James Tolar w5sqe at INAME.COM
Wed Sep 18 16:56:05 EDT 2002

 I think I unintentionally misled some of you who read my request for a 50hy @ 0.5A heising choke. Actually it is no more than a normal choke (a little larger than usual) that is to be used in a hybrid heising circuit, not the traditional type. I will build a normal Class AB1, pair of 813s modulator, with a UTC CVM-4 mod xfmr. I will couple the mod xfmr to the choke thru a 2ufd, 4kv capacitor. The HV B+ will feed the bottom of the choke, and the other side of the choke will go to the plates of the pair of 813s in the rf amp. The purpose is to keep the DC out of the mod xfmr secondary, to prevent satuation, and thus not to contribute to audio distortion. The basic circuit is shown on the "amwindow" web site, and is attributed to K1JJ. This method of plate modulation is, or was, used by AM broadcast stations. I can accomplish the same by seriesing several smaller chokes.
Jim   W5SQE
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