DACs that upsample to DSD internally?

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

yes - iPurifier is one solution - if the dac uses power from the USB cable.

regards

Xrayz - regarding cables - I'm not going to tell you that cables ARE your problem. but I've found that with really good cables, even the most affordable component can perform to a very high level.

Having said that, my experience with the Bifrost DAC is as follows
- I purchased the original Bifrost with the USB port and UBER analogue output stage upgrade
- I then installed the newer USB port upgrade - but I was still left wanting more
- I  invested in the Musical Fidelity V-Link 192. This proved to be an exceptional purchase and really proved that not all USB interfaces are anywhere near equal - this provided a significant improvement to the really fine details.
- Lastly I upgraded the Bifrost to the 4490 upgrade option which provided a significant improvement in fine details

In parallel with that I started investing in really good cables

For USB cables that linked the computer to the V-Link192 I settled on a cable that had a separate power cable like this one and found it improved the details even more when powered with a separate power supply
http://www.ebay.com/itm/Power-supply-and-USB-cable-separate-audio-signal-cable-/251589388236

The power a cable for the DAC is a DIY cable that I developed...
http://www.image99.net/blog/files/be8de0c383c5434907610d6b55049e69-75.html

For IC's I started with the KLE Innovations gZero3 and ended up with the gZero20 - a cable which costs almost three times what I paid for the DAC + Upgrades.

However, I now use a DIY IC cable that I developed...
http://www.image99.net/blog/files/4127b5fe2694586e383104364360373b-74.html

Crazy you say? - certifiable in many peoples eyes -  but I no longer yearn to replace my DAC and the sound really is excellent.

The DAC you have looks very capable and I think it would benefit greatly from some cable upgrades - but rather than experiment as I did, I would recommend taking the DAC to a good audio store that sells high-end cables and get them to connect it to one of their systems - I'm sure that the prospect of selling you some high-end cables they will jump at the chance and you get to see how the DAC performs outside of your system

If you are in the Toronto region let me know - I might be able to arrange an audition of my DIY cables :-)

Regards...

Xrayz - One last thought - what software are you using to stream?

I use iTunes for Library Management (only), but I use Audirvana to actually stream the data in the file to the DAC.

Audirvana bypasses all of the apple code that is normally used for streaming - WHY? - because Apple actually messes with the data file before sending it across the USB link and Audirvana has an option to send just the raw data.

Using Audirvana improved the fidelity and details considerably, but you have to set it up correctly - the user manual is very good.

Audirvana will also play DSD files (so I'm told) by converting them in real time on the computer - NOT in the DAC.

Audirvana also caches the entire track in memory before it starts to play, so there are no delays in playback waiting on network and hard disk processing - just straight down the USB pipe!

Regards...