The AT155 has the same 490mH generator as the modern 440/120. I see the 440 replacement stylus went up another $50. For another $25 or so you can get a 150MLX stylus. This is a great combination with the 490mH motor, reminiscent of the 160ML.
The Signet TK5Ea, 7Ea, 7LCa, all have 550mH generators. All the beryllium styli (7LCa) are extremely rare. If you're looking, there are models like 152LC/ML and Signet MR5.0 LC/ML. These have the same fitment. The 440MLa stylus has a bump at 16KHz - might be a perfect match for the 550mH motor, I don't know. All of that series will fit. BTW, AT has a new "B" version of the 440/120. The generator appears the same.
Regards,