Don Sachs DS2 vs Wells Audio Commander

All I can tell you is my Don Sachs pre (about 9 months old now) has bested my AR-6-SE and my PSA-BK pre's.  I couldn't be happier. 

No hum from my DS either (94db speakers with accuton drivers). Sounds like maybe you need to do some troubleshooting. Maybe you've got a small ground loop issue in the system? That's the only time I've heard hum out of my unit. 

If you have to put your ear up against a speaker to hear tube noise then you don't have a problem.  Dead silence in that situation equals SS and good SS at that.