The MC Gold has an output of .4mv. This combined with the P75 gives a total output of just 575mv.
That is not the maximum output, it is the output with a standard test track. The maximum is higher so it could well be that it will drive an amp with .8V sensitivity to clipping especially on a hot record.
You also need to be concerned about the low input impedance of the amp. If you get a typical passive with an impedance of 10K or so the phono stage will see that and the 10K of the amp in parallel for an effective impedance of around 5K at higher volumes. I couldn't find a spec for the output impedance of the phono but it it is on the high side, say >500 ohms your sound will suffer.
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