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Pops 300B tubes on turn on in my Vac

Put a set of carbon plate Sophia's in my Vac70/70 amp.Over the last week on start up a couple of the tubes have sparked on the top of the tube resulting in a "pop"sound.
Is this something i should be concerned about it doesn't happen all the time.The set is brand new.
I don't remember that happening before with my amp.
wavetrader
mechans
3,048 posts
 
I am a complete amatuer but it appears to be arcing which is very serious. Does this happen while playing ? Does any other tube you use do the same. If not I would pull these immediately.
audiofeil
4,011 posts
 
Did you set the bias "low" before installing the new tubes?

When circuits are not self-biasing I always adjust the bias to a much lower setting and then increase as needed when changing tubes.

Good luck.
wavetrader OP
260 posts
 
no, not yet anyway the spark has occured in the back row on the left channel and the right channel also.I have checked the seating of the tubes and they seem tight.I have powererd the amp down and will try again later to power up.Can arching blow my amp or damage it this is a push pull design.

thanks
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