Gents,
HV safety resistors absorb glitches of the amplifier tubes,
such as internal arcs. In such a situation the resistor may
be absorbing the entire stored energy of the power supply
filter and attempting to dissipate it as heat, which is
the cause for many explosions.
After reading AG6K's articles about this device, and by
observing the quality of devices employed in commercial
amplifiers it was decided to use a 225 Watt, 25-Ohm
wire wound that resembled a cookie-cutter with wavy
windings in my latest project. The power supply uses
50uF at 5KV capacitance and is rated at 3.0A CCS.
The resistor is located in the power supply cabinet
and away from any delicate stuff, so if it did explode
little else would be damaged by grenading porcelain.
If you choose to use a vitreous enamel wire wound
resistor of whatever value, please make sure it's
mounted in such a way that if it did explode it will not
destroy tubes, vacuum caps, vacuum relays, etc.
Some folks surround this resistor with a cane metal
(perforated) enclosure.
Hal
W4HBM
>
> Hv safety resistors are in place to protect the tube or tubes not
> the
> diodes, who cares if a diode block goes compared to the price of a
> tube. I
> have a 25W resistor in series with the B+ explode, wonderful fuse
> the tubes
> survived, and so did the diodes. 73 Sam KF4YOX
>
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