From what I can see online (Rogue Owner's Manuals) the Tempest & Tempest II do not feature an internal phono circuit, just a line level input labeled as such?
While not familiar with the U-Turn tonearm specifically, cartridges do respond tonally to differences/adjustments of Vertical Tracking Force. On some systems, tracking force can vary dramatically when measured at distances other than actual record level.
Given the Ortofon 2M Red recommends a VTF of 1.8 grams + or - .2 grams, you may try lightening a bit. Treat the counterweight like an old-school single knob electronic tone control where less weight accentuates the highs and conversely, more weight emphasizes bass. Adjust to where it sounds right on your system.
While not familiar with the U-Turn tonearm specifically, cartridges do respond tonally to differences/adjustments of Vertical Tracking Force. On some systems, tracking force can vary dramatically when measured at distances other than actual record level.
Given the Ortofon 2M Red recommends a VTF of 1.8 grams + or - .2 grams, you may try lightening a bit. Treat the counterweight like an old-school single knob electronic tone control where less weight accentuates the highs and conversely, more weight emphasizes bass. Adjust to where it sounds right on your system.