[Boatanchors] 6146 vs 6146A vs 6146B or 6146W
pulsarxp at embarqmail.com
Tue Jul 5 03:25:20 EDT 2011
I just scrutinized the spec sheets for the above mentioned tubes. They are
6146, 6146A, and the 6146B or newer 6146W tubes. The spec sheets show the
6146B and 6146A interelectrode capacity to be virtually the same and the
6146 tube to have 1/2 pf more input capacitance. So for practical matters,
the interelectrode capacitances are the same for all these tubes.
The tube spec/charts also show they all can be run as plate modulated class
C amplifiers with 600 volts on the plate, 250 volt grid voltage on grid 2,
and -150 volt negative voltage on grid number 1. Yes, the 6146B shows the
glass envelope can run at a higher temperature then the others and the plate
current can be increased from 125 ma to 250 ma. when using the 6146B or W.
The number 2 grid still has a max of 2 watts and the grid current is the
same for all. That is 4 ma.
I have plugged in many 6146B tubes in my old boat anchor rigs which
originally were supplied with 6146 or 6146A tubes. I have never had a lick
of a problem when ever I have done so. Since my transmitters were designed
for the 6146 power ratings, I have never "pushed the rigs to give the max
6146B power output by increasing the plate current. I think that would be
unwise. (The exception to this is my Collins S-line equipment which were
built for 6146B tubes or at least came out of Collins with the B tubes
That said, to be honest, I think the talk about B tubes not working in A
tube transmitters is a bunch of BS or falsehood as I have never experienced
the horror story myths I have read about B tubes from time to time. I base
this upon the spec sheets and the fact I have never had a problem
substituting an A tube with a B tube. As I mentioned earlier, I have never
"pushed" the rig beyond the A tube ratings after installing a B set of
I am well aware of the WARNING given about using a B tube in place of A
tubes by one individual. (I am not trying to slam him but I do disagree
strongly with his paper. I don't know anything about using these tubes in
VHF applications but only in HF applications). All I can say is, the spec
sheets point out you can replace an A tube with a B or W tube and I have
never had a problem doing this. I've done it enough times without a problem
and based on the spec sheets, they indicate no reason for having a problem.
Another good ham friend of mine has used the B or W tubes enough times too
and he too has never had a problem with the substitution.
Today, in 2011, new 6146B and 6146W tubes are sure a lot easier to find then
6146 or 6146A tubes. I've also been able to buy NOS military 6146W tubes
for less money then NOS 6146 or 6146A tubes. I can buy new W tubes for
about the same or less money then used 6146 or 6146A tubes.
I am writing this so others who may have a fear of using a B or W 6146 in
place of a 6146 or 6146A tube should try it and find out for yourself what
is fact and what is fiction.
Am I alone with never having a 6146B substitution problem? I'd sure like to
hear from others who have done the switch. Have you personally ever had a
problem doing this? The spec sheets say you should have no problem and I
have had none myself.
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