For a noticeable upgrade in SQ, you need to move up to the Grado Gold. I'm assuming you haven't experienced any hum with your Thorens, so the Gold would be the way to go. The Grado Black and Gold carts are not insulated so they can pick up motor noise from certain brands of TTs.
As long as your current TT setup does not hum when the tonearm moves toward the center of the record, then you can move up the Grado line.
http://www.needledoctor.com/Grado-Gold1-Prestige-Series-Phono-Cartridge?sc=7&category=926
The Ortofon 2M Blue is in the same league as the Grado Gold, and is very widely respected. It has a different sonic signature, not as warm as the Grados. Either cart would take your analogue setup to a higher level considering your budget.
One more...a Denon high output MC cart may be the best bang for the buck. It's output gain will match a MM phono stage.
If you change to a different brand, you'll need to take into consideration the compliance of the cart. IOW, you need match the mass of the tonearm with a cart of the proper size.
As long as your current TT setup does not hum when the tonearm moves toward the center of the record, then you can move up the Grado line.
http://www.needledoctor.com/Grado-Gold1-Prestige-Series-Phono-Cartridge?sc=7&category=926
The Ortofon 2M Blue is in the same league as the Grado Gold, and is very widely respected. It has a different sonic signature, not as warm as the Grados. Either cart would take your analogue setup to a higher level considering your budget.
One more...a Denon high output MC cart may be the best bang for the buck. It's output gain will match a MM phono stage.
If you change to a different brand, you'll need to take into consideration the compliance of the cart. IOW, you need match the mass of the tonearm with a cart of the proper size.