Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => AmpTools/Tech Tips => Topic started by: supro66 on March 05, 2009, 10:33:56 am

Title: Discharging Filter caps
Post by: supro66 on March 05, 2009, 10:33:56 am

I know there is a tool to discharge the Filter caps.

I know it is just a resister on a stick

What size resister


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Title: Re: Discharging Filter caps
Post by: jhadhar65 on March 05, 2009, 11:42:17 am

I think I use a 150R/10W.  I took an old meter lead (1000V wire) with the pin probe, added the resistor in the middle with shrink sleeve, then replaced the meter connector with an insulated alligator clip.  Works like a charm and doesn't even hint at getting warm.

Title: Re: Discharging Filter caps
Post by: Geezer on March 08, 2009, 02:46:16 pm

I use 500R/10W.

FWIW, you don't have to use any stinkin' resistor   ;) ....your amp already has "discharge" resistors installed!
Simply clip an alligator lead to ground, then clip the other end to a V1 plate...the voltage has to pass thru all the B+ rail dropping resistors, thus limiting the "spark" potential. The voltage is usually down to safe levels in <1 minute (probably much sooner!)

$0.02
Geez'r

Title: Re: Discharging Filter caps
Post by: birt on March 08, 2009, 05:42:04 pm

i use a big resistor too. i guess 600ohms 75 watts :p
it has strandedthick wire on both sides. one side has a probe, one has a clip. the resistor has shrink sleeve around it. it's basicly what i had lyring around when i needed the tool.