Just got the Little Dot mk2 and hd600 and completed such a great dual set up! HD660s and HD600 with Topping DX7s DAC and Little Dot MK2. I feel like I've always been in the small majority that has thought the 660s was the superior headphone in the HD6-- line up, but now I understand. The 660s will stay my go to for gaming and everything else, but the 600 with that amp is amazing.
The HD660s and the topping DX7s is just a monsterous detail machine. Everything is so clean and precise. Amazing for gaming with how pin point the imaging is. It's scary because it's also good for monitoring microphones and that's a whole 'nother rabbithole im scared to throw money at.
The HD600 and MK2 is just wow. This combo is an experience that's just makes listening to music such a fun pastime. The pairing feels like 3D glasses for music that's just so special. I feel like there's more separation between all the sounds and they all have rounded edges giving it a 3D effect. Not sure if im explaining it right but it's so good.
That's a tough question. But all Honesty, I've sold both, and missed the 660s way more.I rebought it faster. The only reason I have the hd600 was because I found it for an incredible price