ART sells a USB-powered phono preamp. its very flexible, as you can use it as just a ADC,
ADC+preamp, DAC, preamp, etc.
its about 99, and i think the best solution here. but then i have one, so maybe im
biased?
i havent acrtually tested to see if it works with snd-usb-audio (probabyl does) as i just
use a 1/8" cable to an indigo io