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primer on buying vintage tubes?

Dear all-

I recently started to tiptoe into tube rolling--replacing the 6922 stock tubes in my headphone amp etc.

I am curious as to why vintage tubes are often preferred to the new ones? Why would older tubes sound better?

And even more pressing, I'm curious about best practices for buying vintage tubes. I recently came across a pair on ebay that were not labeled NOS but the seller did say the had been measured on a tube tester and had 100% emission. If this a safe bet? Is it better to buy NOS? Is it better yet to deal with a vendor like Upscale Audio?

Thanks for any insights! Margot
mcanaday
elevick
2,439 posts
 
The good thing about 6922's is that they have really long lives in the scheme of things. Usually 5000 to 10,000 hours. We all have our preferences but most prefer NOS. I agree with the comments about ebay.
Buying from here or audiogon is usually safe. Other good dealer such as upscale are tubesandmore.com and thetubestore.com. Sometimes echohifi has good buys. Some sites are fun to peruse but are way too pricey such as tubeworld.com.
mcanaday OP
148 posts
 
Thanks, guys! And how do you know if you got a bad tube? Is it obvious?

Cheers, Margot
sfar's avatar
Ag insider logo xs@2x
sfar
1,352 posts
 
-
Another excellent source of tubes, both vintage and new production, and great advice about any of them, is
JIm McShane.
All his tubes are thoroughly tested and he stands behind them.
lowrider57's avatar
lowrider57
3,018 posts
 
Margot, the most common way a tube goes bad is to die a natural death. It happens over time, and you'll notice that the highs in your system aren't as bright or the music isn't as dynamic as it used to be.
Very often, the tell-tale signs of a tube gone bad are; the channel is dead or the sound is cutting in and out. All of a sudden there might be hissing or crackling coming thru one of the channels.

If a tube has become microphonic, it means the tube is unstable and vibrating; you may hear unusual overtones in the music.
mcanaday OP
148 posts
 
Thanks Lowrider and everyone. This is all extremely helpful! I am excited to get started.... Cheers, Margot
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