>I am replacing the filter cap in the hv section of my Thunderbolt. I will
>be using 2 caps in series. The power supply filter is the choke input type
>using a swinging choke. It supplies 2200 volts. Do I need to add equalizing
>resistors across each cap.
? I would. It's a reliable way to bleed off the caps, plus it applies
equal V to each.
>Depending on who I talk to, Ive been told I do
>need them and than again I dont need them. Which is correct. If I do need
>them, what size should they be. 100k at 10 watts is what Ive been told.
? 10W, 100k? resistors are not ordinarily able to handle even 1000V -
even though that's 10w [read the fine print in the specs]. Also, 1100V =
12.1W @ 100k?. My guess is that whoever told you this does not have a
firm grip on Ohm's Law.
? Also, a swinging choke filter works ok with AM-linear service because
DC current drain is constant. However, for SSB, the current is not
constant, so, if one checks transient regulation with a DC oscilloscope,
it is not ok, This is why Henry, Collins, Harris and the rest never use
a swinging choke filter in their linear amplifiers. For good transient
regulation, either a resonant-choke filter or a capacitive filter are the
only games in town.
cheers, Bill
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
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