I have a Koetsu Rosewood cart on my FatBoy and I was reading an interesting article that states these carts want around 18g effective mass. Is there a way to increase effective mass for FatBoy arm?
Yes, you can add a 3g headshell weight to the Fatboy.
I have a Rosewood Signature that I swamp between a Fidelity Research 64s and the FB Gimbal and the Rosewood performs equally well with the FB. I would also recommend the third pivot accessory with the FB Uni when using any low compliance cartridge
It can be used both ways. If placed between the cartridge and headshell, you will need to re-adjust your vta/sra. The weight placement "may" have a different sound due to the change in the cartridge / tone arm damping interface.
The Headshell @Brf linked is exactly what you could do. You could also use the larger screws by Soundsmith. The Koetsu Rosewood is a great cart!
Yes, you can add a 3g headshell weight to the Fatboy.
I have a Rosewood Signature that I swamp between a Fidelity Research 64s and the FB Gimbal and the Rosewood performs equally well with the FB. I would also recommend the third pivot accessory with the FB Uni when using any low compliance cartridge