer's ratings. RCA rates the 6146 at 400 VDC absolute max, which
corresponds to a RMS max of about 280 V when properly tuned. I realize your
example was just for discussion but we might as well discuss real world. :-)
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