Champion_HDI mean better than what other amp. The Little Dot certainly sounds better than my Schiit Fulla 2 or NuForce Icon HDP when playing the HD6xx's, but my Woo WA3 sounds better than the Little Dot. The 300 ohm Sennheisers like the HD6XX really like OTL type tube amps like the Little Dot MK II and it's a great place to start. The HD6XX also scale really well as your gear improves.
OCBobI was going to get the fulla 2 but my 6xx were more then loud enough and a bunch of people told me it wouldn’t make a difference. They will just get loude. But like I only put mine at 60%and it’s still really loud on my pc alone
Champion_HDIt's not just about volume. A good amp can open up the sound, provide more power across the full audio spectrum making the headphones sound richer, wider, fuller. The right tubes can add a pleasing warmth to the sound that solid state amps have difficulty duplicating. I have used my HD6XX with several computers (none with a dedicated soundcard, however) and compared to how they sound on my Woo there is no comparison. Even my Little Dot MK II is better than any computer audio output I've ever heard. The Fulla 2 will work with these, but the Little Dot will work better. The Fulla 2 does make a good DAC/Preamp for the LIttle Dot.
Honestly, I don't think the majority of people who own the HD6XX have actually heard what they are truly capable of. Even with everything I've thrown at them, I'm sure there's gear out there that can make them sound even better.
Champion_HDThat's up to you, but for a desktop setup I'd go with the Little Dot MK II and then add some Russian Tubes. I don't think I'd do the tube upgrade that MD is offering. Better to get upgrade tubes on eBay. If I was interested in portability I might be more interested in the Fulla 2, but the Fulla 2 might not sound better than your laptop's headphone out.
2x Russian 6H6P-I Power Tubes Little Dot Amp Mk II 6N6 from the yenaudiostore: A good power tube (the big tubes) and better than the factory set. I suggest yen audio because its an easy place to start, but you can find the same thing from tons of different sellers. I like yen because they are reliable. If anyone else has tube seller recommendations I would like to hear them.
2x Voshkod 6ZH1P-EV Matched Pair Little Dot Amp from the yenaudiostore: My favorite signal tube (small tubes) for the Little Dot MK II.
Matched Pair NOS/NIB Mullard 5654/6AK5 BLACK HOLE plate tubes - Little Dot: Also a great signal tube.
This would be a good place to start, and with these signal tubes you don't need to change the jumpers since they are both in the EF95 Family. Here is a link to a fantastic tube rolling guide for the Little Dots. It's been a great reference and I've tried quite a few of the tubes (I've stayed in the EF95 Family)
https://www.head-fi.org/threads/little-dot-tube-amps-vacuum-tube-rolling-guide.563884/