Audio Technica AT-ML150/OCC - Too Old?

I just purchased an "NOS" at-ml150/occ and installed it.

When the material is easy to track, it sounds pretty decent, maybe a little lean and very "glassy" - lots upper midrange/lower treble hardness. Trumpets, Vocals, and other "difficult" things cause major sibliance at 1.25-1.75grams.

I'm using a fluid-damped tonearm that completely alleviated mistracking in two other cartridges, so I'm wondering..

Could this cartrige just be old and the rubber parts so dried out that it just isn't good any more? Or Something else? Old stylus maybe?

Interested in your opinions. I will post a needle drop if that helps.
specifically what arm are you using and how many hours under the cartridge up to now?
Line contact stylii are pretty fussy about VTA, I would start there. Are you using Baerwald alignment or some alternate math?
I'm using the technics 1200 arm with the KAB fluid damper (and cardas rewire).

The cartridge has about 2 hours of use so far. It has been suggested that I haven't let it break-in yet, but should it sound this bad to start with?

The VTA looks pretty spot on, as far as the arm being parallel with the platter, but I'll play with that.
Grab a test record with low frequency resonance tones and figure out the static compliance of the cart with the dampener engaged. If it's *way* off - which for ATs is probably anything under 20cu - you might want to consider getting a new cart.

BTW, some people recommend not using any cart with a suspension over 5-10 years old, simply because the rubber can wear out that quickly. I don't think anybody's provided any concrete evidence one way or another, but you might want to keep some kind of beater cart around to swap back and forth with the 150MLX, in case the cart is causing real damage and you need to test with another cart to be sure.

FWIW, I never experienced any sibilance with either my 440ML (the original! not even the MLa!) or the OC9 on my 1200.
I just tried out a current 150mlx. I gave it about five hours and sent it back. I found it a very unsubtle cartridge with shrieky highs, indistinct lows, and a coloured midrange. Maybe great for a shut in, laid back system but not for an already reasonably revealing one. Perhaps I should have given it more time to break in but it just wasn't showing any promise.
Dear Joelv: I own two of its " big brothers " the AT ML/170-180 and owned the 150 and for what I remember I don't had that kind of trouble with the cartridge that btw is a good one.

About the " rubber parts " on cartridge's suspension over the years ( in many old MC and MM cartridges ) I never had troubles about and your is a NOS so I don't think that the trouble is in there but I can't be sure.
++++ " Old stylus maybe? " ++++, I don't think so either because your cartridge is new.

+++++ " The cartridge has about 2 hours of use so far " ++++

well you like Bri an or any one else can't think that 2-5 hours is enough time to make a precise judgement IMHO that cartridge or any other one needs more time.

Other subjects are to be sure about the right cartridge set up: VTA, Azymuth, VTF, overhang, load impedance, load capacitance, etc, etc. and this set up you can't do it till the cartridge suspension settle down ( about 20-30 hours ), your initial set up is only that a set up to start but not to evaluate the quality cartridge performance, so you need to have a little more patience about. Even after those 20-30 hours and with the right sey up you need to know if your tonearm is a good match for it, you can try here with different headshells and different wire headshells and og course with the tonearm damping and always could be a trouble with the quality on the phono stage, specially when we grow up/improve with a better cartridge.

Regards and enjoy the music.
Yeah, well NOS is in quotes above because neither the seller nor myself are the original owners. I just wondered if it had been used.

I will patiently play some records and see what happens after 20-30 hours.
can't speak to the condition of the nos cartridge, but i have several cartridges, including benchmark designs by lyra and london-decca. the AT 150x plays with those and more.