Technician put these values on my preamp tubes - What do they represent?

I would also expect they will tell you what they use if you ask. Its not exactly a "dude in a garage under a cloak of great mysticism" sort of operation.
My tube test guy works this way. But he does bring his tester out for special events.
 
This is all information I like learning about. The technician was not satisfied with what he found when testing my preamp tubes, and they were not very expensive to let him replace. The actual repair they made, by the way, was replacing a FET. Knowing that level of information about a particular amp that is now old enough to vote is why I was happy I sent it to them.
 
Audio Research wrote: The numbers are the tube grades. Whenever you need to replace tubes individually, its best to provide us with the grade number when ordering, so we can select new tubes in the same grade range.
 
Audio Research wrote: The numbers are the tube grades. Whenever you need to replace tubes individually, its best to provide us with the grade number when ordering, so we can select new tubes in the same grade range.
Tube grades are usually 1 thru 10. These tubes came directly from Audio Research? I find it odd that an elite audio operation that sell amps that cost tens of thousands of dollars would have hand written numbers on torn off pieces of what looks like masking tape for grading their tubes.
 
Tube grades are usually 1 thru 10. These tubes came directly from Audio Research? I find it odd that an elite audio operation that sell amps that cost tens of thousands of dollars would have hand written numbers on torn off pieces of what looks like masking tape for grading their tubes.
These are the tubes I had in the amp before I sent it in for repair. I bought these from an independent audio store. Audio Research received the tubes from me, made the marks on them, and returned them.
 
The numbers maybe don't tell you all the story nor did the explanation by ARC about the numbers but you can see that the numbers aren't the same and for an amp (pre/power/phono) to leave their shop it needs to be in its best operational state and that is with a fully matched set of tubes through the unit. This is what was installed for the slight upcharge you paid. More than the cost of the tubes they installed but they did spend a bit of time and equipment testing them and throwing out or returning ones that did not meet their standards. This work isn't done for free and you now have a set of tubes you can use as well as a set of tubes in the unit that make it Right according to the manufacturer. Since these are your tubes, I understand why they got a chunk of paper attached to them. They probably group matching tubes without putting a sticky on them.
 
These are the tubes I had in the amp before I sent it in for repair. I bought these from an independent audio store. Audio Research received the tubes from me, made the marks on them, and returned them.
Ok, I did not quite understand the situation. Well, at the least, you know your tubes are all in working condition. If you have your own tester, you can retest your tubes and the ones that were put in by AR and see what the differences are. Call me a doubting Thomas but i always like to know what my own tubes sound like compared to the factory ones.
 
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