Resonessence Labs spill specifics on Herus+ DAC


The Resonessence Labs Herus has long been championed around these parts for its ability to play nice with iDevices, power thirstier headphones as well as pack full-size USB and 1/4″ headphone sockets. Few dingus DACs can manage all three – the Herus earns the price premium over competing units from AudioQuest, LH Labs and HRT. The HRT microStreamer is the only other DAC with sufficiently low power draw for an iPhone but it doesn’t command headphones with as much authority as the Herus. The LH Labs Geek Out 1000 is the only other DAC with enough raw grunt to properly juice MrSpeakers Mad Dog but it won’t talk turkey with iPads and iPhones.

At this year’s Rocky Mountain Audio Fest I tried – and failed – to report properly on the forthcoming spiced up version, the Herus+. With more information arriving by email from head Resonessence Labs dude Mark Mallinson, an opportunity to make amends now presents.

Likes its forerunner, the Herus+ uses a ESS 9010-2M chip to decode PCM streams up to 32bit/384kHz and DSD64/128. Output impedance has been held to 0.2 Ohms.

On the inside, ch-ch-changes: redesigned circuit board and a bump in onboard memory accommodate two new features, both of which can be activated via the chassis’ now raised logo – on the Herus+ it doubles as a button. A quick press switches the logo glow from blue to magenta and engages the first, in-house coded apodiziing filter. Press the logo button again to engage the minimum phase IIR filter. Press it a third time to return to the original vanilla filter.

According to Mallinson, “[these] filters exist in order to improve the audio experience of music recorded at the 44.1kHz and 48kHz data rates. They have little to no effect on DXD or DSD data sources.” If you’re a Redbook hound, good news. Less so if your DSD tail wags the DAC dog.


You might think that the extra power required to run this filter processing means a stronger power draw on the host device. Resonessence Labs’ Canadian development team have countered this potential problem with another slice of clever. A long press of the logo button kills its illumination and kicks the Herus+ into a low power draw mode, making it even more suited to iOS and Android decoding.

Whatever the connected device, the Herus+ receives volume control instruction from the host’s operating system; markers that correspond to points within the Herus+’s own 32bit range. Following customer feedback that control sensitivity was previously too crude, Resonessence Labs have implemented more granular attenuation in this new model; an improvement that will eventually be made available to existing Herus owners via a firmware update.

The Herus+’s fancier feature set comes at a price: US$425. That’s US$75 on top of the standard model.

Read more on how the two models compare technically here.

Pre-orders are now being taken for the Herus+ with free shipping in North America on all orders received prior to 21st November 2014.

Further information: Resonessence Labs

Written by John H. Darko

John lives in the NOW + HERE = NOWHERE. He derives an income from the ad revenues of DAR. John is also an occasional staff writer for Stereophile, 6moons and TONEAudio.

Twitter: DarkoAudio
Instagram: DarkoAudio
Facebook: DAR


Leave a Reply
  1. Great sounding DAC/amp. My son has a pair of inexpensive but very good Etymotic MC5 in-ears that have little use. I heard them a few years ago on good gear, but they never (to my aural recollection) sounded as good as when I play them with the Herus+. I haven’t played it enough to compare power saving vs non power mode, and the switchable filters are also a nice touch. The (first magenta) Apodizing filter is my favourite thus far with these in-ears. Next, is to try it in a room stereo system.