Simple question, best sounding inexpensive DAC.

HRT MusicStreamer 2+ and Micromega MyDac are 2 good choices.

Micromega MyDac is cheap and very good.

Define "inexpensive." One man's ceiling is another man's floor. In any case, a used Benchmark DAC1 is a bargain at around $500.

Like your reasoning, love the Magnum Dynalab receiver and think your amp/speaker combo will benefit from a dac upgrade. So, I am a big fan of the Eastern Electric sabre chip dacs with lots of inputs, ss or tube (12AU7) output, phase button too, best buy/used for $500. For a bit more, $600, the Metrum Octave is hard to beat IMO. Next stop would be around $1000 for only slightly more, "full sounding", with an Audio Note 2.1. as my choice there but requiring a SPDIF. YMMV.

Whatjd hi.
Seeing your using a Denon changer, you'll just be playing Redbook CD's.
The Schitt Bifrost Multibit would be a great choice as this uses a proper Multibit dac chip, it is the "Bit Perfect" way of conversion of Redbook cd (PCM)

Schitt is owned by Mike Moffet who was head owner/designer for Theta digital, and we all know what he did there.
Now he owns this small budget company Schitt, and making big waves buy bringing Hiend technology in not so glitzy cases to the masses.

PS:Always choose the Multibit option for Redbook CD if you consider any of the other dacs of his.

Cheers George