You can achieve playback of 96k files (Stop the Clicking buffer over/under runs) but not 88k with the HRT MicoStreamer. This can be done by raising the numeric feedback value for the affected sample rate. I did this yesterday after comunicating with an HRT product specialist a few times and it works.
A, MicroStreamer should have V1.3 this eliminates the need for a USB hub (see Support at HRT Website to do this)
B, You need a PC.
C, Download "Upstream" from this link https://www.dropbox.com/s/sittlatrvipgdbu/UpStream.exe
D, Follow theses instruction
There will be three value settings one for 32/48/96 KHZ another for 44.1 KHZ and another for 88.2KHZ
Setting Device Feedback characteristics using the UpStream utility
1) Launch the UpStream utility and connect the HRT Microstreamer to computer via USB
2) Click on the FEEDBACK tab and click retrieve. This retrieves the set values.Write the numbers down in case you want to reset them. My 32k 48k 96 value read 0.03125
3) For the 32k 48k 96k sample rates click on the pull down (down arrow) next to the sample rate group and select 0.25 this worked for me.
4) Select the new resolution value for the sample rate and program the device by pressing the PROG button.
When you have made changes to the feedback value for the sample rate you wish to change and have programmed them to the Streamer, you may exit the UpStream utility by pressing the red X in upper right hand corner of the utility.
(most of the above was copied from my HRT communications)
44.1k we all know works so leave it.
For 88.2k I tried all the values could not get the clicking to stop.
Tried to upload screen shots but the forum wouldn't let me. This is my first post on the forum. I'm running a 64Gig iPhone 5S iOS 7.0.3>CCK>USB A to USB mini> HRT Microstreamer>custom Westone AC2s or HiFiMan He-300s. I'm playing 44.1 and 96 KHZ FLAC files with the HRT MicroStreamer. I don't know if 48 KHZ FLAC will play because I don't own any. New to the Forum but not an audio newbie.