I just read this article regarding current source amps: http://www.innerfidelity.com/content/first-look-current-source-amp-performance#IsVXxe52yf8J01th.97 Are Audio GD amps current source? I just got an HD800s and was looking at ADG, but I may have to rethink it if this is true.

Does such an amp exist for around $1000?  If it has a DAC, that's fine, but otherwise I can use my Teac UDH01.  This will be to run my Sennheiser HD800s.  I prefer a solid state, but I'll consider a tube amp if it doesn't completely break the bank.   Thanks for your help!