tubes age 165
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Date: Sun, 29 Jan 2006 17:11:55 -0000
Subject: RE: [R-390] CV133 vs 6C4
5814A = 12AU7 = ECC82 = CV491 5814WA = M8136 = CV4003 = 6189
|>Someone once tried to convince me that the euro EC-tube number system
|>(e.g. ECC82) made a lot more sense than our system (filament voltage +
|>letter(s) + number of terminals) but they didn't convince me. Maybe
|>there is a rhyme and reason to the CV numbers but I don't see it.
E = 6.3v heater C = Triode C = second triode 82 Base type (B9A)
There is no logic to CV numbers, and many exceptions to any percieved "rules",
but the CV sequence started during WW2 to try and produce a common
numbering system for devices used by the Navy, Army, and the RAF, plus other
government agencies such as the General Post Office (GPO), all of which used
their own numbering systems in addition to those used by US and
European manufacturers. CV numbers were also allotted to devices with
tighter specifications that normal, ruggedised versions and variations for
special purposes. Later, the system expanded to include semiconductors.
http://www.tubecollector.org/
will tell you everything you need to know about the CV numbering system and a
whole lot more.
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Date: Thu, 16 Feb 2006 14:51:33 -0500
Subject: Re: [R-390] "Fake" 12AX7 tubes on e*pay
I have many "Tesla"/"JJ" (E European) 12AU7A's (actually labeled ECC82, I
always thought ECC82 equals 12AU7A's but seeing the subject line maybe you
don't think so) and several have already failed with cathode-to-heater shorts in
the past couple years. Maybe 30% failure rate. That is not "excellent" in my
book, to me it indicates less-than-stellar manufacturing. It's pretty obvious (from
the massive amounts of hum) when the short happens. Maybe I just got a bad
batch. And my batch was only 20 tubes. So discount my experience if you wish.
I have bought batches of surplus JAN tubes (typically 60's/70's/early 80's) as
well and have not experienced this problem with them.
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