Diy Adc

The adc chip vendors (all vendors actually, not just adc ones) will sell you an evaluation board, aka "reference design" intended for a budding engineer to copy, "copy this and it WILL work" note the boards need a power supply, hopefully a power supply is not too much of a stretch for you.

For easy of simplicity, a crystal semiconductors evaluation board would be a good choice.

The eval board for the cs5361, part number cdb5361 would fit your requirements. Note this is a 24/192khz capable chip, it can be forced to lower sample rates. There are also better performing chips, and lesser chips in the crystal semi conductors range.

data sheet for the eval board:

I've waded through the crystal site and found your local crystal distributor, if the distributor ask why you want the board, "i want to make an adc" don't mention you are wanting to make a cheap adc for personal use. They want to see sales potential.