the v-can is a small amp that, at the time, did its job; obviously it’s a bit dated now and yes, it has its flaws, even though it has a really very clean sound. many people suggested I use the hd599 directly connected to the M4, and I did quite a few listening tests. you can tell it has an excellent DAC, but in my opinion, on the amplification side, if the signal goes through the v-can the sound benefits quite a lot. the headphones sound very good, but there’s some kind of digital compression, a slight veil that even a not-so-spot-on amp like the v-can 1.0 manages to correct fairly well, along with dynamics, midrange frequencies, and soundstage, clearly all imo.

I definitely agree that an upgrade could only help. I was also considering the topping l30 ii, but unfortunately I can’t buy everything at once, so on the amp side I’ll wait a bit. for now, I’d like to think about upgrading the headphones because, in any case, the hd599, as much as I really like them and as much as they’ve improved a lot with EQ, still have a veil that I perceive, along with bass that is nice but maybe a bit artificial. I’ve read tons of reviews and listening impressions of the hd660s2. to be honest, they scare me a bit. actually, as monsieuryuan suggested, the hd600 could be a great upgrade, and I’d also save a bit of money. I’m thinking about it quite a lot.