Mine is dead silent with everything, curiously except HD 580, for which the pot is a little noisy in some positions. Quite odd.

I can't say if the amp is more powerful, it's not obvious, but the level of gain is about the same.

I think many people would find the difference not enough to justify the swap. It's worth it to me, definitely, but I think it's such that nobody can guarantee that you'll feel the same. Fortunately it's not a terribly expensive experiment to see if it's worth it to you.

Compared to my DX90, Z1 has slightly more mid presence and is less liquid in sound. the HA gets it closer to the DX90 than stock, but still leaving the Z1 as its own thing. I do value the mid presence of the Z1. I can see how others might not. I'm not sure if Z2 has the same mid present tendency...

Yes, with stock amp, but discernible with a couple of other amp options in place too (LME49720HA and NA). A small but clear edge for the DAC on the Z2 I'd guess, unless it's the way the amp is implemented apart from the chip used.

What I think I hear is that the Z2 offers a clearer picture on detail than the Z1. Listening to classical orchestral music, a small percussive sound in the background is likely to be more cohesively placed on the Z2, and so far, that holds regardless of the opamp used in the Z1. And all those...

No problem with my mac, works the same as Z1.

First impressions, in stock form, are promising compared to Z1 with LME49720HA. I'll say more once I've worked out what exactly is going on in the difference.

I got my Z2 this morning. To confirm, yes the firmware update is exactly that - unpack the bin file and put it in on your card, put it in the player, when you turn the player on the blue light flashes quickly, and then you turn it off and remove, and with the DAC left is now left and right is...

After being bounced around post office sorting centres, it seems mine is finally going to arrive this morning - I'll let you know.

I'm waiting on delivery still. I suppose the firmware installation is the same procedure as for Z1, which is straightforward.

My Z2 is due for delivery hopefully today, if not tomorrow. I believe there is a firmware update already, supposedly it was distributed via Zishan's Taobao page. I wonder if anyone can find it? I can't. Edit: I found it...

Not even a soldering iron unless you want to solder it onto a dip8 adaptor (would make inserting it into the socket even easier), since the socket on the Z1 is just a plug and play socket - no soldering involved.

The stock opamp is not bad at all, nothing to complain about. It is possible to do worse than it in various particular regards. For instance I found one of the opamps (sorry, I don't remember which) to offer striking detail in a way that rendered everything unlistenably incohesive - perhaps it's...