2. amps-preamps
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Disappointing short life of NOS preamp tube

Being sarcastic really.

I only got 7 years out of  50's 12au7 RCA black plate. That may indicate 5 more randomly futzing out the rest of this year.

With the state of tube pricing now, tubes definitely not on my list of unnecessary audiophool spending.

I was really hoping these things going for 20, especially them just being preamp tubes, not a power tube. Fortunately, I have one more for backup, plus the 6 stock tubes in the shoebox.

Such is life. I'm more impressed by my relatively quick troubleshooting, avoiding severe neurosis. Less than 5 minutes-patting myself on the back, and praise from the boss.

.

tablejockey
audioman58's avatar
audioman58
3,832 posts
 

7 years is a long time for any tubes , plus you don’t know how your amp company bias the voltage or run the Ma voltage , power tubes 3-4000 hours 

small tubes like Tele , Siemens are 10,000 even bendix,  some ge 5 stars are tough military speck,  but nothing guaranteed with tubes , todays tubes far worse.

jpmanomet
36 posts
 

In 2003 I ordered three NOS Mullard CV4003 (12AU7) for the preamp I was building. Average about 16 hours per week for roughly 16000 hours to date and still going strong. I tested all my tubes last month and these three still have close numbers. I have a backup set of Sylvanias that I'm not sure I'll even need in my lifetime. 😀

senza
80 posts
 

I always calculate tube’s hours of use . That’s the base. 

fatdaddy2
367 posts
 

my tube is older than your tube, my tube is older than yours...

dinov's avatar
dinov
788 posts
 

I hope I get seven years from all my NOS tubes…..

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