I owned the HD650 and ran them off of a Benchmark DAC2 HDR which has a pretty high power class A amp in it. The combination was pretty boring and lacked dynamics. The lack of dynamics is the biggest issue for a speaker guy. No headphone gets it right. Just something that comes with the territory. I have not heard the mass drop amp.
For me me personally I would take the Focals Elex on a mid priced amp over the HD650s (same as the HD6XX I believe). Some people run the hd650s on crazy expensive amps and they say it helps but it is just not for me. The focals get up and go even out of a phone (but need a better amp to pull out all the details and soundstage).
I just use a chord mojo and phone these days for my headphones. Desk top stuff sounds better I guess but not as much as you would think. Just depends on if you listen to the details or the music...
Do NOT buy the focal Elear. It is terrible! Worst headphone I have ever owned. It has a 25db dip in the upper mids and is super bassy. I hated it when I owned it. Oddly the Focal Elex is just the Elear with pads from the focal clear more or less and it sounds totally different. It is like putting your speakers in a very bad room then moving to a very good room.
For me me personally I would take the Focals Elex on a mid priced amp over the HD650s (same as the HD6XX I believe). Some people run the hd650s on crazy expensive amps and they say it helps but it is just not for me. The focals get up and go even out of a phone (but need a better amp to pull out all the details and soundstage).
I just use a chord mojo and phone these days for my headphones. Desk top stuff sounds better I guess but not as much as you would think. Just depends on if you listen to the details or the music...
Do NOT buy the focal Elear. It is terrible! Worst headphone I have ever owned. It has a 25db dip in the upper mids and is super bassy. I hated it when I owned it. Oddly the Focal Elex is just the Elear with pads from the focal clear more or less and it sounds totally different. It is like putting your speakers in a very bad room then moving to a very good room.