Help! Is my Cary broke??

[Chris M]

I am the new owner of the Cary SLI-80 intergrated amp. I've had it for around 3 weeks without any problems until tonight. While playing a CD I heard a tick or pop in the left channel. I turned around a noticed that one of the Russian 6550's was glowing bright orange. I immediately turned it off and let it cool down. I checked everything and it looked OK so I turned it back on after awhile. Only the right channel produced any sound. All of the tubes came on per usual but the 2 6550's on the left side/channel did not have the blueish glow like the ones on the right side do. I checked the fuses and they looked fine. The Cary owner's manual said that the unit is biased at the factory so I've yet to bias it myself and it has worked fine for 3 weeks. What should I do? Does it sound like I blew a tube or is it something more serious?? Any help would appreciated as I just spent 3K on this thing and would like to have music for the 4th!!

Thanks in advance!

Chris


P.S. Why do my Russian 6550's have a blue glow to them??

[Steve Hoffman]

Chris,

Others here can help you I'm sure, but try this to see if it is a tube problem FIRST.

Take an ink marker and mark each tube with a number (so you'll know where to put them back). Won't hurt 'em.

Now, switch the left channel 6550s with the right. Don't worry about bias for now. This won't hurt them either.

If it's a tube, the left channel should now work and the right be dead, correct?

If it's still the left, it's something else....But find this out first..

Don't panic. Simple circuits.

[Chris M]

OK, I numbered and swapped the 2 left side 6550's w/ the 2 right side 6550's and the left channel is *still* dead. So this should mean that the tubes are OK and something is wrong w/ the left channel of my Cary, right? FWIW, the 6550's on the right side have that blue glow while the ones on the left glow but not blue (just orange). Steve, thanks for your help. It's a little intimidating dealing w/ expensive tube equipment the first time around:(

Chris

P.S. Will I damage my amp by playing the right channel only?

[Khorn]

Originally posted by Chris M
OK, I numbered and swapped the 2 left side 6550's w/ the 2 right side 6550's and the left channel is *still* dead. So this should mean that the tubes are OK and something is wrong w/ the left channel of my Cary, right? FWIW, the 6550's on the right side have that blue glow while the ones on the left glow but not blue (just orange). Steve, thanks for your help. It's a little intimidating dealing w/ expensive tube equipment the first time around:(

Chris

P.S. Will I damage my amp by playing the right channel only?

Seeing as it probably isn't the tubes at this point, don't fool around with it anymore until you call Cary: 919-481-4494, Ask For Kirk and explain your problem. Why risk damaging your unit or other parts of your system at this point? It should be under warranty so let them worry about it .

[Paul Chang]

Originally posted by Chris M
P.S. Why do my Russian 6550's have a blue glow to them?? The blue glow is more than likely caused by the electrons hitting some object at high velocity. I found this on a Svetlana web page http://www.svetlana.com/docs/tubeworks.html

C. Blue Glow -- what causes it?

Glass tubes have visible glow inside them. Most audio types use oxide-coated cathodes, which glow a cheery warm orange color. And thoriated-filament tubes, such as the SV811 and SV572 triodes, show both a white-hot glow from their filaments and (in some amplifiers) a slight orange glow from their plates. All of these are normal effects. Some newcomers to the tube-audio world have also noticed that some of their tubes emit a bluish-colored glow. There are TWO causes for this glow in audio power tubes; one of them is normal and harmless, the other occurs only in a bad audio tube.

1) Most Svetlana glass power tubes show FLUORESCENCE GLOW. This is a very deep blue color. It can appear wherever the electrons from the cathode can strike a solid object. It is caused by minor impurities, such as cobalt, in the object. The fast-moving electrons strike the impurity molecules, excite them, and produce photons of light of a characteristic color. This is usually observed on the interior of the plate, on the surface of the mica spacers, or on the inside of the glass envelope. THIS GLOW IS HARMLESS. It is normal and does not indicate a tube failure. Enjoy it. Many people feel it improves the appearance of the tube while in operation.

2) Occasionally a tube will develop a small leak. When air gets into the tube, AND when the high plate voltage is applied, the air molecules can ionize. The glow of ionized air is quite different from the fluorescence glow above--ionized air is a strong purple color, almost pink. This color usually appears INSIDE the plate of the tube (though not always). It does not cling to surfaces, like fluorescence, but appears in the spaces BETWEEN elements. A tube showing this glow should be replaced right away, since the gas can cause the plate current to run away and (possibly) damage the amplifier.

[Steve Hoffman]

Well, some of us think that if a tube glows blue, it doesn't have a good vacuum seal.

:rolleyes:

[Paul Chang]

I just edited my previous post on glowing tubes by adding the paragraph concerning leak. Svetlana states the glow from ionized air molecules in a leaking tube is "a strong purple color, almost pink'. They also have these to say in that "glowing section".PLEASE NOTE: some older hi-fi and guitar amplifiers, and a very few modern amplifiers, use special tubes that DEPEND on ionized gas for their normal operation.

-Some amps use mercury vapor rectifiers, such as types 83, 816, 866 or 872. These tubes glow a strong blue-purple color in normal use. They turn AC power into DC to run the other tubes.
-And occasionally, vintage and modern amplifiers use gas-discharge regulator tubes, such as types 0A2, 0B2, 0C2, 0A3, 0B3, 0C3 or 0D3.

These tubes rely on ionized gas to control a voltage tightly, and normally glow either blue-purple or pink when in normal operation. If you are unsure if these special tubes are used in your amplifier, consult with an experienced technician before replacing them.

ALSO NOTE: these light sources cannot be seen in metal-ceramic tubes, because their parts are opaque. As we said above, it is difficult to tell if a ceramic tube has become gassy. Usually, in a large radio transmitter, a gassy tube will arc over internally. (This does not damage the transmitter. It has protective circuits.) The equipment operating manual should give more information on this.

My take on the whole glowing business is that a vacuum cannot be excited by fast moving electrons. There is nothing there. However, certain types of tubes may have some gas put in them by the manufacturers. If the tube glows, something has been hit by the electrons. Is it normal? It depends on what gets hit, be it impurities, air or inert gas, and a spectrum analyzer should be able to tell.

[cjk1026]

Originally posted by Steve Hoffman
Well, some of us think that if a tube glows blue, it doesn't have a good vacuum seal.

:rolleyes:

Is this true? My WE 300B's have a slight blueish glow that is only visible with the lights off. I always thought this was normal. Plus it looks kinda neat. Any responses?
Chris

[Steve Hoffman]

Probably is normal.

But, how old are your 300B's?

All tubes lose their vacuum sooner or later....

[cjk1026]

My Western Electrics are 8-10 months old and have glowed slightly since new. I've read many articles that talk about this as normal. Thanks for the reply.

[Steve Hoffman]

Yeah, don't sweat it! Normal.

How do they sound? You like them?

[cjk1026]

To me, differences in tube sound are very, very slight. The Western Electric 300B's however, sound somewhat more than slightly better than other 300B's I've tried (Sovtek, Chinese no name, J&J). And yes, they seem to match my system very well. There seems to be something to the "tubes & horns" so many people are getting into these days. Yesterday I was at a high end audio store in Santa Monica looking for record cleaning solution (after a foray at a vinyl shop). While waiting for help I listened in on a couple of demonstrations that were going on. One couple was listening to a very expensive B&W (Nautilus 802's & 803's), Krell (FPB600), Theta (cdp/dac) system with obvious mega buck cables. It sounded pretty darn good. But, imho, not as good as my rig at home.
Chris