Up for your consideration is a Bryston BUC-1 USB Converter.

I used this for a few months to convert the the USB output of my Mac mini to the coax input of my previous DAC - integrated DAC card in Bryston BP-17^3 preamp. But, I have since upgraded my DAC and no longer use it.

Like all things Bryston, this little box is built like a tank and it is quite heave for the size!

This is a discontinued Bryston product so information on the web is a bit hard to find but here is a link to the video Bryston posted on their youtube channel introducing the BUC-1:

I bought this as a NOS unit. It comes in the original box, with the manual, the original Bryston branded USB "key" drive with Windows drivers (see photo) - Mac does not need any. No power cord is included as there was no power cord in the box when I received it.

Asking $450 OBO - Price includes USPS Priority shipping CONUS, tracked, insured, and PayPal fees.

Thank you.

Features of the BUC-1: (from the Manual)
• USB Audio Class 2 input (192KHz/24Bit asynchronous)
• USB drivers supplied on flash memory (thumb drive)
• Linear power supply
• Sample rates: 44.1KHz, 48KHz, 88.2KHz, 96KHz, 176.4KHz, 192KHz
• Transformer coupled SPDIF and AES/EBU Digital outputs.
• SPDIF Output (via CoAxial RCA/phono jack and BNC connector)
• Remote On/Off Control Trigger input, 12 Volt
• Compatible with CD Drives, Sound Cards, Computers, Music Servers.
• Cosmetically matches C-Series BP26, MPS2, etc

Here are several photos: