I heard them with Dared mono block tube amps yesterday and the 40 watt Nad 316BB. To be honest they were congested with the Dared amps. I thought the sound stage shrunk and sounded better on the NAD IMO. The Leben is 18W and should be a good match. I will say this on the NAD I liked the sound of the HE6 and look forward to my loaner audition
How did you and Ross find the comfort of the HE-6s? Where they heavy, clamped?