At this website we show since 1998
ALEŠA VAIC VACUUM TECHNOLOGY
(Now NOS tubes)
I added this text in 2016 and 2017, after letting this website intentional fully unchanged since 2001, so far.
AUDIO NOTE BRANDED, AVVT MADE TUBES
Before 1998, Audio Note was the sole distributer of AVVT tubes, and these were Audio Note branded, with a large golden "AN" logo on the tubes. This cooperation was ended on the initiative of Audio Note. In case you want to know about reliability of such tubes, before purchasing them, I recommend you to contact Audio Note about this directly.
FAILURE STATISTICS OF AVVT TUBES
However it is necessary now, since some crooks are now trying to sell factory rejects from around the year 2000, as so called "NOS tubes". I have first seen this, beginning 2016, when several people asked me to verify series numbers of tubes that were offered on EBAY, or other internet flea markets.
Unfortunately, I learned now (in 2016) these tubes were not destroyed at all. I find this extremely disturbing, as you can understand.
I see those tube go sometimes for 1600...1800 US$ a pair, and it hurts to see these are series numbers, I have send officially back for destruction, in the years 2000...2001. They are worth only the value for defective tubes, as that is what they are. Though it's so long ago, I still have all my old database, showing what series numbers where rejected, with the data, failure reason, and what was done with the tubes afterwards. Such as replace to the buyer, or destruct or repair, or if we left the broken tubes with the buyer or not. All of it, in 100% detail. So this is what I know.
What I do not know (yet) is who is selling them, but I may find out. Please LET ME KNOW when you have details about the person.
I find this situation extremely disturbing.
Sometimes, Ebay bidders know me, or know to find this website, and ask me if the AVVT Series numbers are ok. This is a bit boring for me of course, to tell many people if the series numbers are good or bad, since I am not related to AVVT problems any more ever since 2001.
However, now with this new situation, I decided to place the failure statistics online. So you can judge it for yourself.
Please note, at that time, a small percentage of all series numbers was not captured by me. So a reverse conclusion is not always possible. Though it will be most if the time, as most REJECTED numbers are in this list indeed.
For sure, list gives a good impression of what where good periods, and what not. So if the series number is for instance like 25xx, you will recognize, there were many bad ones in that series. Adjacent is the 26xx series, and that was a much better series. Not perfect but a lot better. So a 25xx tube is worth much less than a 26xx tube, so important is, if the adjacent numbers are good, or bad.
Also you can see from this list, AVVT quality problems were completely solved with series numbers higher than 6100. From there, the defect rate is almost zero. I would say any series number above 6100 are amongst the best tubes you can buy. Feel confident to pay any NOS collectors price you think is normal. As you will see, that's unfortunately not what they are selling on Ebay. Note, 32B is good at series number above 5300 already.
So to say it again, some crook is now bringing the old factory rejects on the market, and the bad guy may not even be the final seller. Though of course the seller can help us to shed some light on it, as he knows at least where he got them from. Please let me know, if you find out names or sources. The internet has a memory, and it is a powerful memory.
These tubes series numbers are marked in my list as: "Returned for destruction". The problem with those tubes is, they are initially strong, but they will last a couple of hundred hours only, instead of 5000+ hours which you can expect from a good AVVT series number. You can definitely not go by test values that you get from a tube tester. So they will test good, but latest after burn in, problems will begin, such as hum, low output, distortion, and other signs of emission loss. So the problem is not vacuum loss, but emission loss. Actually I see these are sold including certificates, with signature and stamps, but this is only a sheet of paper. At least it is not possible to change the series numbers inside the glass bulb.
Again, when you know who is behind this, please LET ME KNOW. I have now list I did not want to have, but it is a list of persons who were fooled with such factory rejects. So perhaps, I can give those buyers someone to talk to.
This his list is an extract. For myself, I have more complete version, with tube test data, initial buyer, shipment country, etc.