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The safe way to change valves?

PostPosted: 17 Feb 2012, 10:57
by Fiesta red
After reading the previous thread about new valves and possible electrocution. Can the experts here give some advice on how to change amp valves? I am sure many of us would benefit from good sound advice (pardon the pun).. My first question is,leaving the amp plugged in but switched off,does this earth the amp? Do I need to wear my wellingtons whilst caring out the procedure? lol
Ken...

Re: The safe way to change valves?

PostPosted: 17 Feb 2012, 11:22
by keithmantle
Hi Ken, I always unplug my amps and leave for 30 mins before a valve change, one point wear plastic/rubber gloves as oil in the skin can be transferred to valve glass and can cause cracking/breaking, don't replace back panel until the amp is tried out, and don't start poking fingers in/around while amp is still switched on for any reason !!.

Re: The safe way to change valves?

PostPosted: 17 Feb 2012, 11:55
by leddo
And always always always give the valves plenty of time to cool down before you touch/change them. I found this one out the hard way. Ouch.

Re: The safe way to change valves?

PostPosted: 17 Feb 2012, 14:10
by RogerCook
Good advice above. Valves do get hot and amps often do retain a high voltage after they've been switched off. However unless you touch the exposed metal pins on the bottom of the valve while they are still in contact with the socket you won't be in exposed to that.

When removing a valve try to pull it out straight with only the minimum of wiggle to get it free. When you install new ones make sure all the pins are straight and that you line them up with the appropriate pattern on the valve holder (trickier with skirted valve holders) or you could end up with bent/broken pins and the valve connected wrongly. Push them in firmly so the pins are fully home and replace any retaining clips and screen cans.

If in doubt take it to an amp tech

Roger

Re: The safe way to change valves?

PostPosted: 18 Feb 2012, 10:44
by Fiesta red
To the above,thanks for your advice. Ken..