slide in phono stage for Accuphase C-2450 preamplifier - is it any good?

think long, I suspect nearly everyone will recommend keeping your phono stage separate.

also, thinking long, think both MM, MC, and optional gain and separate optional loading. Perhaps multiple inputs for two or 3 tonearms, and Pass for MM

Good point - thx.  The slide in units are not inexpensive, and the choice of separates would be much greater.

But given how Accuphase is meticulous in their design, engineering, and production, I am still wondering how the AD-2850 or AD-2900 perform in an Accuphase preamp such as the C-2450.