Line Input clipping (red)

[thumb5]

Your maths is correct (I think) but bear in mind that the 6.5 mV sensitivity, and hence the 1.7 V output level, is rms at 1 kHz. I would expect peaks to be much higher than this, depending on what you're playing - presumably not a 1 kHz test tone?

Is it possible to reduce the gain in the phono stage?