First impressions:
All comparisons are against the only hp amp I've used, a Beyerdynamic A1 clone (HLLY RMK5), that's only quoted at producing 170mw max. Undoubtedly not enough power for my planar headphones. The only phones I'm currently using are the Audeze LCD2 fazor.
Firstly, I guess I'll mention the dip (gain) setting. To begin with I used the 'thread default' setting of +6. I read (here) many recommendations that this is probably the best position (for planar phones). In the +6 position I found that most of my listening was with the volume set no higher that the '9.30' position, and usually lower (in the range of the indention in the face plate). I'll do more experimentation, in the future, but I thought that this seems a bit low in the usable range, so I've reset the dip to the all down '0' position, This has meant that volume is now using the '8.30' to '10 o'clock' range, so far.
I don't know if it's the size of the volume knob, but the adjust seems very fine; it takes some considerable turning movement to effect the desired change. This is a good thing; fine adjustments (small increments), in the volume level, are easily accomplished.
The sound-
Some positives:
I've already mentioned the power difference between the H10 and my other amp; at 2.7 watts, the H10 is getting on for 20x as powerful as the Beyer. I'm not suggesting that power is an all-encompassing factor. Just that any amplifier needs to be up to the task that it's set; it needs to match well with the transducers it's connected to. Some transducers require more power, to have the necessary reserves and control, than others. In the headphone world, planar headphones (and a few others), are notorious for needing 4 figure milliwatt power outputs to get the best out of them, regardless of other factors.
So, with this in mind, I was quite glad to get the immediate impression that there is better bass reproduction, with the H10. Bass is the most power dependent part of the frequency range; it takes more energy to get the drivers to 'shift the air', to produce a bass note, and to control the driver once it is moving. The H10 seems to be doing this, better. The bass has more visceral impact, a little more extension, less mid and upper warmth and more transient impact. Previously, I'd found the LCD2f bass to be just ever so slightly warm and lacking 'kick', especially when compared to the he400. They definitely seem to have found a little of that extension, that I've been looking for. But I'm sure that there's still plenty more to be found!
Some not so positives:
I'm not panicking yet; it's only got about 3-4 hours of running; many posters have said that the H10 needs 10x that, to start showing it's true character.
The second thing I noticed was that the sound is a little......'tinny'. It's still full and weighty, as I've mentioned. But regarding the mid-range and treble, the treble just isn't quite right; sometimes something, a bit of percussion, sounds very 'there', very present, and then other, perhaps higher frequencies, sound very recessed and unresolved. And vocals are showing some exaggerated 'C' and 'T' tendencies (or should I write 'TTendencies'). I guess it's (currently) slightly emphasising perhaps the 10Khz region (I'm just guessing.)
Maybe it's this treble emphasis that's having the effect of upsetting the treble mid-range balance; the mids aren't quite as present as I'm used to; I'm not regularly having the "OMG; that sounds soooo real!!!" moments, that I'm used to. In fact, this combination of unruly treble and recessed mids is making my LCD2 sound a little reminsent of the he400, that I got rid of!
But as I say, it's not time to panic; I'm very much a 'believer' ("I belieeeeevvvve!!!") in burn-in, and the 3-4 hours of listening time is quickly turning into 8-9+ hours. As soon as I notice any change (apparently by around 40 hours, I should), I'll report back.