What you see here are NOS tubes, that
I purchased when I was their main distributer.
Attention: All
tubes ending on "M" are mesh plate tubes
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With AVVT tubes you need to know where you
buy. They really made some good stuff.
I have kept track of the reliability of all tubes
I sold, be registering the series numbers. From this I can conclude,
that the AVVT tubes from 1999-2001 were generally of very good quality.
For me, these are the only years from wich you can buy them without
risk. Specially in 2000 and 2001, tubes were made of almost
near-perfect quality with respect to reliability and lifetime.
Tubes from before 1999 can be good, as long as they are not private
branded. So there must be only "AVVT" on those, and you're
ok.
Tubes from the older "VAIC-VALVE" brand (1997
and older) are generally good quality.
Tubes from 2002 or later, and so called "REF"
series I do not sell or buy.
A factory test report is with each mathed pair.
** Report **
The
history of AVVT 2A3 tubes, and 2A3-MESH tubes
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TUBE TEST REPORT
Click here
for a test report on the AV300B by Enjoythemusic.com
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TWEAK REPORT
Click here
for a tweak report on a pair of Bottlehead parafeed 2A3 amps by Enjoythemusic.com
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Note about storage of AVVT tubes:
It seems the maximum storage time of those tubes is 5...7
years. We do not really know yet, but this is what is seems like.
Does that mean older tubes are bad? Probably not!
But... you need to take care of the following:
If the tubes must be stored longer, they need to be run at full
power for 20 minutes, and two hours at normal power afterwards.
Then they can be safely stored again for another period. In case
a tube was stored longer than 8 years, you may find the transconductance
is 30% reduced or more. So you must verify the original old DC test
data, if they are still with the tubes. In case you observe 20...50%
lower DC current, you will also have lower transconductance. When
this has happened, do not use the tube, or your attemps may damage
it permanently. Such a tube can be brought back into
good condition, when you have the equipment for it. You can send
it, and we can do that for you. So far, this seemed only
necesairy with the Vaic-Valve 52B's from around 1996, but it will
probably also be necesairy with other tubes when the years pass by,
and older NOS tubes are found.
Remember, this is only the case when the tubes were stored from
the beginning, and never used ever since. This is nothing unuseual,
and it is almost normal with NOS tubes, like 6SN7. I bought
a NOS pair WE-205D, that was only testing "fair". After re-activation,
it was exactly like on the datasheet again. When the tubes are used
every now and then, they will just stay in good condition.
So here comes my old saying again, that good "used" tubes can be
better condition than random NOS tubes that were stored ever since.