[AMRadio] too much HV Fin.

[ne1s at securespeed.us]

> Well, as I said, always have found this to be true and realize that the
> lower voltage drop across silicon diodes versus a HV rectifier is the
> reason, but the theory of how much it should change never seemed to work
> out.  In the winding down tube era, every mod kit I put in a commercial
> tube receiver came with a resistor in the 560ohm 10 watt range, current
> draw dependent of course, to offset this higher voltage.  In the HA10, the
> real culprit that I overlooked is the missing swinging choke, so all I
> have is a cap input filter where the cap is charging towards the peak of
> the DC from the rectifier while under the bleeder resistor and 811 idle
> current draw which apparently is not enough to limit the HV to something
> more comfortable for standby 811's.  In Bill's case, as noted, he just may
> have a shorted choke.  We'll check that out.
>

I don't remember anyone pointing out that a choke input filter requires a
minimum load, usually supplied by the bleeder resistor, or it will "look
like" a capacitor input filter. So if the bleeder resistor has gone high
in value, that's another possible cause of the symptoms described.

I know the supply in question is now using SS diodes and not MV tubes, but
if you plan to use MV tubes keep in mind they generally become VERY
unhappy if looking into a capacitor input filter - they demand a
choke-input filter,

73/GL,

-Larry/NE1S