2359glenn | studio
Mar 8, 2021 at 2:20 PM Post #38,372 of 39,451

L0rdGwyn

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:thinking: :rolling_eyes::sweat::worried::astonished::disappointed:
Could you please repeat that in Greek so I have a chance to understand?

Thank you for your effort. :wink:

What about them curves?

Well, they look okay, not sure where they bias in the GOTL, but would want to operate them at a highish current to get the load line out of the large knee of the curves!
 
Mar 8, 2021 at 2:39 PM Post #38,374 of 39,451

L0rdGwyn

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FYI, most people are using these as output tubes, preferably 3 per side.

Sounds like people like the results too. Better than 6BX7 would you say, @gibosi ? Well I have tried to chime in with technical explanations in Glenn's absence as best as I am able, so happy to help when it comes to interpreting datasheets and whatnot.
 
Mar 8, 2021 at 4:14 PM Post #38,375 of 39,451

gibosi

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Sounds like people like the results too. Better than 6BX7 would you say, @gibosi ? Well I have tried to chime in with technical explanations in Glenn's absence as best as I am able, so happy to help when it comes to interpreting datasheets and whatnot.

Your efforts are much appreciated. :)

And I don't know as I would say the 6N12S is "better." To my mind it sounds like a Melz or Telefunken 6BX7, if they existed. And even so, I'm sure that some would still prefer RCA or Sylvania or what have you. :)
 
Mar 8, 2021 at 7:06 PM Post #38,376 of 39,451

mordy

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Your efforts are much appreciated. :)

And I don't know as I would say the 6N12S is "better." To my mind it sounds like a Melz or Telefunken 6BX7, if they existed. And even so, I'm sure that some would still prefer RCA or Sylvania or what have you. :)
I found that the Melz 6N12S has an incisive (biting) quality with great clarity and instrument separation and with the right driver tube(s) they can sound excellent. -Did not experience the same with the 6BL/X7 tubes.
 
Mar 8, 2021 at 8:16 PM Post #38,377 of 39,451

gibosi

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I found that the Melz 6N12S has an incisive (biting) quality with great clarity and instrument separation and with the right driver tube(s) they can sound excellent. -Did not experience the same with the 6BL/X7 tubes.

True. But as I tried to point out, if Melz had made 6BL/X7 tubes they would likely sound very similar to the 6N12S. The "Melz factory sound". :)
 
Mar 8, 2021 at 10:36 PM Post #38,378 of 39,451

MIKELAP

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Last night, after using the Z63 tubes for around 12 hours, there was a pop and one of the tubes started to glow significantly brighter than before. I shut off the amp right away.
Does this very much increased brightness indicate that the tube is failing?
Is it dangerous to continue using it?
That happen to me 4-5 years ago i had a 274B Sophia Princess that became very bright but was still working i to shut it off right away .Never check on it after
 
Mar 8, 2021 at 11:08 PM Post #38,379 of 39,451

mordy

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That happen to me 4-5 years ago i had a 274B Sophia Princess that became very bright but was still working i to shut it off right away .Never check on it after
I immediately shut off the amp with that Z63 tube that suddenly made a popping sound and then turned very bright. The next time I turned on the amp it did not turn on - a fiery death...
 
Mar 9, 2021 at 2:36 AM Post #38,380 of 39,451

Xcalibur255

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That happen to me 4-5 years ago i had a 274B Sophia Princess that became very bright but was still working i to shut it off right away .Never check on it after

Was it just the filament that became brighter than normal, or did it seem like there was a sort of hazy glow throughout the tube? The former can be bad but can also be normal for certain types of tubes. The latter is always bad and usually means your tube has lost its vacuum integrity and is now gassy. Tubes are only useful as display pieces once they become gassy.

edit: I suppose I should point out that technically mercury vapor tubes exist and do exhibit a hazy blue glow as normal operation before somebody else does, but that's clearly not what we're talking about here. :wink:
 
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Mar 9, 2021 at 4:27 PM Post #38,381 of 39,451

mordy

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I am testing an ST type tube with an anode cap in the 6J7 family. It sounds very good with one caveat - of the three different makes I have, all of them hum to a greater or lesser degree. It is a low level hum (similar to 50hz hum) that does not vary with the amp volume; other tubes in the same family are quiet.
By wrapping the tubes in aluminum foil AND grounding the foil to the amp chassis I can reduce the hum - some of the sets are still objectionably humming, and some less so, but the hum is there even though some of tubes are listenable.
I am sure that the hum comes from the tubes themselves. Does anybody have an idea of how to eliminate it?
 
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Mar 9, 2021 at 4:57 PM Post #38,382 of 39,451

bcowen

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I am testing an ST type tube with an anode cap in the 6J7 family. It sounds very good with one caveat - of the three different makes I have, all of them hum to a greater or lesser degree. It is a low level hum (similar to 50hz hum) that does not vary with the amp volume; other tubes in the same family are quiet.
By wrapping the tubes in aluminum foil AND grounding the foil to the amp chassis I can reduce the hum - some of the sets are still objectionably humming, and some less so, but the hum is there even though some of tubes are listenable.
I am sure that the hum comes from the tubes themselves. Does anybody have an idea of how to eliminate it?

Is the wire going to the anode cap shielded (with one end of the shield tied to ground)? That's helped in the past for me.
 
Mar 9, 2021 at 6:10 PM Post #38,383 of 39,451

tubebuyer2020

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By wrapping the tubes in aluminum foil AND grounding the foil to the amp chassis I can reduce the hum - some of the sets are still objectionably humming, and some less so, but the hum is there even though some of tubes are listenable.

Here is a controversial opinion: that is completely normal, leaving tubes exposed is a modern thing.

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Mar 10, 2021 at 2:29 PM Post #38,385 of 39,451

Akiravelvet

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Has anybody tried out a cossor fat bottle cv378? Any comparisons Between that and the skinny bottle version? Is the fat bottle worth the extra price?
 

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