"93.75kHz and 46.875kHz are the sampling frequencies Bruno Putzeys uses in all his digital products for Hypex, Grimm audio, KII, etc.", as outline here[0], for the following reason:
5.2 Clock
The clock circuit is the same as that used in the CC1
except that the sampling rate is set to 93.75kHz instead
of one of the more traditional audio rates. This is specifically
done to improve the performance of the SRC chip.
An uncommon clock frequency reduces the odds that mix
products between the incoming clock and the internal
clock fall inside the PLL loop bandwidth of the SRC.