[Amps] 3-500 to 4-250 tube conversion

Tom Osborne w7why at frontier.com
Thu Feb 16 09:29:53 PST 2012


6 3-500's??

What the heck band is this made for?  73

Tom W7WHY


> hello. recently I received an amplifier with 6 bad 3-500z tubes in it. i
> have a bunch of good 4-250 and 4-400 tubes on hand and am looking to
> convert the amp to run on these tubes. the cost of purchasing 6 new 3-500
> tubes is out of the question at this time. the amp covers 10 - 80 meters.
> looking at the tube data it looks like all i need to do is strap pins 2
> and
> three together with a low ohm resistor and that should do the job, one
> being a triode and the other a tetrode. the power supply seems more than
> adequate. any schematic help or other information will be greatly
> appreciated. thanks ke5rgm 




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