Post date: 30-Apr-2011 23:23:58
I have just been made aware of a product that will provide a relatively clean (average <1mV noise) 5V external supply on the USB cable. It is a linear 5V/1A external PS that links into a USB cable ( http://www.aqvox.de/usb-power_en.html). On the purchase page (http://www.aqvox.de/bestellung.html) they even state that it is suitable for the Hiface - maybe been looking in on the modifications mentioned here. Cost is €89 + shipping.
An owner of a MK1 (Tom Bubulya, Ph.D.) just emailed this to me about the AQVX supply above (reprinted with his permission):
Man, another good suggestion!!! The improvement using the external power supply is not subtle. The finer details are better defined but the most marked changes are with imaging (even more precise), soundstaging (very layered and deep) and lower octave authority. One other thing that I noticed when listening through my HD800's, the image location has shifted so that the performers are more at eye level then forehead level. It is hard to believe the improvement considering how good the MK1 performed in these areas. Bypassing the 5V usb to the hiface is, in my opinion, necessary and not just a tweak.
An even cheaper ($30) & possibly cleaner option (40uV noise) is to be found here but it is a kit I think & may require some soldering?
Looks like these powered hubs will also work & are cheaper again ($14) but you need to provide a 5V PS http://www.newegg.com/Product/Product.aspx?Item=N82E16817731002 http://www.newegg.com/Product/Product.aspx?Item=N82E16817402014
Or this one which seems to be the cheapest yet ($3) http://www.streakwave.com/Itemdesc.asp?ic=5VUSB Again supply your own 5V supply