Tube smell?

Some 5687 tubes I just installed have a mild but definite
burning-rubber odor. It's not extreme, but it is there
if you sniff around them (and I can also detect it around
the room). Has anyone ever had this? Could it be something
oxidizing because they are newly installed?

It's a bit hard to tell, but it seems to be all 4 of them,
not just one.

The tubes work fine, but look brighter than
my old cheaper 5687s. They sound absolutely great,
nice and smooth and mellow.

It's not the amp, as the old tubes don't smell.

Thanks for any help.
Could it be a bad tube and a resistor burning? Happened to me.
I bought a tube preamp from someone that smoked cigars and ended up getting rid of it because it stunk up the house so bad when I turned it on.
Maybe the preamp was built in Cuba.
On the PrimaLuna amps, as I think Art Dudley noted at one point, the stock tubes have kind of a smoky smell when they warm up. If you have to put your nose right up to the tubes to smell it, I wouldn't worry too much. If you can smell it from your listening chair, then maybe it's time to replace the tubes -- or have the entire unit checked out.
Part of the charm of tubes. Mind you it is subjective only and cannot, indeed need not, be explained scientifically, but the sense of smell is involved in the emotional response to music.
Sounds like a lack of engineering foresight. 5687 tubes have a larger cathode than typical small signal tubes. They run hot and are probably melting the circuit board or an adjacent passive component.
Thanks everyone. The aroma has been reduced significantly
after about 8 hours of use, but is still present near the amp.
It is definitely the tubes, not the amp, as the tubes
are fully exposed atop the amp, and the original Phillips
tubes had no smell at all, even close up. These are
Tung-Sols. Yeah, I guess I'm with Pbb's comments above,
and I'll need to learn to love it. Boy, these TungSols
sound amazing--mellow and smooth but soooo non fatiguing,
really magic.
could it be that you have counterfeit tubes? if that's the case the ink they used to relabel the tubes may be burning off and projecting that smell.
Sounds weird, but it is remote possibility......
There was probably something deposited on the glass. I have seen this with NOS tubes many times. If I were you I would pull the tubes and wash them carefully so that the glass is squeaky clean. Use only the slightest amount of dish soap. Avoid getting water on the base.

Dry the tubes carefully before reinserting them in the amp!

Its a good idea to clean the envelopes in this way at least once every year. Dust and fingerprints (and smelly rubber contaminants) will shorten the life of the tube due to heat. The tubes will get rid of their heat most effectively if the envelopes are clean.
Hey Atmasphere--Thanks!! I rubbed them with
a damp tissue and it actually worked! There is
now only the slightest aroma very close up.
It may have been just one of the four, but
I cleaned them all. I really appreciate your help.
Now my wife won't complain.
tube smell??? I LOVE IT!!!!
Me too.

The Baby amp from Sophia has a really cool smell. I have had 3-4 different ones over the years and they all smell the same.

Charm of tubes...
My tubes don't smell, something's wrong...wahhhhhhh!
I just put a fresh quad of Shuguang KT88-98 tubes in my VAC amps and for the first 8 hours or so, they had a distinctive odor to them. The odor gradually faded away.
Thanks again everyone.
The smell is gone.
(Was that a BB King Song?...)
Is the smell matched? ;>). Only kidding, Don't risk creating a problem, get rid of them pronto, only bicycle tubes are supposed to smell like rubber.
I've always thought "tube smell" was dust burning off. I enjoy the tube smell from my vintage gear.
The aroma disappeard after a day or two.
Thanks for everyone's help.
'love those Mullards!