Now This is What I Call A Tube Lover

Understood. Just a conundrum I've been thinking about for a long time with testers. Even now when testing at more real world voltages. I like cj's method (and I assume others like ARC must do something similar) the most: test the tube in the actual circuit -- after burn in -- and see if the circuit performs as spec'd.
 
Myles B. Astor said:
BTW I really am dubious about the usefulness of tube testers except for matching or noise (caveat I haven't played with the Maximatcher or amplitrex). I usually use for small signal tubes the long out of production Kaye tube tester. And with the ones I've tries, tubes that obviously had lots of hours on them and were sounding dead still measured good. So what gives?
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Myles-That's an interesting question. If the tubes measure 'good' on a tester but sound dead, I would suspect the tester is far out of calibration and is measuring cathode emission incorrectly. The life of a tube is dependent on the cathode being able to emit enough electrons to have a strong beam of electrons flowing to the plate (anode) of the tube which means it will have sufficient cathode current to meet the spec for that particular tube. As the tube ages and the cathode current weakens, the tube will not sound good as the electron emission is too low and it will be weak and sound weak. That particular channel will have lower power than the other channel assuming the other channel has good tubes.

'Perfect' tubes should always die a natural death due to the cathode wearing out and no longer being able sustain sufficient electron emission to allow the tube to work correctly. Unfortunately, many tubes become unusable due to other factors such as internal shorts, gas, microphonics, etc.
 
mep said:
Myles-That's an interesting question. If the tubes measure 'good' on a tester but sound dead, I would suspect the tester is far out of calibration and is measuring cathode emission incorrectly. The life of a tube is dependent on the cathode being able to emit enough electrons to have a strong beam of electrons flowing to the plate (anode) of the tube which means it will have sufficient cathode current to meet the spec for that particular tube. As the tube ages and the cathode current weakens, the tube will not sound good as the electron emission is too low and it will be weak and sound weak. That particular channel will have lower power than the other channel assuming the other channel has good tubes.

'Perfect' tubes should always die a natural death due to the cathode wearing out and no longer being able sustain sufficient electron emission to allow the tube to work correctly. Unfortunately, many tubes become unusable due to other factors such as internal shorts, gas, microphonics, etc.
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I don't know Mark. I have three testers and while we could argue about the Hickok accuracy, I think the George Kaye is pretty accurate.
 
Geeez.. I had the Ja-200 and them were enough tubes for me. I love humongous amps but this is too much trouble for me .
The Jadis amps from Ja-80 and forth , come with a light that shines when a tube is dead and that is very helpful . Them can work with one or more pair of tubes out so if one tube is bad you only will notice less power but not noises.

Nice pictures and system .
 
lag said:
Geeez.. I had the Ja-200 and them were enough tubes for me. I love humongous amps but this is too much trouble for me .
The Jadis amps from Ja-80 and forth , come with a light that shines when a tube is dead and that is very helpful . Them can work with one or more pair of tubes out so if one tube is bad you only will notice less power but not noises.

Nice pictures and system .
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They have a warning light for the output and small signal tubes?

BTW, there are 32 more tubes in the four block JP500 preamplifier that isn't shown. Since no one wanted to guess, there's 176 + 32 for a grand total of 208 tubes. Retubing probably costs more than many amplifiers! :)
 
Myles B. Astor said:
They have a warning light for the output and small signal tubes?

BTW, there are 32 more tubes in the four block JP500 preamplifier that isn't shown. Since no one wanted to guess, there's 176 + 32 for a grand total of 208 tubes. Retubing probably costs more than many amplifiers! :)
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I can image the cost to replace the tubes in just one JA800 and this young man has a few of them

Tubes per channel: 12 x KT90 - 1 x ECC83/12AX7 - 3 x ECC82/12AU7.
Tubes per Power Supply: 4 x KT90 - 2 x EF86.
 
The Ja-200 warns only on the output tubes.

Yes the JP-500 comes with another bunch of tubes. I have the jp200 mc and them use a lot of tubes and a lot of room too. This post recalls me that my closet need an urgent cleaning out LOL... :) .
 
lag said:
The Ja-200 warns only on the output tubes.

Yes the JP-500 comes with another bunch of tubes. I have the jp200 mc and them use a lot of tubes and a lot of room too. This post recalls me that my closet need an urgent cleaning out LOL... :) .
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How is the JP500? Does it come with a built in phono stage or do you have to add an external unit? I remember 20 years ago, the old JP80 (?) being a really great phono preamplifier with gobs of gain back in those days. (one of my friends who was also a digital manufacturer back then had the preamplifier for some time.) The only issue was the unit's microphonics--that not only included the tubes but weirdly enough the caps.
 
The jp500 is a line preamp only. There was a remote controlled line version over them, very pretty.
Never listened the 500or 800 but the 200 is a very nice unit ... erhhh 4 units.
 
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