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Is the red glow normal for 845 tubes?

Hope to get some help about the red glow from a Bel canto SETi 40 845 tubes. Is this red glow normal? Do this tubes (Sino graphite plate) suppose to glow red after about 25-30 min. After turning off the amp the glow last a couple of minutes. I am just worried that the tubes may get damaged or the amp itself. Is this glow the result of the tube dissipating heat? I know this tubes suppose to dissipate about 70W and I worried that the amp "tries" to dissipate more heat that they can handle. Thanks in advance for your help.
tiofelon
tiofelon OP
59 posts
 
Thanks again Brf. I just run into an article in VTV (vacuum tube valley) where it says "graphite es heat-resistant (in fact, it can operate with a dull red glow for a long time without failing)" in power tubes like the 811 o 845. However a new set of 845 tubes is coming my way.
stanwal's avatar
stanwal
3,147 posts
 
Red glow in morning, audiophile take warning! Sorry, sometimes I just can't help myself.
tiofelon OP
59 posts
 
I just got an answer from Mathew Cramer from Bel canto. He says that "the red glow is normal for this type of design" (SETi 40). So that settles everything down. Thank all for your help. Tiofelon.
brf
1,715 posts
 
What did he say about using a low dissipation (70w) 845s in the SETi40? That is the real question you should ask. If the SETi845 is auto biased for a standard 845, then the amp is over driving the Sino.
tiofelon OP
59 posts
 
Good point Brf! He did not said anything regarding the low dissipation. I will ask him if the SETi 40 is biased for a standard 845 tube (100 W dissipation).
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