mhardy6647
Lunatic Member
Blue is good; the vacuum is "hard" (i.e., high).
Amp gave me a nice light show tonight
- Thread starter WopOnTour
- Start date
Tube glow has a primordial attraction for me, like a fire in my woodstove does. It's very relaxing and therapeutic, sitting in front of my TAD 60 listening to music with my wife and watching the electrons dance around in the 6550C's. 
***Do not be confused or distracted by the dancing Banana!***
***Do not be confused or distracted by the dancing Banana!***
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WopOnTour
Hoarder Extraordinaire
Totally Agree! Those fitty's look GREAT!Fran604g said:Tube glow has a primordial attraction for me, like a fire in my woodstove does. It's very relaxing and therapeutic, sitting in front of my TAD 60 listening to music with my wife and watching the electrons dance around in the 6550C's.
***Do not be confused or distracted by the dancing Banana!***
I like how the dancing blue aura is a bit hazy and fills almost the entire area between the mica discs. Very Cool
Here's another shot of the 6L6's from the back of my ol' H/K
WopOnTour
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OvenMaster
Baby, you're my winterblue
Whoa, this reminds me of an old (1950's) Ampeg guitar amp I used to have in the 80's with a 5Y3 rectifier that used to glow purple inside. I worried that it was emitting x-rays!
Tom
Tom
jaymanaa
RIP 1961-2018
I found an interesting article by Sylvania in an old tube book and thought it might interst you guys. It is entitled "Three Reasons for Blue Glow"
Many inquiries are received relative to the blue glow which is present in a number of Sylvania tubes. Most of these are based on the misunderstanding of the different types of glow that may be present in a tube. There are three types of blue haze that may appear while tubes are in operation. They are classed as: Flourescent glow; Mercury Vapor Haze; Gas.
The flourescent glow is usually of violet color, and is noticeable around the inside surface of the glass bulb. This glow is a phenomenon caused by electronic bombardment taking place inside the tube. This glow changes with the intensity of the signal and may at times become quite brilliant. Flourescent glow has absolutely no affect on the operation of a receiver. In fact, tubes with this charecteristic are particularly good as regards to gas content.
Mercury vapor haze is a blue glow which is noticeable between the plate and filament in types 82 and 83 rectifier tubes. These are the only types of Sylvania receiving tubes in which this type of haze appears. The perfect operation of types 82 and 83 is dependent upon a mercury vapor which comes from free mercury that has been placed in the bulb during the exhaust period. Therefore this type of blue haze is in no way detrimental to the operation of these tubes.
Testing for the above conditions can be best accomplished by actual operation in a receiver. It is not necessary to test for the blue glow evident in type 82 and 83, since this is charecteristic of these two tubes.
When in doubt as to the blue content of other types of tubes a sure test can be made by using a strong magnet next to the bulb. A gassy tube will not be affected in any way by the presence of the magnet, while the flourecent glow, which has no affect on the performance of the tube, will shift about as the magneteic field is shifted.
I thought it was a pretty good article. I was testing some hg vapor tubes and included some pics. The little 83 doesn't glow much, and I only had voltage on one plate. The 866 turned a beautiful chrome color while warming up, and a nice blue when voltage was applied. The last is a 2A3 out of a batch of 5 JAN RCAs NOS ones that all glow blue up around the top of the bulb. Tubes are just cool :thmbsp:
Many inquiries are received relative to the blue glow which is present in a number of Sylvania tubes. Most of these are based on the misunderstanding of the different types of glow that may be present in a tube. There are three types of blue haze that may appear while tubes are in operation. They are classed as: Flourescent glow; Mercury Vapor Haze; Gas.
The flourescent glow is usually of violet color, and is noticeable around the inside surface of the glass bulb. This glow is a phenomenon caused by electronic bombardment taking place inside the tube. This glow changes with the intensity of the signal and may at times become quite brilliant. Flourescent glow has absolutely no affect on the operation of a receiver. In fact, tubes with this charecteristic are particularly good as regards to gas content.
Mercury vapor haze is a blue glow which is noticeable between the plate and filament in types 82 and 83 rectifier tubes. These are the only types of Sylvania receiving tubes in which this type of haze appears. The perfect operation of types 82 and 83 is dependent upon a mercury vapor which comes from free mercury that has been placed in the bulb during the exhaust period. Therefore this type of blue haze is in no way detrimental to the operation of these tubes.
Testing for the above conditions can be best accomplished by actual operation in a receiver. It is not necessary to test for the blue glow evident in type 82 and 83, since this is charecteristic of these two tubes.
When in doubt as to the blue content of other types of tubes a sure test can be made by using a strong magnet next to the bulb. A gassy tube will not be affected in any way by the presence of the magnet, while the flourecent glow, which has no affect on the performance of the tube, will shift about as the magneteic field is shifted.
I thought it was a pretty good article. I was testing some hg vapor tubes and included some pics. The little 83 doesn't glow much, and I only had voltage on one plate. The 866 turned a beautiful chrome color while warming up, and a nice blue when voltage was applied. The last is a 2A3 out of a batch of 5 JAN RCAs NOS ones that all glow blue up around the top of the bulb. Tubes are just cool :thmbsp:
jt1stcav
Up and Coming Bottlehead
In my case, pink (or a purpleish cast) means life, as in my preamp's OC3 and OD3 gas regulators (NOS '58 and '67 RCAs respectfully).:yes:You have to worry if they glow pink. Pink means death (gas). Blue just means very cool looking
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smollett5
Well-Known Member
Check out this website for a full discussion, complete with photos:
http://www.jacmusic.com/html/articles/blueglow/blueglow.htm
I use NOS 7591As in my amps (one of them does use 7868s) and, when new, they have the same degree of intense blue light. Very neat.
http://www.jacmusic.com/html/articles/blueglow/blueglow.htm
I use NOS 7591As in my amps (one of them does use 7868s) and, when new, they have the same degree of intense blue light. Very neat.
My 2A3 SE home brew amp produces plenty of gas glow driving my magnepans. And a ampex console I rescued from trash pickup with 6973s has some too driving its factory internal 3-way speakers. But my 805s just get really bright on the filaments with no gas glow.
BTW: anybody have direct experience with ampex console (date stamped 14 october 1959) sporting pullout drawer housing stereo tape deck, garrard RC88 with mag cart, AM-FM mono tuner, updated 402 preamp and dual monoblock PAs with PP 6973 and triad iron? Speakers are behind sliding doors and are 3 way but impossible to get at without destroying perfect cane grilles. Tape deck only records on one channel but plays well. All other components work perfectly. Thank you. --TH
BTW: anybody have direct experience with ampex console (date stamped 14 october 1959) sporting pullout drawer housing stereo tape deck, garrard RC88 with mag cart, AM-FM mono tuner, updated 402 preamp and dual monoblock PAs with PP 6973 and triad iron? Speakers are behind sliding doors and are 3 way but impossible to get at without destroying perfect cane grilles. Tape deck only records on one channel but plays well. All other components work perfectly. Thank you. --TH
So, I'm _not_ crazy, at least in this respect: I had a distinct memory of seeing the power tubes in my Fender Bassman amp (some 30 years ago now) glow and pulse according to what I was doing on the guitar (I'd sneak around back sometimes just to peak). Mentioned it to a couple of audiophiles I know and they said they doubted it. Thanks for those photos!
jaymanaa
RIP 1961-2018
I heard once that Jimi Hendrix wrote the song "Purple Haze" after being inspired by glowing tubes. I think he was talking about something else though.
WopOnTour
Hoarder Extraordinaire
LOL I would think so...I heard once that Jimi Hendrix wrote the song "Purple Haze" after being inspired by glowing tubes. I think he was talking about something else though.
Hey THANKS to those that posted links to excellent explainations for this phenomena. It's good to know it's not a "problem" with the tubes or anything (quite the opposite it appears actually)
It's funny because now I almost always turn off the lights when listening to this amp.
WopOnTour
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jcmusic
Well-Known Member
I heard once that Jimi Hendrix wrote the song "Purple Haze" after being inspired by glowing tubes. I think he was talking about something else though.
I am pretty sure he was talking about something else.
Jay