PrimaLuna Prologue Premium vs Luxman SQ-N10 ?

I'm currently selling a PL Prologue Premium. The unit I have has low level hum. When I received from former dealer in New York (who swears he tried it "with every speaker in my shop and it didn't hum") I noticed the hum but thought it normal for mid-level tube equipment. So be sure to listen for hum in your unit.

I used the PL Prologue Premium with KEF dynamic speakers and high efficiency Klipsch La Scallas. The hum is there in both cases although more pronounced with the Klipsch. The hum (60 hz I’m guessing) is constant, in both channels, and does not vary with volume or electrical circuit (yes, I've tried a cheater plug). It occurs on all inputs. If I had to guess, I’d say that some shielding was omitted during assembly. I’m planning to send to Upscale Audio for evaluation (unit is under warranty). I’ve heard from multiple PL owners who claim their units are dead quiet. I hope this is a fixable fluke.

"The hum (60 hz I’m guessing) is constant, in both channels, and does not vary with volume or electrical circuit (yes, I've tried a cheater plug)."

Playing through my Thiel 2.4se, I thought the bass was outstanding. Deep punchy and full. This from speakers not known for their bass output. The midrange was primo, as one would expect, but the treble was strained. BTW, have you checked for any hum from the PL? As I type I'm listening to the PL connected to my KEF Ref 201. I still hear some electronic artifacts -a "buzz" from the mid/tweet and 60hz hum from the woofer. These are VERY low-level and can't be heard unless ear inches away from drivers. If you have normal hearing and your unit is stone silent inches away, well, God bless you...  

Really, the artifacts are so low (with the KEF REF 201) I don't think there is a problem. But I'll keep the outlets in mind! Note: I was using the PL with Klipsch La Scalla speakers (105 db efficient). Hum was MUCH more pronounced. A pity as the Klipsch is WHY I purchased the Prima Luna.