Close to a decade ago, I purchased a Benchmark DAC1 USB which continues to sound very nice to me. I've been using the DAC with my iMAC, as a headphone amplifier, and sometimes with my Oppo universal player. I have no plans to upgrade the rest of my system since it is exactly where I want it to be. Recently, I've been wondering if it would make sense (in terms of $$ and improved sound quality) to upgrade to a new DAC and, if so, what should I purchase and why? Thanks for your input!