Tubegroover...I have heard David Bernings zh270 driving my aged quad 63s, alittle while ago...My goodness. Mick Maloney and David Berning certainly have alot in common... Design build, direct sales, extraordinary performance and value in their electronics.Wading through the discussion forums the past few months in audiogon, I have gained a new perspective on this thrilling hobby...More so then what i have gotten out of any other source in the past.Finally,I would like to thank all on this thread for their endeavor and expense in finding ways of enhancement...Tubegroover and Slowhand, look into borrowing a shunyata tiapan a.c.cord to try in your Berning amps...