DACs that upsample to DSD internally?

Format conversion is probably the most accurate terminology.  I'm not sure that converting to DSD will give you more detail.  If anything my Esoteric when used in that manner sounds smooth, actually very smooth.

How did you come to the conclusion that your DAC was the cause of the lack of detail?

What DAC are you using?
How is it connected to the digital source?
What cables are you using, i.e. interconnect and power.

I stream from my iMac, using a good USB cable, into a musical fidelity USB TO SPDIF converter, into a Bifrost DAC.

It sounds almost as agood as my analogue rig.

I play all formats (except DSD) and sample rates up to 24/192

I would suspect your problem may not be the file format

Regards

The one I'm using now is a no name one built from a very inexpensive assembled kit that I bought on here some years ago. I got it for using when I was "in between" DACs. (I would sell one then buy another to upgrade) My last one was a Metrum Octave, but even that didn't have very much detail. I'm not sure which to buy now, but I thought I'd go in the totally opposite direction and try DSD. In any case, my current DAC is by far the weakest link in my system.

@williewonka 

My cables do need upgrading also, I have Cullen power cords, a Morrow IC, and usb and digital cords are just from Blue Jean. I recently had dedicated power lines installed. I thought I'd try to find a good DAC before upgrading the cables.

I have the Mytek Manhatten (I).. It converts everything into DSD