[Hallicrafters] HT-33 Plate Current Dip Question

PETER A. STRATIGOS peters7 at mindspring.com
Wed Feb 4 13:29:31 EST 2004

I am in the processing of bringing up a HT-33, the unit using two 4CX300As as finals.  The gird tuning adjustment shows upwards of 100 ma of increase as I adjust the grid tuning.  However, when I attempt to adjust the Plate Tuning for a dip, per the manual, I detect barely a 10 ma dip, if that.  Even though the plate current dip is very slight when running 400 ma, the power output increasing to roughly 350 watts our with about 2 watts in on 80 meters.

Tuning based on the dip is very difficult.  Does anyone have any experience tuning one of these amps and can advise of the type of dip I should be seeing and also what I should expect in the way of output with a new set of 4CX300As?  Finally does anyone have any thoughts on using 4CX300Ys in place of teh 4CX300As?  The Ys seem to be able to handle a little more plate current but also have a somewhat different plate capacitance?

Many thanks in advance for any help anyuone can provide.


Peter N9HXW

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