The Audio Technica cartridge is a great cartridge. Truly one of the best buys in hifi. That being said...
Are you sure your cartridge needs replacement? Looking at the gear you have listed, I'm not sure the cartridge is the weakest link. The K9 may not be Linn's best cartridge, but its certainly a good one. The NAD PP2 is the obvious weak spot IMO. Its good for the money, but really nothing special at all. I owned one for about two years and moved on. I'm not bashing NAD; I owned their gear for years and it has always been a great value for the money. I think the PP2 is probably the weakest component in their line up though. To my ears, it sounds slow, flat, closed in, overly warm and smooth, and is a bit noisy. On a positive note, it doesn't try to go to high or low in the frequency range, and sounds pretty controlled.
Personally, I'd look into a new phono stage if the cartridge doesn't need replacement. If the cart is worn, replace it, then look into a new phono stage. Changing your cartridge may not give you much improvement. Your current gear is a bit too good for the PP2. Its definitely the bottleneck right now IMO. Some far better phono stages for relatively cheap are Cambridge, Pro-Ject, Rega, and Bellari. I'm sure others may add to the list. They all sound different.
Sorry if I side tracked the conversation.
