Power Tube Failure

@mulveling  great, and useful, stories... thanks.  They convince me that I really should consider purchasing a tester.

@elliottbnewcombjr I looked all three - great stuff.  Certainly appeals to my geeky side. 

Having never used a tester, I am wondering how I can you confirm if any (or all) of the testers measure ALL of the key parameters - resistance? transconductance? amplification? microphonics? 

Any thoughts?

(I realize that is a novice question, but I am not clear if different manufactures call one parameter by different names, etc.  Most of the photos lack enough information.).

Thanks in advance

Upscale Audio has extensive information for vacuum tubes on their website.  They said that tubes usually last much longer than the number of hours that the manufacturer indicates and UA recommends against replacing them prematurely, which would be a waste of your money.

I had a tube fail on a Primaluna preamp a few months ago.  It blew a fuse, which prevented any further damage.  I replaced the tube and the fuse, and everything is fine.  The current Primaluna models have indicators that show when a tube is wearing out.

@78sman "Primaluna models have indicators that show when a tube is wearing out"

Wow, I could have had a V8!

For the younger readers, that means - Dam, I wish I thought of that! ;-)

I also wish my Preamp had that feature.

Op , are you referring to one of the four 12AX7’s in your Zesto Andros phono pre ? When a tube looses its seal or cracks the incoming air causes the tube to turn white. I’ve had this happen twice with power tubes without causing any damage. The glass cracked ( I assume from heat and age ) and this causes the tube to fail. Just like when a lightbulb fails. If your phono stage has a fair amount of time I’d just put 4 new tubes in it. I’d also ask Zesto this question for a more accurate answer. I have had power tubes fail and damage my amp and the tube had no visible damage. It was only identified while on a tube tester. You might look up your local short wave / ham radio club for help with testing. My friend is a musician and has one of the modern “ Orange “ testers and I’ve borrowed that with good results. Best Wishes , Mike B. 

@buellrider97 

Thanks for the information.

I am only referring to the power tubes. I have one in my PreAmp.  

Yes, the impetus of this question was the loss of a tube in my Phono Preamp, but I am not very concerned with possible damage of low-amp tubes like the 12AX7s.

Also, good to hear about your success with the 'Orange' tester.  I am window-shopping for a tester, but need to better understand the limitations of each. 

Best,