HiFiMan EF2 on Win 7 X64 Pro, issues!!

Hi there forum,

Just bought a pair of ultrasone Pro900s and a HiFiMan EF2 amp.

Swapped out the tube for some better ones, plugged in iPhone through the RCA, and all sounds fantastic.

However swapped the source to my laptop running win 7 x64 and the amp is not recognized!? Has anyone else had this problem?

I read somewhere that this might be due to the fact I'm running a 64bit system and the DAC is only 32bit compatible!? But surely not!!!

Has anyone else had this problem? If so, what to do!?

I had noticed online that there is also a HiFiMan EF2A now available? But I'm not sure what the difference is....probably x64 compatible right???? Would be just my luck!!!

Well if any can help I would really appreciate it!

After a bit of digging around on the web it appears as if it is simply a driver issue i.e. Support for 32 and 64 bit operating systems.

Both the HiFiMan EF2 and EF2A have the same DAC, the Burr-Brown PCM2702. This DAC only (as far as I can see so far).

The only difference between the EF2 and EF2A is a slightly increased output and USB volume. But as far as I can see, both units will still be 32bit only. I will keep digging.