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Old 21st October 2012, 08:34 PM   #11
DF96 is offline DF96  England
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Four categories could be used:
A: new unused (except perhaps for a brief spell in a tester).
B: used, but tests OK
C: possibly useable, but tests weak so probably will fail soon
D: not working

A and B cannot be distinguished by any electrical test so you just have to trust the history supplied by the vendor. It is not possible to determine how long a B valve has to go before it will become a C. D valves are often offered for sale on ebay as 'untested'; just look for the white getter.
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Old 21st October 2012, 08:44 PM   #12
kevinkr is offline kevinkr  United States
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There is unlikely to be any agreement on grading so my best advice is to look carefully at seller feedback, and what the terms are for return/refund if you are not completely satisfied.

I have had just one instance of a bad transaction buying tubes on eBay out of the hundreds I have purchased there, luck and care I guess, once vetted I will usually go back to the same sellers for more of the same.

My best overall experiences have generally been with sellers from the U.S., U.K., Germany, Russia, and the Ukraine. No bad deals with sellers in any of these countries.
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
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Old 21st October 2012, 09:35 PM   #13
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True it is that when you buy on say Ebay, you run a risk that a tube claimed as tested isn't tested or the seller did not do an accurate test.

On the other hand, some sellers (like me) would get accurate readings. I'd like to give out those readings and let a buyer know just what he is getting. And I thought, would it not be nice if I could say I had a tube in a recognised and classified electrical condition. Similar to what booksellers do.

But, perhaps a classification is not needed. Just post the test results and let buyers figure what they are getting. Perhaps most will know what they are getting if you simply state ionic current, mutual conductance and insulation readings. It then really is up to the buyer to know what the test figures mean. Although perhaps the seller could also point out what the figures mean to a buyer.

Last edited by richard8976; 21st October 2012 at 09:40 PM.
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Old 21st October 2012, 10:00 PM   #14
Join Date: Oct 2012
It is good practice to do that with the buyer but some sellers don't even respond when you send them email about the item etc so it kinda is like shooting in the dark so to speak but you can get some good deals on ebay with tubes that are perfectly fine and will last for years
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Old 21st October 2012, 10:03 PM   #15
Join Date: Oct 2012
I'm never buying anything current production ever again and I mean NEVER lol I use to think Nos was all overrated and hyped way too much boy I was wrong xD
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Old 21st October 2012, 10:15 PM   #16
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I've just got two vintage GEC KT88's. I think one needs "baking" to activate the getter. Passing about 4 uA grid current. If I can get the ionic current down, they will no doubt end up on Ebay! :c)

I intend to get accurate test figures and provide that information - whatever they are.
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Old 21st October 2012, 10:17 PM   #17
Join Date: Oct 2012
That's what I love about all this stuff you learn so much just from taking chances/blowing things up destroying whatever or maybe it was bad luck so you try not to do it ever again yet there is always that possibility same **** will happen again lol or maybe I was just young and dumb at one time xD
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Old 21st October 2012, 10:17 PM   #18
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I always buy from reputable dealers.
I wouldnt buy new or second hand off ebay.

Second hand tubes can be a minefield, they can work one day and stop the next if you are unlucky or been handied junk from a dodgy seller.
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Old 21st October 2012, 10:29 PM   #19
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dude those GEC kt88s really kick *** lol
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Old 21st October 2012, 10:38 PM   #20
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My budy had the jet city 50watter and I had some of the cheap rubys and the GEC Kt88s at the time now Don't ever do this for extended periods of time the transformers are not up to kt88 spec really but we popped em in for the hell of it xD and you know what they both really sounded amazing but the GEC was in a league of its own stacked 2 overdrive pedals and attenuate running into a stereo setup total 80s meltdown lol
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