I've listed my NuForce U192S converter for sale on eBay. Here's the link https://rover.ebay.com/rover/0/e1200...&sojTags=bu=bu
Up to 24 - 192 KHz. Small, light weight, and powered by the USB connection.
This was my solution to go from an iPhone streaming flac files via USB to a DSP with optical input. It works great - stable, quiet, totally trouble free. I'm selling it because I upgraded my DSP (has its own USB audio input) so I don't need to convert anymore.
I tried other solutions too - Peachtree Audio X-1. The NuForce worked and sounded much better. Also tried using HDMI. To me HDMI's SQ sucked.
If your DSP or DAC has an optical or coax input this converter will give you a big improvement in SQ for not alot of $$.