I was fortunate enough to hear the amp with several headphones, and also got the chance to chat with Michael Zähl at length. I got the feeling we could talk for hours about the science and engineering aspects of the audio world, and even though I know much of it would’ve gone over my head, he was super friendly, and it was great to get his insight. You got the feeling he takes this stuff very seriously, and that an extreme amount of thought and careful consideration goes into his designs.
For the HM1 it felt like his focus was to achieve the best possible sound in a device, along with features that would be actually used and valued by the community. I think for all the devices that have features like widening effects they often come off as gimmicks - even on otherwise excellent devices. That was not the case here.
To give a bit of context, many will know that I’m someone who really doesn’t get that much into the whole source equipment world, as I’m much more focused on the headphones and I find that in the majority of cases, it’s all fairly similar. While I do find there to be differences, I usually don’t find them significant enough to mention, and there’s already lots of great sounding inexpensive equipment out there with enough power to drive the majority of headphones. So, why comment on this one?
There’s a reason why every person I talked to at the show confidently referenced the Zähl HM1 as the best headphone amplifier they’d heard - at least for the solid state stuff - and it’s because it actually was a step above, and made the headphones I listened to off of it meaningfully better sounding than I was used to. If anyone has watched my live streams on the subject of source equipment, those are not comments I’m going to make lightly.
Of course, I’d need to spend more time with it, do ABX comparisons and all of those things to get a more comprehensive understanding of the device, but strictly for what I listened to, over the course of that particular session, it was the best I’d heard the following headphones sound:
- DCA Stealth
- DCA Aeon 2 Noire
- Abyss Diana TC
Now I’d only heard the Diana TC off of some of the Feliks Audio gear across the floor, but I did also prefer it off the HM1. But with that said, I’ve spent quite a bit of time with the two other headphones previously and am well acquainted with how they sound off of a wide variety of equipment. Notably these are all planars, so it would be interesting to try some dynamic driver headphones as well.
In any case, with the two DCAs, they mainly sounded like they had more depth to them - like in a kind of sense where in a subjective assessment I’d find them to be more ‘detailed’ sounding - but also that the sounds had an extra kind of structure to them, for whatever that means. So, overall just more engaging than what I was used to with them.
A number of other listeners who I was with also commented on those headphones sounding more punchy, impactful and ‘dynamic’ as well, although I wasn’t specifically indexing for this quality during that session. Those who didn’t like the Stealth, for example, liked it a lot better off the HM1, and the same goes for the Noire. So let’s just say the ‘technicalities’ of each headphone shone through on another level.
Then there are the functions, the most interesting of which is the widening effect. In other devices, like the Pro iCAN there are functions with similar intentions. While these types of functions in other devices can be useful to a certain degree, the HM1’s implementation felt more nuanced and calculated.
Importantly it felt more realistic than any other I’ve heard for that effect. It was subtle - not like changing a DAC filter subtle, more like 20% widening effect to the whole presentation if I had to put a number on it. So still significant enough to where you could easily tell.
Lastly, there’s also the mains adapter power unit. Michael discussed this briefly in an interview we did with him so make sure to check that out when we release it in the coming days to get more info on the intention behind that design, as well as its functions.
In any case, this is truly an endgame piece of equipment, and I need to get one into the studio and do a lot more testing and listening to it to get the full picture before giving a verdict or anything like that. But I am going to say that if you don’t think amps make a difference… (which is something that would be understandable given that many of them don’t really sound all that much different) you need to listen to this, and take any opportunity to hear one if you can.