DAC for iMac System

Try and find a Music Hall 25.2 used. I have the .3 and am loving it and I have a very revealing system.

Geek.
iFi Audio iDAC

Take a look at Schiit product - I have the bifrost and it is excellent with the optional UBER analogue upgrade.

They also have the Modi DAC for $99 and the Loki, a DSD processor for $150.

They make some very good product

The HRT music streamer II can be found for under $100 used. Goo as a starter allowing you to explor the DAC market. Alot of good $3-500 DACs available which will be offered on the future used market.

+1 Williewonka. The bitfrost is a good DAC but with USB may cost more than $300 used. Have not heard the Modi but would be tempted to try one as a starter DAC.

The iFi DAC recommendation is sound (no pun) and within budget new.

One additional thought, if you get a DAC with a coaxial input in addition to the USB, you can upgrade your digital source with use of a USB/SPDIF converter at a later date.

Good luck, let us know what you find.