New Prima Luna Amp In Distress / Me Too

thanks newbee,,loving my prima one,,currently still using stock tubes ,,but I am getting the itch to roll,,maybe the cv4004 mullards,,and maybe slvania 12ax7 ,,then we'll see about output tubes later ,,thanks bro.
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It’s been a few months since the original faulty tube has been swapped out with a replacement KT-88 sent by Upscale Audio. Things sailed along smoothly until last week when another stock KT-88 tubes began popping and demonstrating the same problems.
After checking with Kevin at U.A., he suspected it might be vashode powder. On close examination, this turned out not to be the case (at least, as far as I can tell).
At any rate, since this latest intermittent failure began in the same socket as the first one, I’ve decided to replace the entire power set to rule out any “hot seat” factor that might be emanating from the amp while it’s still under warranty. I’m going with Valve Art Kt-100s which are a rugged Chinese copy of the old Genolux design KT-88.

Whether this ends up to be just an unlucky set of stock tubes or a problem with the Luna, I’ve come around to thinking that this may be the challenge that one sometimes has shoulder in tube audio.

It should be noted that Kevin reports that, outside of a few PL Kt-88s demonstrating a similar problem with Vashode powder (none in the PL-EL-34s), the Prima Luna Amps are demonstrably good builds with few problems. In fact, I’m not in a panic about all this – learned a lot about this amp through troubleshooting – learned also that when it’s on song, it’s absolutely warm and lush and competes with the best of ‘em.

Tell me more about the blue glow? I know this is an old thread.
I want to see it.

In summary blue gaseous glow in power tubes is good, and pretty. Lack of it is neither unusual nor indicative of anthing bad to come.

For a detailed explanation of the reasons go to Audio Asylum and look at their FAQ's. I'm too lazy to explain.

In summary blue gaseous glow in power tubes is good, and pretty. Lack of it is neither unusual nor indicative of anthing bad to come.

OTOH I recently had a blue gaseous glow on start-up in the lower part of a new NOS 5AR4 rectifier tube. I should have known something was wrong as it had just glanced the needle ever so slightly upon testing for emissions on my tester. It was so slight I didn't think much of it until I saw the glow, and then heard the occasional popping sound in that channel once the amp was up and running. Swapped out the tube and no popping sound. Turned out it had a hairline crack at the base. I don't know if the blue glow had anything at all to do with it, but I'd never before noted any blue glow at the base of a rectifier tube before this. You tell me. The (ebay) seller of the tube refunded my purchase.