tube info
https://upscaleaudio.com/pages/tube-basics-and-frequently-asked-questions
excerpt
Power tubes like EL34’s and KT88’s are good for about 2500 hours or more. But may go longer in an amplifier with a conservative design. Small signal tubes with numbers like 12AX7, 12AU7, and 6922, and rectifier tubes like 5AR4 may go 10,000 hours.
My experience: they last a hellofa long time.
I test new matched tubes when I receive them, and mark the date and number reached on the meter on the box, confirming just that (and no short). Then I check them annually, around thanksgiving, ready for the holidays. less power on the meter? still ’matched’? typically the same as new, a very gradual decline. Very rarely a short, which you typically find when things start sounding bad, iow, find the one that ’blew’.
My system sounds very good after 20 minutes warm up, listen for a few hours, and I turn them off until next which will be several hours later or the next day. Maybe avg 15 hrs/wk, i.e. 800 hrs/yr. They last for many years, most of my McIntosh mx110z’s were tested good again by Audio Classics this spring. They confirm my thinking, MOST are original tubes. Ryan said "these old tubes last nearly forever".
I cannot understand having tube equipment and not having a simple tester to rule out problems/have confidence/find problems. Just because it was a great find, I bought an Accurate Instrument 257. I just tested my preamp and power amp, using prior 157 and new to me 257. They all reached the same #’s on both unit’s meters. I have a big fancy one, I forget, Jackson or Hickock, the ’toy’ ones always show the same as the big one, I don’t bother with it any more.
I have a large collection of old tubes, used and new. Almost every used tube I test measures ’good’ and reach #’s on the scale equal to or just below new ones. Of course I have found bad ones, but not that many.
Way back when, going to the store to use their big professional testers, I took all the tubes from my Fisher President II, every thanksgiving, AM tuner; FM tuner; Master Control Panel, pair of tape preamps, FM multiplex, pair of RIAA preamps (Fisher came to my uncle’s NYC apt and converted the TT to MM), pair of Mono Amps. Stood there until my feet and back hurt, impatient line behind me: maybe found 2 I decided were ’weak’, a rare ’bad’.
https://upscaleaudio.com/pages/tube-basics-and-frequently-asked-questions
excerpt
Power tubes like EL34’s and KT88’s are good for about 2500 hours or more. But may go longer in an amplifier with a conservative design. Small signal tubes with numbers like 12AX7, 12AU7, and 6922, and rectifier tubes like 5AR4 may go 10,000 hours.
My experience: they last a hellofa long time.
I test new matched tubes when I receive them, and mark the date and number reached on the meter on the box, confirming just that (and no short). Then I check them annually, around thanksgiving, ready for the holidays. less power on the meter? still ’matched’? typically the same as new, a very gradual decline. Very rarely a short, which you typically find when things start sounding bad, iow, find the one that ’blew’.
My system sounds very good after 20 minutes warm up, listen for a few hours, and I turn them off until next which will be several hours later or the next day. Maybe avg 15 hrs/wk, i.e. 800 hrs/yr. They last for many years, most of my McIntosh mx110z’s were tested good again by Audio Classics this spring. They confirm my thinking, MOST are original tubes. Ryan said "these old tubes last nearly forever".
I cannot understand having tube equipment and not having a simple tester to rule out problems/have confidence/find problems. Just because it was a great find, I bought an Accurate Instrument 257. I just tested my preamp and power amp, using prior 157 and new to me 257. They all reached the same #’s on both unit’s meters. I have a big fancy one, I forget, Jackson or Hickock, the ’toy’ ones always show the same as the big one, I don’t bother with it any more.
I have a large collection of old tubes, used and new. Almost every used tube I test measures ’good’ and reach #’s on the scale equal to or just below new ones. Of course I have found bad ones, but not that many.
Way back when, going to the store to use their big professional testers, I took all the tubes from my Fisher President II, every thanksgiving, AM tuner; FM tuner; Master Control Panel, pair of tape preamps, FM multiplex, pair of RIAA preamps (Fisher came to my uncle’s NYC apt and converted the TT to MM), pair of Mono Amps. Stood there until my feet and back hurt, impatient line behind me: maybe found 2 I decided were ’weak’, a rare ’bad’.
