Tube broke during voltage check

[Tonydatigerr]

I was about to begin testing voltages and did the things listed before actually beginning in the manual on pg. 38. My tubes were glowing and heating up so I presumed I was good to go, I flipped the chasis over and started measuring. The first few terminals were good, then I noticed that the numbers were way off. I flipped the chassis back over and noticed that the top of my 12AU7 was charred and was no longer glowing nor hot. I'm at a loss right now, won't have any music for a while since I just sold my amp to build this

edit: My resistance check came back with the same numbers as listed in the manual - could that mean I just got a bad tube or am I dumb?

 

[Paul Birkeland]

I think you ought to post a picture of what you're referring to.

A bad tube will have a milky white residue on the inside. 

You could also post all your voltages, that will give us a clue as to what's going on. 

 

[Tonydatigerr]

http://i.imgur.com/NLNj4eF.jpg

Sorry for the potato camera phone picture. I am measuring voltages now.

edit: When I give power to the amp while it is upside-down, the big tube glows purple and starts to spark and I am afraid to keep going.

 

[Paul Birkeland]

The little tube looks perfectly healthy.

If the 6080 is sparking, it's very likely that the octal socket was installed incorrectly. 

 

[Tonydatigerr]

I just double checked with the picture in the manual and everything lines up. Is there anything else that looks incredibly wrong?

http://i.imgur.com/BM6wOX2.jpg

 

[Paul Birkeland]

The B2/B3 connections look like they could touch with very little prodding.  The wire going to B3 should be pulled closer to the tube socket pin, or the jacket should be moved to avoid this.  (Look at your B1/B6 connections - those look great)

The leads of the 3K resistors that would attach to 7/9 have been left way too long, and could short to terminal 8, which will do very, very bad things to your amplifier.  They also look like they might be attached to 6/10 instead of 7/9?

The red wire leaving B8 has an awful lot of exposed lead, I would pull it closer to the socket pin.

You can run the amp without the 6080 and take readings on terminals 1-5 to check the 12AU7.

-PB

 

[Tonydatigerr]

Will do, thank you so much for the help so far!

 

[Tonydatigerr]

Here are my revisions - the sparking in the big tube is persisting though.

http://i.imgur.com/3R9rSMf.jpg

 

[Tonydatigerr]

And here are the voltages for terminals 1-5 without the 6080

1: 115
2: 222
3: 0
4: 222
5: 109

 

[Paul Birkeland]

It looks like your 12AU7 is working well. 

It's possible that the 6080 encountered some damage during shipping.  You return the tube to us and we'll swap it out for you.

-PB

 

[Tonydatigerr]

Will I only need to pay for shipping one way and should I put a note into the box asking for an exchange?

 

[Paul Birkeland]

Shoot an e-mail to replacementparts(at)bottlehead(dot)com and we can hammer out the details.