[AMRadio] 860 tubes used as modulator output tubes

Bob Deuel k2glo at jkasystems.com
Tue Jul 29 00:49:12 EDT 2014

I desire to use a pair of 860 tubes as modulator output tubes in a special
homebrew transmitter project.  I am aware that tetrodes are not the best
choice for use in a modulator and especially a lowly inefficient 860, but
that is the tube that is most physically fitting for this particular
project.  I am also aware that using the 860 will require an added screen
and bias supply and a substitution of a triode or its sister 852 triode
would be better choice but those are not options and the extra power
supplies are no problem.  I cannot find any information on anyone using a
pair of 860's in a modulator and obviously no manufacturer's published
operating specifications as an AB modulator.  Have any of you used PP 860's
in a modulator either as tetrodes or  triode connected tetrodes?  Any
thoughts and information on suggested operating perimeters would be helpful.


Bob, K2GLO

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