Low volume / Power cutting out on Sprout's Vinyl input?

Purchased a Sprout100 a few months back and been using it primarily for streaming audio. I hooked up one of my turntables (Music Hall MMF 2.2) a few weeks ago and gave it a spin. The volume was very quiet on the vinyl input, about 50% of what I hear when I switch to the Digital input. Also, if I crank the volume on the vinyl input, the power cuts out about 75% of the time and I have to power up again. Had some free time today so tested to rule out a Turntable issue and hooked up my Technics 1200 and I get the same results. Played Etta James “At Last” on LP and on Amazon HD Streaming and flipped inputs back and forth, and the vinyl input was barely audible when the Digital input was what I consider to be normal listening volume. Amp is running to a pair of Klipsch reference speakers. Are there any known steps to fix this, or is this the expected behavior for a connected turntable? Thanks.

I have the Sprout hooked up to a Pro-Ject Debut Carbon USB turntable. The pre-amp is in the turntable and I connected via the RCA input to the Sprout. I notice that this is considerably lower volume than the USB input from my media computer. I have not used the phono input on the Sprout, but I may hook up an old Connoisseur turntable sometime.
So, I think I can confirm the general volume difference between audio-in and digital-in.