Don Sachs DS2 vs Wells Audio Commander

i put shuguang we6sn7’s in the 2 primary signal (left) positions - at don’s recommendation ... and old stock rca red base 5692 in the minor driver positions

https://www.china-hifi-audio.com/en/shuguang-electronic-tube-valve-c-49/shuguang-we6sn7-electron-tub...

i have a gaggle of 6sn7-equivalent old stock tubes from my days with vac and cary amps, chose the quietest ones i had

i did go through 3 pair of those lovely big bottle chinese tubes to find a very quiet set

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.