[gadfly]

Frank et al.  Just read a post on computeraudiophile.com where the
claim was made that, "Tubes and lightbulbs last longer if the filaments
are left on all the time.  That's just a fact.  Thermal cycling is the enemy
of filaments."  Any validity to this claim as regards say a fet valve CF
preamp  having longer tube life if left on all the time assuming my
current use pattern is turning it on and off two times a day?

thanks,

gad-

[Lefty052347]

It seems to me that leaving tubes on 24/7 will require more frequent tube purchases than 4-8 hrs of use with them turned off the other 16-20 hours. 

Regards,
Dean

[avahifi]

Heat is the enemy of electronic components!

That old 'leave tubes on all the time' folklore dates all the way back to the 1940s when the first computers used had about ten thousand 12AX7 tubes packed in banks and banks of interconnected circuits.  Back then,if they turned this monster off, they were nearly sure to loose a couple tubes at the next turn on and have the terribly job of finding the failed tubes in the forest of hot glass.

On all the time wastes energy, eats up the service life of all the parts, and serves no useful purpose. We have yet to see a field failure of a tube in a Fet Valve CF preamp.  Turn on is slow and gentle by design so please just turn the equipment off when you are not using it.

Frank