[sdiy] Tube amp cap discharge tool?

[Ken Stone]

A common bleeder value is 470k, but it takes a long time. Personally I
prefer to use a 1k5 5w resistor (per rail) that is switched across the caps
as needed. The discharge is pretty quick, allowing you to get on with
working on the unit. If it is something you will be doing often, use a relay
powered from the heater rail to disconnect the bleeders when the unit is
running, and reconnect them as soon as power is removed.

Ken


>Best thing is to put bleeder resistors across the caps *permanently*. 
>Say 33-100k or so, power handling depending on the voltage P=U²/R. Then 
>you can always work safely after a couple of minutes (tau=R*C, takes 
>several tau's until the voltage is safe though). The thing is that high 
>voltage caps can charge them selves up again, due to dielectric absorption.
>
>Cheers,
>  René
>
>-- 
>uzs159 at uni-bonn.de
>http://www.uni-bonn.de/~uzs159
>
>
>
_______________________________________________________________________
Ken Stone   sasami at hotkey.net.au or sasami at cgs.synth.net
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>