The Teac UD-501 appears to be an amazingly well received DAC in the Head-fi/HF community.  Seemingly often by folk with only entry level DAC experience.  It is often championed as the new bang/buck performance king or very near to it in its relative price bracket.  It is well known that myself and Purrin are hardly fans of this device despite its current accolades.  I know it's hard to fathom the discrepancy for some.  So I offer some anecdotal evidence of other Teac UD-501s out in the wild belonging to some well respected folk in the audio industry.  We always suggest people hear for themselves.  However, to the people that already have, we would like to say a picture is worth a thousand words.  Two in this case.

Mike Moffat is considered one of, if not the father of the DAC.  Here is how he utilizes the venerable UD-501:



Craig Uthus is a well respected amp and speaker designer know for his superb SET offerings derived from years of experience at UREI (http://en.wikipedia.org/wiki/Universal_Audio) and later JBL.



Neither are plugged in, let alone playing music.  This is all either purely coincidental or conspiratorial depending on your PoV.