Is there any reason that a glitch resistor is preferred over a fuse in the anode
lead. I opened up my L-7 power supply last night and found that someone
had replaced the 0.82 ohm glitch resistor with a fuse (I was planning to replace
the 0.82 ohm resistor with a 50 ohm 50 watt power resistor as per the
recommendation on G3SEK's website).
----- Original Message -----
From: "Tom Rauch" <firstname.lastname@example.org>
To: "Vic Rosenthal" <email@example.com>; "Ian White, G3SEK"
<firstname.lastname@example.org>; "Phil Clements" <email@example.com>
Sent: Friday, September 07, 2001 5:11 PM
Subject: Re: [AMPS] SB-1000 mods?
> work, but thousands are in use. I have always added
> > Rich's grid fuse resistor scheme when repairing SB-1000's.
> > No tube failures to date that I know of.
> You'd be far better off to use a HV glitch resistor, and leave the grid
> grounded. Resistors in grid leads are bad news unless there is
> good reason to add them, because they let the grid rise to anode
> voltage if there is a fault.
> If the grid rises to anode voltage, the grid naturally no longer
> shields the filament from the HV surge. That means the filament is
> many times more likely to rise to B+ rail.
> Better to simply put a proper surge resistor in the HV lead, and let
> the arc pull the anode low through a series resistance!!!
> 73, Tom W8JI
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