What happened here?

I think bob's right that it's not a newton ring thing and if the collar has let loose somewhere that would explain why your rainbow colors look different than the other day.

Possibly. I'll check it when I get home tonight. But it went from having minimal newtons close to the edge, to the whole head having them. I think the bottom layer snapped out of the collar - it has that nice dead muted Evans hydraulic sound. Perhaps the Pinstripe solved that issue by using the pinstripe to adhere both layers together?
 
I'd be willing to bet that a ply has just slipped a bit from the collar. I've had this happen with another brand of head. You couldn't really tell what was wrong (other than the sound) until you took the head off the drum. Then you could tell that the bottom ply was looser than the top. It totally killed the sound.
 
You couldn't really tell what was wrong (other than the sound) until you took the head off the drum.

Just realised I didn't actually mention this before when I said it would be easy to spot. Truth is, I didn't consider it as I thought it would be stating the bleeding obvious.....but it's prompting me to ask the question nonetheless. Bo, tell me you've actually taken the head off the drum? If you're trying to asses issues with the head whilst it's still on the drum, we're never gonna let you live this one down!! :)
 
Just realised I didn't actually mention this before when I said it would be easy to spot. Truth is, I didn't consider it as I thought it would be stating the bleeding obvious.....but it's prompting me to ask the question nonetheless. Bo, tell me you've actually taken the head off the drum? If you're trying to asses issues with the head whilst it's still on the drum, we're never gonna let you live this one down!! :)

No it's off the drum. I already changed it out and then rushed out the door to get to work. So I won't be able to really look at it until I get home. I'm gaining much from the theoretical discussion, though. It'll point me in some directions when I actually do get to see what may have happened.
 
I'd go for the Newton's Rings theory. These are a phenomenon that is caused under specific circumstances. First you need two parallel reflective surfaces in very close proximity. There has to be some air trapped between the surfaces.
Then if light shines through both surfaces and various other factors are present then you can get Newtons Rings.
I know about this because it's an effect you get in a photographic enlarger. It is caused when air is trapped in the glass plates of the negative carrier and the image is projected onto the print thus ruining it.
So the point is, there must be air trapped between the surfaces of the head.
So air is getting in somewhere.

Sherlock :)
 
Well, upon close inspection, I could find no evidence of the bottom ply pulling out. Perhaps Bob is right and it's just condensation between the plies that will hopefully dry out. But you know how you can tap the head when unmounted and hear some kind of tone? Well, this one sounds totally dead and much lower in pitch then the new one which rings at a higher pitch. I'm flummoxed. No damage to the collar (unless the glue broke inside the collar and you can't see where its gotten loose).

I put it in the box and out in the garage where it can enjoy some dry heat for a few days.
 
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