2. amps-preamps
  3. 177376-1660

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
petg60
1,486 posts
 

Fortunate that your pre is not pushing tubes hard, considering also the on off cycle.

Sad moment when they go and wonder if the new pair will sound the same.

 

 

audioman58's avatar
audioman58
4,141 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
383 posts
 

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

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