Tube Break-In and NOS Tesla 6DJ8s

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Bernard

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After several years of having the original tubes in my ARC SP9 I decided it was time to change them, so I bought some Valvo NOS tubes, and the improvement was immediately noticeable after I allowed the tubes to warm up for about an hour.

Then I came across some Gold Aero 7308s and tried those instead. As before, I noticed an immediate improvement over even the Valvos.

I recently bought some Tesla NOS tubes on Audiogon, and on inserting them into the preamp and letting them warm up they sounded really wooly, and did not clear up after playing for about an hour.

So I was wondering if different tubes take different amounts of time to break-in. Any comments about break-in or Teslas??
 
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For my ARC I found about 100 hours on tubes before I could make a final determination on their sound - mine uses 12AX7's
 
We're talking Tesla Vrsovice, not JJ, right Bernard?

I had some NOS Tesla Vrsovice ECC803S and some NOS Telefunken ECC803S at the same time. The later are supposed to be "best ECC83" in the world. And I think they probably are - they sell for megabucks. However, the Tesla version, which is supposed to have used the same tooling equipment I believe, was every bit as good. Their KT88 was the best I tried too - now E.A.T. I sold the Teles for more than I paid for them - quite a bit more, in fact - easily covered the Teslas which were around £50 for the pair.

I rate them (Tesla V.) really highly for sound, though KT88 reliability leaves a lot to be desired. Maybe the 6DJ8 is dodgy, though:)

BTW: tube break-in? I have never noticed that tubes need it. Bizarre. But that doesn't mean that I am right - I just haven't noticed a difference between new and, say, 100 hours of usage.
 
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Just wondered if anyone has had any tubes cryo treated? If so, what's your verdict?

Sure Bernard won't mind this being discussed here too?
 
We're talking Tesla Vrsovice, not JJ, right Bernard?
The tubes I have are just marked "Tesla"; there are no "JJ" markings anywhere. How do you distinguish between the two?

And no, I have no objection to discussions about cryo treating tubes in this thread.
 
That's a Tesla Vrsovice, then. Silk screen is probably white or yellow, I expect. It may have gold pins... just seen some that have on ebay.
 
I ordered several cryoed 6H30's and did not find them different from regular flavor. That is not to say they don't make a difference, only my observation in my ARC PH7. Probable cause for no sound difference is that they are used in the power supply in this application.
 
That's a Tesla Vrsovice, then. Silk screen is probably white or yellow, I expect. It may have gold pins... just seen some that have on ebay.
The silkscreen is white, except for two letters ("UD" in CAPS) which are yellow. The pins are gold.
 
So I was wondering if different tubes take different amounts of time to break-in. Any comments about break-in or Teslas??

You trying to 'bait' me Bernard ??

On the serious side I'd say the psychoacoustic side of my brain says 40 hrs or so, but truthfully I probably wouldn't know the difference between a new and one with 40-100 hrs on it !
 
On the serious side I'd say the psychoacoustic side of my brain says 40 hrs or so, but truthfully I probably wouldn't know the difference between a new and one with 40-100 hrs on it !
If there is a tube you really like, next time you get a new pair, buy two new pair. Since you like the tube already, getting another pair is not a big deal.

Run the one pair for 25, 50, 75, 100 hours and then put the new ones in to compare. This is the best and only way to hear any changes - otherwise we "think" we hear changes or not.
 
You trying to 'bait' me Bernard ??

On the serious side I'd say the psychoacoustic side of my brain says 40 hrs or so, but truthfully I probably wouldn't know the difference between a new and one with 40-100 hrs on it !
No baiting here, Dave :) I'll leave the preamp on for a few days before passing judgement.
 
Your pre will probably sound better for that anyway... so turn it off again, I guess, and let it cool before you try again...
 

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