Hi,   Just posting comments on a set of tubes.  I have the Bifrost uber+Lyr2 and HD650's.  About 2 months now.   Stock tubes were fine but wanted to try something, anything better  : )   So I ordered from tctubes after getting a quick email back on a question on the matched pairs:  ...

I got the Lyr2 a month ago and used it with Grado 80 and Sennheiser HD558, worked great.  I recently got the HD650 from focuscamera, they had a deal for $299.    The 650 are my first good headphones, so I think they sound great  : )     I've listened to blues, rock, folk...all sound really...

I have one running on a asus eee netbook, running jriver and win7.  CPU never maxes out and jriver has a large buffer, so no noise/stutters at all.   No noise from unit.   Works great, small enough, and I like that it's just usb powered, easy to move around and play through rca jacks also...