DAC upgrade

Hi, My digital system currently consists of a Logitech squeezebox touch (Jerome PSU upgrade, software mods) into a Music Hall DAC 25.2 (Tube & output cap upgrade), Marantz PM-15S2 integrated amp, and DIY Seas Thor speakers, all cabled with blue jeans cables. The PSU to the touch was an immense upgrade in terms of resolution, as was the output caps to the music hall dac, but I'm still looking for more resolution.

This was my first DAC, and kind of stands out as being the "weak link" in my system. Does this sound right? What is audiogon's thoughts on upgrading to a better DAC? How much should I spend? Or should I not bother switching DACs, and upgrade the MH unit further? Or... am I overlooking something else?

P.S. My analog front end sounds very good to me, but I don't have nearly as much vinyl as music files.

Thanks for any recommendations