Is this arcing?

[tea_hous]

I'll try it when I get back -- probably with a 'sacrificial' set of speakers attached. I can't make any progress for now .

 

[egellings]

Hey everyone... been a long time since I've posted to AK :0. I'm here seeking some input from those who have more knowledge and experience with tubes than myself.

I just purchased a Yamamoto A-08s, and one of the tubes was damaged in shipping (despite being packed very well). Its an '80' rectifier, presumably from the 1930's or 40's. After carefully setting everything up, I powered it up for the first time, and immediately noticed something awry. I shut it off after a couple seconds. Then, a couple days later, I decided I needed to try it again to get a better assessment of what was happening, and employed by wife as a videographer for the event . This time, I ran it for about 30 seconds before powering it back down.

So, It's obvious that the tube needs to be replaced -- I'm already searching, and luckily they aren't that expensive either. What I'm posting this for is twofold -- I'm fairly inexperienced with tubes, so I want to educate myself in knowing whether I was witnessing arcing or something else. I'm also concerned that if it actually was arcing, that there may be damage to something else in the circuit, such as those expensive transformers or the hand made capacitors .

The fuse did not blow, and there were no loud noises coming from the tube that I assume would accompany arcing (popping, crackling, etc.). It almost looks like the tube has become very gassy and / or broke a filament, which may be why the left plate is glowing so brightly (?). I'm not sure -- maybe the flashing we see at the very beginning has to do with the gas being 'excited', or somehow burning off, but not actually causing any electrical arcing? I do notice that the gas seems to 'thin out' immediately when the tube flashes a few times on initial power up...

Thanks everyone for any and all input!

It looks like air got in there making the tube glow uniformly like that. It's toast. Type 80 is a full wave high vacuum rectifier, like a 5Y3.

 

[tea_hous]

Thanks for the input! We're long passed that hurdle, as the thread and time progressed.

 

[tea_hous]

I wanted to post a 'conclusion' to this long saga. The last issue that I was having was a slight intermittent / inconsistent channel hum... so slight that it couldn't be heard from the listening seat, but I can't help but to be a fussy audiophile . I eventually solved this issue as well.

After digging through a heap of forum posts around the subject, I realized what I was hearing most closely matched to what people describe hearing when their tube pins are a little dirty. At first I thought, 'Nah, can't be that - I thoroughly cleaned every pin with isopropyl and q-tips when I first received them'. Yet, as I read, I opened to the idea that perhaps I needed a little more cleaning power than my isopropyl provided. So, based on the endorsement of other 'tube guys', I decided to buy some Magic Eraser to thoroughly clean all my pins again. I figured it's a low cost and low risk attempt, so I'll give it a go.

Bullseye! To my surprise, this actually was the issue. After cleaning everything and firing the amp back up, the hum I was hearing is completely gone. Now my background is completely black, on the level of SS gear... just as hogwylde09 had described with his A-08s.

I figured I would conclude the thread with this bit of information in case an onlooker with a similar issue finds their way here. Cheers and thanks again everyone -- happy listening!

 

[egellings]

Hey everyone... been a long time since I've posted to AK :0. I'm here seeking some input from those who have more knowledge and experience with tubes than myself.

I just purchased a Yamamoto A-08s, and one of the tubes was damaged in shipping (despite being packed very well). Its an '80' rectifier, presumably from the 1930's or 40's. After carefully setting everything up, I powered it up for the first time, and immediately noticed something awry. I shut it off after a couple seconds. Then, a couple days later, I decided I needed to try it again to get a better assessment of what was happening, and employed by wife as a videographer for the event . This time, I ran it for about 30 seconds before powering it back down.

So, It's obvious that the tube needs to be replaced -- I'm already searching, and luckily they aren't that expensive either. What I'm posting this for is twofold -- I'm fairly inexperienced with tubes, so I want to educate myself in knowing whether I was witnessing arcing or something else. I'm also concerned that if it actually was arcing, that there may be damage to something else in the circuit, such as those expensive transformers or the hand made capacitors .

The fuse did not blow, and there were no loud noises coming from the tube that I assume would accompany arcing (popping, crackling, etc.). It almost looks like the tube has become very gassy and / or broke a filament, which may be why the left plate is glowing so brightly (?). I'm not sure -- maybe the flashing we see at the very beginning has to do with the gas being 'excited', or somehow burning off, but not actually causing any electrical arcing? I do notice that the gas seems to 'thin out' immediately when the tube flashes a few times on initial power up...

Thanks everyone for any and all input!

Likely that air leaked into that 80. It's shot.