Tube help
heiney9
Posts: 25,079
There seems to be an issue I've never encountered before with a European ECC82. The tube heater flashes upon start-up like many Euro tubes I own, so that's pretty normal.
But instead of flashing and dissipating , the (heater ?) wire continues to glow red and the tube envelope gets much hotter than it normally does in the area that is glowing. The sound output from the tube is very weak. I tried it in both the left and right position in my pre-amp and get the same result.
Obviously there is an issue but maybe someone can explain what's going one?
Thanks
H9
But instead of flashing and dissipating , the (heater ?) wire continues to glow red and the tube envelope gets much hotter than it normally does in the area that is glowing. The sound output from the tube is very weak. I tried it in both the left and right position in my pre-amp and get the same result.
Obviously there is an issue but maybe someone can explain what's going one?
Thanks
H9
"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
Comments
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You let the magic smoke out.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
My god man test it on something other than your gear. Guessing maybe a short.. ..heck i don't know
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Yeah, and once the magic smoke is gone............no more tube magic."Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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English smoke isn't too hard to find, thanks to a still-thriving restoration market.
... but metric smoke? That's gonna be a problem to source.
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You probably have a shorted tube. Some B+ is conducting from the plate to the filament. Do you know someone with a tube tester? If not, you can improvise. I have a few ideas for you. Start with a couple of alligator clips and a power supply or car battery. Power pins 3 and 4 with a DMM set up for D.C. Current. It should Draw 150ma at 12 v. Does it glow red under this condition? Can you see where we're going here? If it acts normally here and badly when powered up with B+ on the plate, you've got reason to believe it's shorted. That's gonna be a problem in circuit. You could also check for continuity between the plates (pins 1 and 6) and the filament while tapping the tube. A positive test is significant but a negative result is inconclusive.The world is full of answers, some are right and some are wrong. - Neil Young
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Thanks dcmeigs,
I bought this particular tube from a well known vendor to me. It's from Germany and is a rare lp Hamburg tube, so I paid a good amount for it. The seller, whom I trust, swore the tube tested strong and no shorts, etc. I did get a refund because I've made several purchases in the past 6 years from her. Even though there is a no return policy. She said to keep the tube also.
I'd still like to see what's wrong with it.
H9"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
