Mesa 2:90 tube concern

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vitod
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Mesa 2:90 tube concern

Post by vitod » Sun Dec 09, 2012 2:11 pm

Hi all!

Looking at the tubes, right side, lower left, the tube is the only one that has a super RED HOT glow! :shock: The amp just doesn't sound good at all. Is this a common problem and what can it be? I checked the pre tubes and they're fine. I also switched the tube with other 6L6's and same result. What gives?

Thanks

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elvis
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Re: Mesa 2:90 tube concern

Post by elvis » Mon Dec 17, 2012 12:32 pm

Red glow is usually the filament, not the plate. The plate is generally blue.

You may have a problem with the filament circuit (like a short), and the other tubes may not be getting hot enough.

If the red glow is plate, then you have a serious bias issue on that tube.
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