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Howdy,

Thanks for the reply

Well, since the voltage across the choke is dependent on the current through the choke, it shouldn't make any difference. Position of the choke in the circuit, positive or negative doesn't really affect the voltage "across" the choke.? It only changes the actual voltage on the windings referenced to the grounded iron core

Putting it in the negative lead would only take the high voltage off the windings (which is certainly desirable).... but I don't think the "snapping" is due to "winding-to-core" arcing.? If it was, it would likely be continuous.? I.E., it would short, stay shorted and pop the fuse.?

This is more a "clicking", snapping", ticking that I think is due to internal arcing across windings (or the arc "gap" depicted in the schematic) and that voltage is directly related to the (pulsating) current in the windings.


Either way, my original question is more related to the the idling current when the amplifier is in the STBY mode.? (I know what it should be in the transmit mode.....It should be around 120ma, and that's more than enough current for the choke)

And in fact, I went back to the manual and read a little closer and actually found what I was looking for!



I guess I should just RTFM? before asking questions!!? But at 40ma, I'm thinking it's not going to be enough unless I add an additional bleeder.

I found that using only the power supply bleeder resistor of 210k Ohm (with only an 18ma draw) , the voltage was high at around 3750+ volts.? (and there was "ticking")?

When I added an additional 100K in parallel,? I still had around 3750+ volts ,? total resistance around 68K,? resulting in a total 55ma draw (still ticking!!)

When I added an another 100K in parallel, I saw a significant voltage drop.? Voltage was 3460v, no ticking, with a combined resistance of about 40K.

Total current draw due to the total 40K (210K + 100K + 100K parallel) was around 86ma.

I know choke input power supplies have a lower limit of current that must be present to prevent the voltage from "soaring" (ARRL handbook term!)

The part that I am concerned about is that since the tube will draw 40ma (according to the instruction above) when the T/R "jumper" is removed, that's only going to be a total of about 18ma + 40ma? =? 58ma.

If you note above that I still had "ticking at 55ma, I am having a hard time believing that 3 additional ma will be the "break-point" of where the choke starts to "choke"

Maybe it will.?? This is where my lack of experience with high voltage (swinging) choke input supplies is somewhat lacking.?

I would REALLY like to hear from someone else that actually has or has played with one of these power supplies hooked up to an HT45? so I can compare notes!