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Author Topic: Age old question: Replacement finals for TS-830S - (JAN) GE 6146W OK?  (Read 6862 times)
G3RZP
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« Reply #15 on: April 20, 2012, 03:15:36 PM »

If nothing else, the heater current for the 6146W is different  (1.25A) to the current for the 6146B (1.125A)
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KE4DRN
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« Reply #16 on: April 23, 2012, 07:57:14 PM »

hi

Don't pay more for matched pair, the kenwood hybrids do not require them.

added: the kenwoods use 6146 in parallel not push pull operation.

http://www.nj7p.info/Common/Tube/SQL/Tube_query.php?Type=6146w

http://www.nj7p.info/Common/Tube/SQL/Tube_query.php?Type=6146b

73 james
« Last Edit: April 24, 2012, 08:39:10 PM by KE4DRN » Logged
G3RZP
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« Reply #17 on: April 24, 2012, 02:56:48 AM »

Over the years 1970 to 1975, I designed and put into commercial production various transmitters that in total, used around 8,000 6146B tubes - some in 2 tube PAs, some in 3 tube PAs. I also measured the performance of a number of tubes (13) from 3 different new batches. For given bias, screen and plate voltages, the plate currents ranged from 4 mA to 28mA. The average was 13mA with a standard deviation of 6mA.

Not as bad as 6JS6s, but setting up for 50mA total plate current for a pair, one could be running about 44mA and the other one 6mA.

Even tubes from the same batch showed a 2:1 spread.

Now because of the relatively intermittent  use - not many people transmit for hours on end - you can get away with it. In an extreme case, you can see the anode inside glowing. But personally, I don't like it, and prefer either matched tubes or a separate bias pot for each tube.
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