Is Singlepower still in bussiness?

Yes, Singlepower ended in disaster, but my Extreme was the best sounding headphone amp I have ever owned. Unfortunately, Mikhail Rotenberg was started running a Ponzi scheme as his business went downhill. As with any Ponzi scheme, the biggest victims are the ones who got in last and they are the ones who are angriest.

But there are many Singlepower owners who have had their amps checked out by a qualified tech. Those amps can be purchased for cents on the dollar relative to what other tube headphone amp manufacturers are charging. And they sound extremely good.

A lot of electronics guy who made good stuff were terrible at the business side: look at Threshold, Carver, Mark Levinson.. Arni Nudell... these guys were great designers, and bad businessmen.

Nope, SinglePower finally went down for good. Finally. There are of course those of us who know a thing or two around amps and are able to repair the units still out there. I would not recommend buying a "stock" unit that wasn't inspected and repaired, but the modified ones sound pretty nice.