Crack: hum and pops, twice the voltage readings of the manual

[ffivaz]

If I try to touch, turn or just tap the 6080 tube, the screeching fades away or grows stronger. So it looks like there is something around there. The glass from the tube is "loose" from the black bottom plate and there is something moving inside, apart from the problem posted in the picture posted above.

I'll try to find a replacement tube.

[Paul Birkeland]

I'd grab a wire brush and clean the tube pins off, that should help.

I'd also do the chop stick test on each solder joint on the 8 pin socket. 

A loose envelope and debris in the tube is generally not an issue, especially with a tube as rugged as the 6080.

[ffivaz]

Well, looks like the 6080 tube was bad. I just received a new one from England and my Crack just works without any  pop !

Thanks for your help.

PS : I think I'm addicted to BH, I just ordered a Reduction kit, looking forward to build it