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Tube Life Question: 12AX7 Drivers

Hello.

OK, here's a question for some of those out there who have lived with 12AX7 drivers. How long have they lasted in your experience? I used to have an amp that used them, and after 6 years, they still seemed fine. Now that I again own an amp that uses these tubes in this application, I'm wondering what the actual life expectancy is - 5 years, 10 years, 25 years???

Thank you in advance,
Joe
trelja
ben
66 posts
 
12AX7 driver tubes in my amp (SEP Class A circuit)5-6 mounths last (3-4 hours listening a day)they are EH 12AX7s
preamp tubes are 12AU7 and power tubes are KT88 and they last
atleast a year but driver tubes getting dull,dry and lifeless
in 6th mounth. I do not know why?
trelja OP
3,223 posts
 
Ben, not to be a wiseguy, but you might want to check either the guy you're buying tubes from, the bias settings on that amp, or what the voltage coming out of the wall actually is. Honestly, you are seeing probably the worst tube life I've ever encountered.
ben
66 posts
 
Trelja,thanks for your help, my amp is auto bias, though voltage is not bad I use power regulator,the only logic reason
left is the tubes I have bought EH12AX7 s were bulk version and they might be terrible short life,I will try to buy original box version.
mechans
3,048 posts
 
Ben what you describe as dull.dry and lifeless others might perceive as burn in. Try the Sovtek LPS it might be right up your alley and are supposed to be quite rugged.
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