Bottlehead Forum
General Category => General Discussion => Topic started by: mcandmar on February 09, 2014, 01:28:35 PM
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I have noticed a trend with NOS 6DN7 tubes being very noisy and needing run for hours before they settle down. What i am wondering if its just as simple as running the heater element to warm them up, or do they need current flowing through them to burn in? Basically i'm thinking of putting together a simple rig just to power up the heaters and bed them in. Has anybody tried this, or have any thoughts on the theory?
Cheers,
Mark
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There are two physical effects I can think of:
1) "Forming" the cathode - requires plate current. Too much for a post; look it up in old books if anyone is interested.
2) The "getter" - usually a silvery flash on the inside surface - scavenges gasses from the vacuum; it takes heat to do this so the pore power the tube dissipates the faster the getter can function.
It is reasonable to expect both effects to be needed after a tube has been idle for a long time.
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I've also just learnt the plates themselves heat up in operation and emit infrared radiation. I thought the heater element was the only heat source, you really do learn something new every day.
Nevermind though, if its not as simple as just feeding them heater voltage its not worth the effort trying to build a rig.
Cheers,
Mark
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Are you sure its the tubes and not the capacitors? I've found that interstage and parafeed caps need a long time to burn in. Sometimes hundreds of hours.
That said, I like to warm my system up for a while before a listening session. If I start listening from a cold startup I notice the sound getting better after the first hour or so. Admittedly that might be my ears "warming up" as well.
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Positive, this is for new tubes that have never been used before, or have sat in storage for a few decades.
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I like to warm my system up for a while before a listening session. If I start listening from a cold startup I notice the sound getting better after the first hour or so. Admittedly that might be my ears "warming up" as well.
My Dynaco MkIV amps need at least 30 min running my tuner at low volume to have full dynamics. Better an hour. As for burn-in I always have music playing.
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I like to warm my system up for a while before a listening session. If I start listening from a cold startup I notice the sound getting better after the first hour or so. Admittedly that might be my ears "warming up" as well.
My Dynaco MkIV amps need at least 30 min running my tuner at low volume to have full dynamics. Better an hour. As for burn-in I always have music playing.
+1 Yep I normally get in from work wash, change turn on the amp and it stays on all evening. If I am not listening I just put the playlist on repeat.
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. . . I like to warm my system up for a while before a listening session. . . . Admittedly that might be my ears "warming up" as well.
I know I warm up to listening. I pour 2 fingers of Bourbon 2 or 3 times a week for a listening session. By the end, even after an hour of the system playing, I am warmed up.
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Hi all.
I don't need any warm up, here in Vietnam it's 95F.
My amplifier warms up very quickly
and even needs to be cool down with a fan
as it gets burning hot.
Guy 13
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Hi all.
I don't need any warm up, here in Vietnam it's 95F.
My amplifier warms up very quickly
and even needs to be cool down with a fan
as it gets burning hot.
Guy 13
That's why there is Bia Saigon!!!
Cheers,
Geary