>>The tracking force is set at 3.5. According to the Mitchell literature, doing so deactivates the spring.<<
Correct. The spring applies upward force in Rega arms, not a downward force. But deactivating the spring means that you have to move the counterweight further from the pivot. If you want to operate with the spring deactivated, you'll have to add more mass to the counterweight to move it closer to the pivot.
FWIW, I use a Expressimo Heavyweight on my Townshend-modified Rega and with the Lyra Helikon tracking at 1.8 g. I have the counterweight hanging off the end of the arm tube as far as it can go. If I used a heavier cartridge or more tracking force, I'd have to add mass to the Heavyweight.
Correct. The spring applies upward force in Rega arms, not a downward force. But deactivating the spring means that you have to move the counterweight further from the pivot. If you want to operate with the spring deactivated, you'll have to add more mass to the counterweight to move it closer to the pivot.
FWIW, I use a Expressimo Heavyweight on my Townshend-modified Rega and with the Lyra Helikon tracking at 1.8 g. I have the counterweight hanging off the end of the arm tube as far as it can go. If I used a heavier cartridge or more tracking force, I'd have to add mass to the Heavyweight.