• Herus
  • Herus


Resonessence Labs HERUS: Asynchronous USB Audio 2.0, 24bit 352.8Ks/S, DXD and DSD64/128, 2.4VRMS Headphone DAC

HERUS is the smallest form-factor, audiophile quality USB to Headphone DAC. It uses the USB Audio 2.0 Asynchronous protocol and supports DSD64 and DSD128 as well as high data rate PCM at 24bits up to 352.8Ks/S. It is a USB powered device that achieves more than 100dB of SNR, (typically 108dB) and is capable of driving 2.4V RMS, (ie 6.8V pk-to-pk) into headphones from 600 Ohms to 32 Ohms. The distortion in all cases is better than 0.005% (85dB): the measured THD+N is typically 89dB for 32 Ohms and 90dB (about 0.003%) for 600 Ohms.

HERUS is designed to operate with MS Windows, MAC OS and Linux. You may download our Thesycon USB Audio 2.0 driver to enable USB Audio 2.0 on Windows. HERUS uses the ESS 9010-2M DAC, our custom code, and our own asynchronous algorithms that run in a generic Cypress USB interface chip.
We use Resonessence designed, advanced power line processing circuits that can reliably deliver more voltage range than the USB provided 5V, and we maintain the SNR of the power supply to a degree such that HERUS exhibits well over 100dB of SNR at the headphone output. HERUS also has a very low 0.2 Ohms output impedance that prevents external noise sources coupling into the output.

All Resonessence products feature upgradable firmware and hardware and despite its physically small size, HERUS also contains Resonessence upgradable hardware and firmware.

HERUS is machined from a solid block of aluminum and is 63.5mm (2.5in) long, by 31.7mm (1.25in) wide and 19mm (0.75in) high. It has just two connectors: a USB type ‘B’ socket on one end and a TRS 1/4inch Stereo Headphone connector at the other end. HERUS, like all Resonessence products is Designed, Manufactured, Tested and Shipped in Canada.

The total distortion (THD) on any HERUS will always be better than 85dB (ie less than 0.005% distortion) and the noise (SNR) will always be better than 100db, typically 108dB. More detailed specifications are:
Asynchronous USB Audio 2.0 PCM bit width 24 or 16 Bits (If provided with 24bits HERUS uses them all, but it works with 16 bits also)
Supported Data Rates 44.1, 48, 88.2, 96, 176.4, 192 and 352.8 Ks/S
Supported Formats PCM, DXD and DSD64/128 Uses DoP protocol 1.1 over USB for DSD
Operating Systems MS Windows, MAC OS and Linux Use the Resonessence Thesycon Driver for USB Audio 2.0 on Windows
Output Signal Level At Maximum Volume level 2.4 VRMS
Output Impedance 0.2 Ohms
SNR at least 100 dB, Typically 108dB
THD at least 85 dB, Typically 90dB
Power Into 32 Ohms 126 mW
THD + N 0.0035 (89) % (dB) Typical
Power Into 60 Ohms 95 mW
THD + N 0.0032 (90) % (dB) Typical
Power Into 300 Ohms 19 mW
THD + N 0.0032 (90) % (dB) Typical
Power Into 600 Ohms 9.5 mW

THD + N 0.0032 (90) % (dB) Typical

HERUS will enumerate to the controlling computer and register itself as being able to handle volume control internally. Almost all music player applications will then send control commands to the HERUS which it will use within the ES9010-2M DAC chip to implement high performance 32 bit volume control processing. This is significantly better than the volume control implemented in the music player software.

HERUS is easy to use: plug HERUS into a USB 2.0 (ie High Speed port) [with USB Audio 2.0 enabled if on MS Windows] and select HERUS as the output device in your system control panel. That is all there is to it…

IMPORTANT Please note: some (if not all) software on the PC, MAC and Linux will, the first time HERUS is connected, set the volume to 0dB. That is, to the highest volume level. This may be very loud in the headphones. On subsequent connections the music player application will recall the last volume setting, but we have seen instances where plugging into a different USB port again sets the volume back to 0dB. Consequently, we strongly recommend that you plug the HERUS into any new port on your computer with the headphones unplugged, and set the volume to a reasonable level prior to plugging the headphones into HERUS.

Additional note: the volume level may rest to full volume if the headphones are swapped out while music is playing – please pause the music while you swap headphones when using HERUS. For more details see this FAQ note.
A note about the IPhone. We are overwhelmed with questions about HERUS and the IPhone. Thank you all for your interest! The simple answer you are looking for is “Yes – the HERUS works with the IPhone“. Learn more about IPhone and Android with HERUS. (There is a very brief FAQ here.)
Finally, you may, if you wish, use HERUS as other than a headphone driving DAC. For example, when driving a power amplifier you will find that HERUS is a capable and high performance system component. It is perhaps the optimum and lowest cost solution to accessing DSD music from your computer collection. Read our FAQ on this question for more information.

Resonessence Labs


€348.00 EUR




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