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How is this posible...

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Posted on August 17, 2024 at 13:27:36
ABliss
Audiophile

Posts: 1539
Joined: March 16, 2001
Contributor
  Since: August 3, 2002






I went back to using the stock 6NIP tubes in my Musical Paradise preamp a few day ago.
Last night, with the system totally off for hours, I was watching TV, and I heard the subwoofer turn on with a sudden thump, like when the preamp powers on but louder. Even scared the dogs.
I looked and the sub was on but everything else was off, so I didn't know what to think caused it.

Well today I powered up as usual, preamp first, it came on and the sub turned on.
But when I looked at the tubes, one had no light, it's as hot as the others but no light, and both channels are still working and sounds fine.
Is that possible, shouldn't one channel be dead ?
Did this tube surge the sub last night, or did the sub surge it? How could either one do this with them being powered off.
Should I rush to replace the tube?

Any thoughts welcome.

 

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RE: How is this posible..., posted on August 18, 2024 at 11:43:54
Tre'
Industry Professional

Posts: 17554
Location: So. Cal.
Joined: February 9, 2002
 I would love to see a schematic so I can understand why the preamp has normal output with one tube not working.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: How is this posible..., posted on August 18, 2024 at 11:54:01
ABliss
Audiophile

Posts: 1539
Joined: March 16, 2001
Contributor
  Since: August 3, 2002
 I wish I had one, but it's Chinese so availability is doubtful.

 

RE: How is this posible..., posted on August 18, 2024 at 18:04:47
mraudio
Audiophile

Posts: 476
Location: Northern Colorado
Joined: November 4, 2006
 Send Garry an email. He's pretty cool.

guangyaoca@gmail.com

 

Maybe that third one is just for show?, posted on August 18, 2024 at 18:09:09
Sondek
Audiophile

Posts: 9930
Location: Fort Worth
Joined: May 17, 2000
Contributor
  Since: April 5, 2002
 Kidding, but it is hard to understand how it is possible.

 

I did today, waiting on a reply.....nt., posted on August 18, 2024 at 20:07:52
ABliss
Audiophile

Posts: 1539
Joined: March 16, 2001
Contributor
  Since: August 3, 2002
 Nt.

 

RE: Maybe that third one is just for show?, posted on August 18, 2024 at 20:17:55
ABliss
Audiophile

Posts: 1539
Joined: March 16, 2001
Contributor
  Since: August 3, 2002
 I am thinking that the tube is still working, it's just not glowing.
It's still sounding good, not even a bit of distortion. I have a new set on the way, as soon as they come I will swap it out, and hope it's just the tube issue.

 

RE: Maybe that third one is just for show?, posted on August 19, 2024 at 18:15:21
Tre'
Industry Professional

Posts: 17554
Location: So. Cal.
Joined: February 9, 2002
 A tube can not work if the cathode is not hot. The heater in the middle of the cathode has to glow if it is hot. That tube's cathode is not being heated. That tube can not be working.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: Maybe that third one is just for show?, posted on August 19, 2024 at 18:34:27
Jim McShane
Dealer

Posts: 5919
Location: Chicago
Joined: January 13, 2003
 But the glow does not have to be visible! If the heater is covered by the plate and or cathode structure then it can seem to be not working even though it is working and the cathode is properly heated. The most common example of a tube that does that is the 12AX7LPS Sovtek. I get inquiries all the time about that tube not glowing - and I always ask if it is hot.

His is hot, so I am virutally certain the tube is fine, but the heater is not visible.

 

RE: Maybe that third one is just for show?, posted on August 19, 2024 at 19:17:58
Tre'
Industry Professional

Posts: 17554
Location: So. Cal.
Joined: February 9, 2002









"If the heater is covered by the plate and or cathode structure" but it's not. Look at the other 2 tubes in the picture. You can see the heater glow from top to bottom.
That tube is build like 6080 with a plate on either side of the heater/cathode/grid structure that is totally exposed at the sides and, like a 6080, you can clearly see the heater glow.

A 6080




Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

Have you checked all three inputs?, posted on August 20, 2024 at 04:18:36
Triode_Kingdom
Audiophile

Posts: 10181
Location: Central Texas
Joined: September 24, 2006
 Maybe one is dead now.

 

RE: Maybe that third one is just for show?, posted on August 20, 2024 at 09:50:41
Jim McShane
Dealer

Posts: 5919
Location: Chicago
Joined: January 13, 2003
 "Look at the other 2 tubes in the picture. You can see the heater glow from top to bottom."

The same thing happens in the LPS Sovteks I mentioned. Some hide the heater completely and some do not. There is some construction variance/tolerance between tubes that hides some heaters but does not hide others.

 

RE: Maybe that third one is just for show?, posted on August 20, 2024 at 09:53:40
Jim McShane
Dealer

Posts: 5919
Location: Chicago
Joined: January 13, 2003
 Why don't you just swap the suspect tube with each of the two other tubes that DO have visible glow and see if everything continues to work normally?

If it all continues to work then you wil KNOW that tube is fine.

 

RE: Maybe that third one is just for show?, posted on August 20, 2024 at 11:49:08
Sondek
Audiophile

Posts: 9930
Location: Fort Worth
Joined: May 17, 2000
Contributor
  Since: April 5, 2002
 Although I don't think the OP told us this, but my inference was that prior to the subwoofer bump, all three tubes looked the same.

If that inference was/is incorrect, then yours is the only other plausible explanation.

 

RE: Maybe that third one is just for show?, posted on August 20, 2024 at 17:47:21
ABliss
Audiophile

Posts: 1539
Joined: March 16, 2001
Contributor
  Since: August 3, 2002
 Yes, prior to the subwoofer loud thump they all glowed the same, very bright compared to the 6922s I had in.
The 6nips are very new with less than fifty hours on them. It has no light, but feels hot like the others. So it must be working but something caused the glow to turn off, and I feel ninty percent it had something to do with the sub.

I emailed the dealer, he thinks the sub could have turned on by some radio interference or surge, and maybe it backfeed to the tube. He thinks the tube is still good if it plays and is hot.
I asked about a schematic, he says they don't give it out.

I have a new set of Russian 6nips coming tomorrow, so I will remove these Chinese ones and see if my Eico can test them.

 

No I haven't, but I will...nt., posted on August 20, 2024 at 17:49:39
ABliss
Audiophile

Posts: 1539
Joined: March 16, 2001
Contributor
  Since: August 3, 2002
 Nt.

 

RE: Maybe that third one is just for show?, posted on August 21, 2024 at 11:20:37
Jim McShane
Dealer

Posts: 5919
Location: Chicago
Joined: January 13, 2003
 If you know for certain the tube used to have a visible orange glow and it is now not visible then that's a different story. What I posted before is all true, but it doesn't apply in this case since the tube changed.

Just swap the "no glow" tube with one of the other 6n1p tubes that does glow and see how it looks in a different socket. That's the easiest way to narrow down what the issue is in this case.

Finally - the Russian 6n1p tubes are a better choice than the Chinese ones IMHO. I've sold about 80 of the 100 Russian ones I had and have yet to have a single issue with any of them.

 

RE: Maybe that third one is just for show?, posted on August 22, 2024 at 14:06:26
ABliss
Audiophile

Posts: 1539
Joined: March 16, 2001
Contributor
  Since: August 3, 2002
 Thanks for the follow up. I swapped them around and that one tube is totally dead now. I guess it still was hanging on when it felt hot and was still playing. It doesn't even feel warm anymore.

I put in some Russian 6nip I just got and all is well.

 

Good deal. nt, posted on August 22, 2024 at 19:03:54
Tre'
Industry Professional

Posts: 17554
Location: So. Cal.
Joined: February 9, 2002
 .
Have Fun and Enjoy the Music
"Still Working the Problem"

 

Couldn't pay me to own one of their products, posted on August 24, 2024 at 06:25:10
Triode_Kingdom
Audiophile

Posts: 10181
Location: Central Texas
Joined: September 24, 2006
 "I asked about a schematic, he says they don't give it out."

Bastards, one more reason not to buy Chinese crap. Who's the dealer?


 

RE: Maybe that third one is just for show?, posted on August 25, 2024 at 11:46:03
Best audiotransformers
Industry Professional

Posts: 94
Joined: December 4, 2023
 tre,

It's about 6NIP tubes, not the tubes you mentioned.

 

RE: Couldn't pay me to own one of their products, posted on August 25, 2024 at 11:51:45
Best audiotransformers
Industry Professional

Posts: 94
Joined: December 4, 2023
 Crap is everywhere, also in the USA (a lot actually)
My Apple computer is made in China and i love it.

 

I was talking about the 6n1p. There is no such thing as a 6NIP, posted on August 26, 2024 at 13:24:49
Tre'
Industry Professional

Posts: 17554
Location: So. Cal.
Joined: February 9, 2002
 Here's the results from a google search for 6NIP.



Here's Musical Paradise page.



Furthermore, I only mentioned the 6080 because it is built the same way (with the cathode showing, top to bottom) and I thought Jim might be familiar with them.

Tre'


Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: Maybe that third one is just for show?, posted on August 26, 2024 at 13:36:46
Tre'
Industry Professional

Posts: 17554
Location: So. Cal.
Joined: February 9, 2002
 "If the heater is covered by the plate and or cathode structure then it can seem to be not working even though it is working"
It is not just the heater that glows. In a normal indirectly heated tube the heater gets the cathode so hot that the cathode also glows.You will not see this if the cathode is covered by the plate but in the 6n1p (and the 6080) the cathode is not covered by the plate. The tube below has holes in the plate and you can see the cathode glowing.




Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

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