I immediately fell in love with the sound of the Herus. The ESS chip delivers a very clear and (micro)detailed sound with a wide and deep sound stage. The DAC is neutral but not in an analytical way, it just shows you everything there is in your source files and it does that without going to the over-analyzing side. It stays musical and delivers the music with a superb air and with the right amount of space between the instruments. I’m very impressed and I honestly can’t say one bad word about the DAC part, this is how a DAC is supposed to sound for me. I have heard a lot of bigger and more expensive DACs that didn’t get to this level of sound reproduction, call me a fan.
The Herus also plays DSD/DXD and after I configured my Foobar2000 accordingly, I listened to some DSD64 files from The Dire Straits, Pink Floyd and Michael Jackson (DSD and PCM). Overall you get a smoother more relaxed sound with even more micro details and great resolution. Unlike Dave, I’m convinced of the DSD sound quality but I won’t be switching my whole collection to DSD immediately.
Back to the unit. So like I said, I wasn’t too impressed with the Sennheiser HD650 straight out of the Herus but hearing how good it sounded as a DAC it just had to sound better than what I was hearing. I took it home with me and locked myself up in my listening room for a few hours where I actually tried every single headphone in my collection from the IEMS to the LCD-2, straight from the headphone jack itself. Long story short, I find the Herus to sound great with the majority of headphones and even the planar technology ones. What a surprise! The problem for me lays with the higher impedance headphones like the 300Ohm Sennheisers and the 250Ohm Beyerdynamics. For some reason they in my opinion just don’t seem to get what they need to sound the way they are supposed to. All the other headphones sounded really great though, from the portable HD25 and T51p to the mid class Beyerdynamic COP and DT770. Even the high class Hifiman HE-500 and Audez’e LCD-2 sounded very convincing and enjoyable; I did not see that coming when I first plugged in the Sennheiser HD650. Unfortunately I had to send the Hifiman HE-560 sample back before I got a chance to try it with the Herus. Hifiman is working hard to get the improved samples out and I hope to try it soon with this device. I did try it briefly with my custom IEMs but I have 2 (minor) issues with it. First of all it plays loud so you have to set the volume extremely low to be able to listen to it. Second, there is a bit of noise audible when volume is at 0%, my IEMs slightly hiss but fortunately you can only hear it when the music is off and when there are silent passages in the song.
I would describe the general sound as linear, there is no focus on bass or treble. Maybe vocals just are a bit more forward but you get a nice detailed and airy sound with just the right amount of everything. A true high level sound.
The Other Players
There are a lot of competitors on the market when it comes to portable USB powered DAC/Amp boxes and it is impossible to cover them all. The Fiio E10, an old fav of the site, is more or less the same size but the E10 is getting “old” and technically the Herus easily beats it. It sounds a lot better too. Same goes for the tiny Stoner Accoustics DAC and all the other devices. I would put the Herus closer to the level of the CypherLabs Theorem for the DAC level (Amp wise it can’t compete just yet). It’s that good.
In the end this Resonessence Labs device is an absolute winner. It’s well made, looks good and sounds fabulous. It’s so small you can take it with you anywhere and as it is USB powered you can use it at all time. It works with your iDevices and Android phones and it is upgradeable. High impedance headphones however aren’t the best match when using the internal amp. When using the Herus at home I would certainly use it in combination with one of my desktop amps but on the go just use the internal amp and enjoy! Resonessence did an excellent job and I’m secretly jealous that Dave is getting their Concero HD for review.