Link Spotlights

Legendary Quality From Shure!
Anthem
Gen. 2 MRX Receivers From Anthem!
 photo gifss_zpsfb38418c.gif
Premium High-Res D/A Conversion!
”Learn
Audiophile Power Cords/Distributor

Thursday, July 17, 2014

Audiophile Headphone Review!
Oppo PM-1 Balanced Planar Magnetic:
Airy, Open Tone/Easy On the Ears






Brevis...
Price: $1,099
Likes: smooth response, comfy
Dislikes: Limited isolation
Wow Factor: "No fatigue here"


by John Gatski
  I received the Oppo HA-1 headphone amp and the PM-1 headphone at the same time. (Check out the separate Oppo HA-1 Review).
  The $1,099 PM-1 features a planar magnetic ribbon driver design in a compact, impressively lightweight frame with adjustable ear cups, and balanced or unbalanced operation. The key to the PM-1’s performance is the planar magnetic driver, which offers a smooth, even response — without peakiness in the treble. Planars also project a wide and deep sense of space that is perfect for headphone listening.
  Planar magnetic design has been around for about 40 years. It is basically ia hybrid design utilizing the principle of magnetic speaker speaker design and electromagnetic. Like a dynamic headphone — with their standard magnet drivers, planar magnetic headphones use a magnetic field that surrounds a conductor, which has an electrical current flowing through it to drive the speaker diaphragm.
  But the PM-1, like an electrostatic driver, utilizes a diaphragm of consisting of a thin sheet of flexible transparent film. Additionally, the PM differs from the electrostatic by using thin, flat electrical conductors to charge the diaphragm. Additionally, the Oppo PM-1‘s unique 7-layer diaphragm, double-sided spiraling coils, and an FEM-optimized magnet system enhances the headphone’s performance.
  Many audiophiles believe the contiguous diaphragm surface creates a more natural sound than standard dynamic drivers, and in recent years, companies such as HIFiMAN and Audieze have been part of the technology's resurgence.
  The PM-1 was designed by Igor Levitsky, a top-flight acoustical engineer who was involved on BG Radia's planar magnetic tower speakers and SLS ribbon loudspeakers. I met with an Oppo rep. and Levitsky last winter to audition the PM-1 and HA-1; I came away impressed with the pre-production headphone.

Hi-Res listening with PM-1, Android Phone and HA-1


  Unlike other planar magnetic HPs, the Oppo PM-1 is fairly lightweight — at 395 grams. Its lightweight aluminum frame features padded headband, adjustable ear pieces and removable able ear pads. Spec wise, the headphone are rated from 10 Hz to 50 kHz, though the usable range is in the 40 Hz to 20 kHz spectrum with a gradual roll-off in the high treble. Sensitivity is a very good 102 dB at 100mW. Maximum input power is 500mW continuous (2W pulse). The PM-1’s system impedance is 32 ohms, which is moderate in its ability to be driven. I found that most of my portable devices could drive the PM-1 to louder levels — if necessary.
  Oppo goes all out in its PM-1 packaging: a wooden storage box, a carrying pouch and extra ear pads. It also is available with an optional $79 headphone stand. To provide the most in listening flexibility, the headphone package sports a 2-meter unbalanced (optional 2- and 3-meter balanced cables are available, with OCC construction/Neutrik termination, at $129 and $149), as well as a shorter, small gauge, 1/8th-inch connector cable for portable devices. The detachable L-R cable ends plug in to their respective ear connectors.

The set up
  I put the PM-1 through its paces with numerous headphone-enabled audio gear including the Oppo HA-1 and other onboard HP amp-equipped audio devices: TASCAM DA-3000 recorder/player, TASCAM DR-100 Mk II hi-res portable, AK 100 portable hi-res player, Resonessence Concero HP DAC, Benchmark DAC2 D, Mytek Stereo 192 DSD DAC, and the Parasound Z-DAC/headphone amp. Headphone-only amps included the Benchmark H1 and the Bryston BHA-1, which also is balanced.
  Material ranged from well-recorded CDs to 24-bit and DSD hi-res sources. DAC-to-source interconnects were provided by WireWorld and power products, including power cords and strip, were courtesy of Essential Sound Products.

The audition
  Right off the bat, the PM-1’s sound was essential planar magnetic — a smooth, balanced, yet detailed tonal quality with just a hint of mid-bass rise. After a few days of break in with a CD on repeat (moderate level please; turning the HP amp wide open can destroy the drivers) the mid-bass bump was less noticeable.
  The first thing you notice about the PM-1 is how nice the ear pieces feel around the ears. The headphones definitely felt lighter than the HIFIMAN Reference HE-6 that I have auditioned, which weighs about 200 grams more. The PM-1 is quite comfortable —  without any focused pressure on my eyeglass arms. It also felt less bulky than my reference AKG K702s. Not quite as comfortable as the Shure SRH1840, but it is not that far off.
  With hi-res music, such as the Anthony Wilson Trio - Our Gang SACD, the warm jazz guitar/Hammond organ/drums, minimalist recording came shining though with its essential accuracy, including that wonderful space around the drum cymbals. The PM-1's top end is super smooth. Its signature, indeed, is similar to a quality ribbon speaker on the top end.

A perch for your PM-1: Oppo's $79 optional HP stand


  On the Gene Bertoncini — Body and Soul SACD, the transient response on Bertoncini’s guitar fingerpicking, was out in front with a nice spread in the L-R. The energetic percussion on the Flim and the BBs — Tricycle SACD was airy with solid extension on the top end as well. Unlike some ribbon speakers, I did not notice a major roll-off above 12 kHz-15 kHz.
  On all kinds of music, including Classical, Jazz and Pop, the PM-1 excelled in its delivery. These ‘phones are quite accurate, yet smooth, without the significant low treble and bass bumps, headphone companies often incorporate in their designs to get a more pronounced, “pleasing" tone that is often not accurate.
  The Oppo PM-1 is really clean from the high bass to the top-end — with that bit of boost in the midbass. To my ears, they just get out of the way and let me hear the recording. And of course because of the Oppo HA-1’s super headphone amp output, the PM-1 is a perfect mate for its electronic stablemate. The HA-1 ‘s extra clarity on the top end and well-spaced imaging, complements the PM-1's planar magnetic gradual roll-off character.
With hi-res music, such as the Anthony Wilson Trio - Our Gang SACD, the warm jazz guitar/Hammond organ/drums, minimalist recording came shining though with its essential accuracy, including that wonderful space around the drum cymbals. The PM-1's top end is super smooth.

  I did connect the PM-1 in the balanced mode, with the Oppo HA-1 and the Bryston BHA-1 headphone amps. Though some claim improved sonics via balanced HP connection, I could not hear any difference between the unbalanced or balanced from either headphone amp. Maybe the balanced gives you a little better SNR numbers, but, in my real world setup, it was not audible.
  The PM-1's sounded terrific on most any HP-equipped device. From a host of tested portable and DAC/HP amps, to home recording gear, the PM-1 never disappointed me. The PM-1 sound impressed my ears when using a multitude of portables: the Sony PCM-D100 handheld PCM/DSD recorder, the portable Astell and Kern AK100, the hi-res TASCAM DR-100 Mk II hi-res recorder  and my Android Dell tablet with Resonessence Concero HP. I had no problem driving the headphones with any of the portables.
  I even used the headphones for several recording sessions with the TASCAM DA-3000 master recorder. While tracking a direct-to-stereo DSD acoustic guitar session I appreciated its smooth, fatigue-free transient delivery and all-day comfort. Being an open phone, they do not seal out much external noise.
  I did not have any other planar magnetic HPs on hand for comparison, but in comparison to typical magnet driver 'phones, the PM-1's sound is balanced and accurate — with less emphasis in the treble. Similar to what I have heard in sessions with the top-end HIFIMAN planar magnetic models, but the Oppo is more commfortable, at least on my ears.
  Withs its satisfying performance assured, the Oppo’ PM-1‘s packaging is just icing on the cake. The optional headphone stand enables easy access and a classy display of these premium 'phones; the wood storage box gives you a nice place to pack them away. After all, the PM-1 cost more than a grand. They deserve the royal treatment. The optional balanced cable and the standard unbalanced cable are made with a light cloth wrap, which exudes a high-end look and feel. 

The verdict
  All in all, Oppo did a great job with its inaugural headphone, the PM-1. It is not cheap, but in the high-end audiophile world, its price is reasonable, given its quality build and top-notch sonic performance. And Oppo goes out its way to give you extras for your money (a nice storage box, carrying case, 3-meter unbalanced cable and extra ear pads). If you are into ribbon-style headphones or just want an musical set of cans, regardless of the design technology, the Oppo PM-1 deserves a listen. A big ole Stellar Sound Award!!

 John Gatski is publisher/owner of the Everything Audio NetworkArticles on this site are the copyright of the ©Everything Audio NetworkAny unauthorized use, via print or Internet, without written permission is prohibited.

Saturday, July 12, 2014

Audiophile Review!
Oppo HA-1 DAC/Headphone Amp:
“Discrete” Output Nets Sonic Treat





Brevis...
Price: $1,199
Likes: ooh that HP circuit, 384 PB
Dislikes: line output not as good
Wow Factor: "hard to beat at 3X more"

by John Gatski
  After the 2011 release of Oppo's versatile BDP-105 universal player with ESS Saber32 DAC and quite good, knobless headphone amp, I wondered what the company could do with a dedicated DAC/headphone amp.
  With the proliferation of computer-sourced audio from HD Tracks, Acoustic Sounds, 2L, etc., and an increasing interest in quality headphone listening to showcase all that hi-res detail, a headphone amp seemed like a logical product for Oppo. I mentioned my idea to the Oppo marketing folks, and tucked the thought in my back pocket.
  Then at CEDIA 2013, Oppo told me, privately, that a hi-performance headphone amp/DAC was in development, as well as a set of planar magnetic headphones. The duo were slated for on sale status by the first quarter of 2014, and they delivered on time.
  The new Oppo HA-1 ($1,199) and the PM-1 headphone ($1,099) are, as I expected, fantastic performing, and not that expensive — in audiophile terms. In fact, the HA-1 — with its discrete HP output section, top-end ESS Sabre32 DAC chip, ability to play PCM up to 32/384 and all flavors of DSD — is a downright bargain. Oppo even listened to my request for a word-length indicator, a rarity in most DACs.
  (Review Update! EAN's Oppo PM-1 planar magnetic headphone review is now on line: click here!

Features
  The Oppo HA-1 is priced at $1,199 direct order. The unit is an attractive, large headphone amp/DAC that comes in a silver or black finish. The unit sports a front panel LCD display with several menus, including set up and input. The front also contains the unbalanced and balanced headphone jacks, large analog volume knob, push-on power button and the menu adjustment knob.
  The back panel includes analog balanced XLR and unbalanced RCA outputs, as well as analog RCA and XLR inputs for use as a basic preamp. Digital connections include SPDIF coax, TOSlink, and AES/EBU balanced XLR. There are no digital outputs or digital pass-through routing.
  The heart of the system is the ESS Sabre32 chip and the discrete, Class A analog gain components in the headphone audio path. A peek inside the HA-1 shows a large power supply and related parts and very clean PCB. Since this is a headphone amp first, the premiere design and parts implementation are focused on that circuit. The unit has user flexibility with its line outputs, but the output parts scheme is a bit more standard with typical op-amps. If you listen to an HA-1, the headphone circuit is where it’s at.
  Oppo’s Jason Liao said the HA-1’s implementation of a network of custom-selected transistors, resistors and capacitors “gives our designer the most design freedom and flexibility to achieve a good sound.”



Oppo upped the parts ante with the HA-1


  “If you open the chassis of the HA-1 you will see that the transistors are mounted on large heat sinks to support the Class A operation,” he explained. “The resistors are all 0.5% precision metal film, and the capacitors are either made by WIMA or are our own custom build.”
  The HA-1 is the utmost in versatility. For uncompressed PCM, it decodes up to the ultra-high sample rates at 32-bit/352 and 32-bit/384 through the USB input. Though rare, there are some 24-bit/352.8 recordings from 2L; none commercially available yet at 24-bit/384, but there are a few 384 A/Ds, and I made a few guitar recordings using an Antelope Eclipse A/D to test the HA-1’s playback at the highest rate, as well as playing DXD from 2L. To play ultra-high sample rate PCM, I used my Macbook Pro and Audirvana player software, as well as a Dell Venue 8 Android tablet and USB Audio Player Pro software.
  The HA-1 also is adept at playing DSD: at the standard 2.8 MHz (1X) sample rate and 5.6 MHz (2X) sample rate (native and DoP). It can also decode at the 11.2 MHz sampling rate in native mode, but I have yet to find any material in that format. All DSD is input via USB.
  The SPDIF and AES/EBU inputs handle up to 24-bit/192 PCM. The HA-1 can also play USB audio from iPod and iPhone up to 48 kHz sample rate (using the HA-1’s front panel USB input, as well as decode Bluetooth, beamed wirelessly from various sources, using AptX processing. Android devices can be connected to the rear-USB input when using OTG cable. USB Audio Player Pro even allows 24/384 via Android devices, which can be decoded by the Oppo.


At $1,199. the Oppo HA-1 is an outstanding DAC/headphone preamp — with the ability to connect to computers, tablets, and smart phones at the highest resolution available, as well as the typical digital player. When using the discrete headphone audio path, the sound is magic. Without hesitation, an EAN Stellar Sound Award.

  Spec wise, the headphone amp section via digital input boasts a 120 dB dynamic range and 111 dB S/N. The analog in/HP out are a few dB less in performance. Distortion is extremely low at any input/ output configuration.
  In my opinion, the HA-1 discrete analog path in the headphone stage sounds so good that I ended up using that output for headphone and as a line out to my various amps. With a simple audiophile 1/4-inch-to-RCA output adapter, the HA-1’s excellent, airy, detailed sound could be carried over to speaker listening. The op-amp enabled line outs are good, but the headphone section is exceptional — more space around the instruments, as delivered by 24-bit.

Easy to use 
  The HA-1’s operation is quite modern. In fact, the user-selectable screens look like touch screens., but are user controlled via the function knob. Oppo said it would have added considerable cost to add touch screen functionality.
  The input screen shows icons for all the various inputs: analog, SPDIF TOSlink and coax, AES /EBU, computer USB, mobile device USB and Bluetooth. The monitoring window features three screen options: a graphic spectrum plot to 20 kHz, VU meters, or the input status info screen; both screens also include word length, sample rate input, volume level and high/low gain status. Other on-screen menus include: high/low gain setting for better matching to headphones and external components, screen brightness, mute and analog/digital home theater bypass.
  As a Class A device, the HA-1 feels quite warm, bordering on hot. You don’t want to put other components on top. It could, however, keep your coffee warm. BTW, I have to thank Oppo for listening to my request for adding a word-length indicator. With the variety of output setting parameters on computer audio programs, you need a word length indicator on the DAC to ensure you are getting the best quality playback from native format playback.
  With more than 15 years experience with computer audio, I know what it is to fly blind with regard to computer digital output. Many times my Mac’s Core Audio system has mysteriously changed output from the music’s native resolution to either a reduced word length and/or reduced sample rate audio from its USB output or SPDIF TOSlink output. For example on Audirvana, I can play 24-bit/192 music after playing 16-bit/44.1 music. Nine times out of ten, when I switch to the 24-bit/192 music, the DAC indicates that I am getting 16/192. I then have to go back into the computer setting and manually select 24-bit. Without the word-length status on the DAC, I would not have discovered the word-length reduction.


HA-1 has all the eonnections covered


  If you are listening to computer-based audio, the only way to truly know if you are getting the native word length and sample rate is to have onboard status display on the DAC. And, like the Benchmark DAC2, the HA-1 shows active bits, not just the status bits. 
  Because of its wide feature set and utility, the HA-1 is not just for audiophiles; professional audio engineers and serious home recordists owe it to themselves to check it out. The quality of the discrete headphone circuit is such that it is an ideal DAC for computer mastering, tracking and mixdown tasks — in the same range as the Benchmark and Mytek audiophile/pro DACs. If you work with DSD, its ability to deliver all three sample rates means the Oppo has you covered for quality listening to the mixdown, or direct-to two track DSD recordings.

The set up 
  The Oppo HA-1 was utilized in three audiophile scenarios: as an audiophile DAC/headphone amp, as a DAC/preamp — via the discrete HP jack and adapter — and as a DAC/preamp through the standard op-amp line-outputs.
  I also tasked the HA-1 in my home recording studio. The HA-1 was used to monitor 24-bit/192, 24-bit/384 and DSD 5.6 MHz acoustic and electric guitar tracks recorded on a TASCAM DA-3000 or straight to the computer using the Antelope Eclipse A/D.
  I also did A/B comparisons with other DACs: Benchmark DAC2-D, Mytek Stereo 192-DSD, and the Teac UD-501, by routing the HA-1 output into the fast switching Coda preamp and outputting the balanced signal to a Benchmark H1 headphone amp.
  Headphones included AKG K702SE, Shure SRH1840, Sony MDR-7510 and Oppo’s new PM-1 planar-magnetic ‘phones. For line out monitoring, the Oppo fed a Pass XA-30.5 or a Rogue Audio Medusa amplifier, which powered MartinLogan Montis or Pass SR2 speakers. The speaker amp connection was courtesy of Alpha-Core. All analog and digital connections were through WireWorld interconnects. The AC was routed through Essential Sound Products Essence II power cords and power strip.

The audition 
  First up was audiophile playback of 24-bit/352.8 DXD classical music from 2L. A Dell Venue 8 tablet and USB Audio Player Pro software, relayed the tracks straight into the HA-1‘s USB input from the tablet, using an OTG USB cable. The AKG K702 SEs headphone was the headphone of choice for these sessions. On the Haydn/Bartok - Cello and Violin Duos, the HA-1 transmitted a gorgeous spread of these stringed instrument’s primary tones, subtle overtones and room reverb. I could hear the air around the strings, the tinges of room reverb and an amazing dynamic range. Great accuracy on the cello. The other headphones delivered the same consistent tonal signatures with their slightly different sonic attributes. The new Oppo PM-1 also was a good match with the HA-1 — with its silky smooth, airy ribbon character. Check out the separate review on July 15, 2014.
  With its discrete analog signal path, Oppo has managed to quicken the presentation of the Sabre32 chip; it’s a tad tighter sounding than an Oppo BDP-105 — with more energy on top and a well-proportioned stereo spread. When I did my Coda preamp listening sessions between the Mytek, Oppo and Benchmark, all using Sabre DAC chips, the Oppo was the least warm, but the detail just pops right out of the monitor system. The Oppo HA-1 sacrifices some of the warmness, which allows presence and top-end frequencies to breathe.



Amen for the word length/sample rate readout


  On a 24-bit/192 dub of Warren Bernhard - So Real SACD, the in-the-room drum cymbals were crystalline in their presence through the Oppo, and the Steinway piano tone was perfect. The Tuck and Patti — With Love CD, a minimalist recorded guitar and vocals album of pop standards, also sounded gorgeous through the HA-1. Patti’s vocal was full and out front and the acoustic and electric guitars provided a tasteful soundcape with a full-stereo image. Very nice.
  On the 24-bit/192 download, of John Coltrane - BlueTrain, the same positive sonic attributes emerged from cut to cut. A nice air around the drums, full horn tones and a generous helping of space. The horn was not harsh, but the brashness remained intact.
  On a PCM 24-bit dub of the Miles Davis — Someday My Prince will come, the cut titled Teo has a great intro: bass and drum cymbals, with a pronounced airiness around those cymbals. Again, not as warm as the Benchmark or the BDP-105 and other ESS Sabre 32 DACs I have auditioned, but I liked the Oppo’s tone. It is not too thin or too thick. The analog stage, to my ears, eeks out a bit more detail and instrument layering.
  The Oppo handles pop music with just as much ease. Though it is a slightly tighter presentation than other ESS Saber32 DACs, it is not harsh — just revealing. For example, the 2002 reissue of Willie Nelson — Red Headed Stranger through the HA-1, I could hear all of the detail and dynamic range of the Martin acoustic guitar, the room reverb, Mr. Nelson’s vocal hues, etc. Would love to hear a 24-bit remaster of that record.
  On the Jason Mraz - Love Is a Four Letter Word 24-bit/96 download, again, the Oppo opened up the presence a bit on the varied tempo songs, which are abundant in acoustic, electric and percussion instruments. Though the recording is maxed to 0 dB and pretty loud, it was not harsh through the Oppo. The Benchmark also sounded really good on this recording.


On the 2L 24-bit/352.8 Haydn/Bartok Cello and Violin Duos, the HA-1 transmitted a gorgeous spread of these stringed instrument’s primary tones, subtle overtones and room reverb. I could hear the air around the strings, the tinges of room reverb and an amazing dynamic range. Great accuracy on the cello.

  In comparison to the other DACs, the HA-1 is a bit more present sounding than the other Sabre32 DACs, extracting an increase in air that gives you the impression of more transient speed and openness. It gets closer to the coolness of the Teac UD-501's Cirrus CS4398, or the Analog Devices-equipped Benchmark DAC1, but smoother. The shades are not night and day, but the difference are observed via my chosen headphones and music.
  As a DAC/line output preamp for my Pass and Rogue Audio amps, the headphone jack was the clear winner compared to playing the music through the analog line outs on the back of the HA-1. The op-amp based line-out (balanced or unbalanced) does not quite have the same width and detail presentation as the headphone amp circuit. From a utilitarian aspect, it’s nice to have the line-out jacks to give you the flexibility to route signals to outboard gear, but the audiophile preference is the headphone amp output.
  Through both the Pass SR2 and the ML Montis speakers, the headphone jack-delivered audio featured a stereo image that was wider and deeper sounding, and upper-register piano notes and drum cymbals were more succinct than the regular line out jacks. Note to Oppo: gives us the discrete audio path for line output stage on version 2.
  For the money and the outstanding sound quality, there is not much to complain about with the Oppo HA-1. As mentioned, I would also like to have the discrete analog gain stage in the line-outputs. And since it has this wonderful DAC, how about an onboard media player, maybe an SD card or at least USB drive with onboard player software — like the Resonessence Invicta. These additions would be more money, but maybe it could be made for under $1,500? 

The verdict 
  At $1,199. the Oppo HA-1 is an outstanding DAC/headphone preamp — with the ability to connect to computers, tablets, and smart phones at the highest resolution available, as well as the typical digital player. When using the discrete headphone audio path, the sound is magic. Without hesitation, an Everything Audio Network Stellar Sound Award.

 John Gatski is publisher/owner of the Everything Audio NetworkArticles on this site are the copyright of the ©Everything Audio NetworkAny unauthorized use, via print or Internet, without written permission is prohibited.







Thursday, June 26, 2014

Audiophile Review!
Resonessence Labs Herus
DAC/Headphone Amplifier:
Big Sound From Mini-Converter






Brevis...
Price: $350
Likes: sound quality, price
Dislikes: where did I put it?
Wow Factor: "ideal for mobile players"

by John Gatski
  In the past four years, I have reviewed three Resonessence DACs in various price ranges, including the diminutive-sized portable Herus reviewed here. I have to say they all have an essentially balanced, smooth sonic signature that varies in refinement, based on the price.
  The $350 Herus reviewed here is the smallest and lowest-cost Resonessence DAC, but it is a hi-fi product that gets you into the high-end sound without the bells and whistles and the extra expense of high-end DACs. And it is perfect for those on the go with smart phones and tablets that are capable of transmitting native high-res DSD via DoP and PCM up to 24/352.8. (In fact, the Herus will play 24/384 material at the 352.8 rate).

Features
  The Herus DAC is only 3-inches long and 1.2-inches thick with a USB B female connector on one end and a headphone jack on the other. The logo illuminates blue when it sees a signal. Nothing fancy.
  The heart of the Herus is the mobile ESS Sabre DAC ES-90102M chip, optimized for USB 2.0’s low-current, 5V DC power. Although its numbers are not as impressive as the mighty ESS Sabre32 flagship DAC chip, it retains much of the balanced, warm, smooth and detailed character of its more expensive siblings.
  The Herus DAC can decode up to 24/352.8 (DXD) in PCM and up to DSD 2X (5.6 MHZ/128X) via DoP. Gain for the Herus is adjusted in the playback program, but it is a hardware volume control in the Sabre chip that is software controlled. The audio is all processed in the DAC chip.
  Resonessence President Mark Mallinson said the volume must be handled by the chip to ensure proper DSD decoding via DoP. “If it was doing a software volume, DSD wouldn't work — since it relies on bit perfect audio from the player program,” Mallinson explained.
  The DAC spec is whic is listed at 100 dB S/N and dynamic range, but Resonessence claims actual performance is -106 to -108 dB. This chip was designed to offer good performance at USB 2.0-supplied 5V,500 mV power. The typical power consumption ranges from 126 mW with a 32 ohm headphone load, to 9.5 mW with a 600 ohm headphone load. The THD plus noise spec ranges in the .003% region with most headphone impedances, not as good numbers as its big brothers’, but decent for such a low-power device. In fact, the numbers don’t truly reflect how good it sounds.
**For Mac, the Herus works with most computer players, including Audirvana, Pure Music, AudioGate, and iTunes and a host of recording/editing playback systems. In my experience with the Mac and Herus, it worked well with all the programs I tried. Some Windows programs may need a driver.
The teeny Herus is a downright super bargain at $350. Great sound with a smooth, detailed character, good separation and the ability to drive most headphones Herus works with computers, Android tablets and phones, and iPhone and iPads. 

  As or maybe more important, the Herus portable DAC headphone amp is a perfect companion to all the USB-equipped portable devices that inhabit our modern world: tablets, smart phones, laptops, etc. My review focused on Mac computer and Android phone and tablet, but Resonessence says that Herus also works with ipad and iPhone, but you need the camera dock to get USB connectivity.
  Not normally promoted as a recording tool, I found  Herus a quality listening tool for audio professionals and home recordists who want to monitor their recorded projects via headphones — without having to carry around a bigger headphone amp/DAC and the tethering-AC cord. I used it with a variety of editing and playback programs, and it worked with ease. Even did a final quality check on a 24/352.8 acoustic guitar stereo recording that I had made when traveling on a short vacation.

The setup
  I had several DACs on hand during the evaluation process, including my other USB-powered Resonessence, the step-up Resonessence Concero HP ($850) for comparison, and my high-end Mytek 24-192 DSD and Benchmark DAC2D. For headphones, I used the Shure SRH-1840, Sony MDR-7510 Professional and the AKG K702 Anniversary.
  For audiophile playback I started off with my Macbook Pro and Audirvana software, and later plugged into a Dell Venue 7 tablet with the USB Audio Player Pro app (separate review upcoming) and a HTC Harman-Kardon Edition smart phone with USB Audio Player Pro. USB Audio Player Pro allows most Android devices to play up to 24/384 PCM playback out the device’s USB port. You just need an OTG cable to enable the host player mode to transmit the audio, but it works.

The audition
  As soon as I plugged the Herus into the Macbook Pro, I selected the Herus in the Mac’s Core Audio Audio settings, and it was immediately recognized; no extra software needed. The volume is controlled by the program software; no knobs on this little DAC. I played the music via Audirvana.
  First up, my download of the 2L 24/352.8 DXD-recorded Mozart — Violin Concertos (three separate performance — the D, G and A Concertos). Via the SRH1840, the violin tones were vivid with a good deal of the string harmonics and room reverb that I hear with more expensive DACs. And the imaging and separation was quite good. The balanced, yet smooth, tone, indicated the ESS DAC chip underpinnings; you could definitely tell it was a Resonessence DAC.
  Compared to the almost $850 Concero HP, there was slightly less width and depth and a tinge less sparkle to the upper end transient tones, but not a major league difference. I rather liked the sound of this diminutive-sized HP amp/DAC. The DAC2 and Mytek, of course, had more inner detail and increased imaging than Herus. But those are $1,500 plus DACS. You expect that. For the Herus to be in the ball park is a testimonial to its design.


Herus setup with Dell Venue tablet, Shure HPs
 and Pluggable USB 2.0 powered hub


  I switched to my AKG K702 HPs and cued up a 24/192 dub of Miles Davis’ “Teo,” a cut from the reissue SACD of Miles Davis — Someday my Price Will Come. This 50-year old recording has a fantastic -sounding drum set up; the cymbals and snare are quite detailed and amply spread out. You can also hear the recording studio room reverb tails and decay. The better the DAC, the better the percussion sounds. Guess what. The little Herus does a pretty good job of nailing the transients and reverb tails, not to the degree of the Benchmark, but enough to know it is high res. Oh, and did I mention it was $350?
  I played several albums of DSD downloads via Herus and Audirvana. As with PCM, it has that signature warmth and balanced of ESS DACs. I played one of my own DSD 5.8MHZ/128X jazz guitar recordings, as recorded on a TASCAM DA-3000 hi-res recording. To my ears, DSD/2.8 MHZ/128X is a little tighter in the bass than standard DSD 2.6 MHz/64X.
For my computer recording rig, the Herus came in handy. No power cords and components looking for a place to be placed. A simple little rectangle that takes up very little space. Just plug in the phones and record, edit, master, etc. The little guy is plenty good to check the quality of your work with good headphones.

  For my computer recording rig, the Herus came in handy. No power cords and components looking for a place to be placed. A simple little rectangle that takes up very little space. Just plug in the phones and record, edit, master, etc. The little guy is plenty good to check the quality of your work with good headphones.
  I used Herus with Apple Soundtrack, GarageBand, and Audacity. It was instantly recognized and I never had a single glitch. Volume was adjusted in the program. I also plugged into the Herus to monitor a 24/352.8 acoustic guitar recording I made with my recording gear and the Mac. It was just what I needed for the final edits and QC.

Ideal for Android players
  To take advantage of Herus’ portability, I added a OTG cable to my Dell Venue 7 tablet, so it could play high-res music from the USB Audio Player Pro Android program. You need the OTG to enable the host mode and connect the required USB A-to-USB B cable to the DAC. Tablets only have micro connectors and cannot connect to otherwise-terminated, outboard USB gear without this adapter
  A word of warning, the tablet or smart phone supplies the power to the DAC, which can run the battery down in just over an hour if the DAC does not have its own power, like Herus. You can avoid power loss by connecting the Android device to a powered USB hub with the other connection on the OTG. To enable this powered setup, plug in the OTG cable into the Android devices micro USB port. You then connect the OTG adapter cable’s female micro USB output port to a micro SD male-to-USB A (standard or mini) male connector cable, which is then plugged into the powered USB powered hub.
  You then attach a USB A male-to-USB A-male (or USB A male mini) cable into the other OTG input: a USB A female port. That cable is connected to any A or Mini-A port on the hub, and finally, the USB A-to-USB B cable goes from the hub to the DAC. Voila, not only do you get native high-res PCM output from Android, the DAC is powered independently, and the Android device is charged from the same USB connection. It sounds complicated, but in reality it is easy to hook up, and you can listen for hours as the battery stays charged
  On some Androids you can keep the battery charged without the powered hub, by plugging the devices’s micro USB terminated charger straight into the OTG and plugging into the other OTG port with a USB A-to-B cable connected straight into the DAC. My Dell charger provided enough power to run the DAC and charge the battery — without the hub. (The powered hub also allows connection of external hard drives to Android devices, but we will save that for another day.)
  Once I had the DAC connected to the Android, I fired up USB Audio Player Pro.This dandy PCM playback program allows most Android phones and tablets to play and transmit the native PCM audio to an external USB DAC — up to 24/384.
  Operation was a snap with USB AudioPlayer Pro; it allows for volume control and simple playback preferences. It is an amazing music player for $7. I played numerous bits of hi-res music, including high sample rate recordings with the Dell tablet with no problems. On the Mozart — Violin Concertos and Haydn/Bartok — Cello Duos, also a 2L 24/352.8 DXD, the sound quality via the tablet was as good through the Herus as the Macbook Pro and Audirvana playback, Clean, quiet, smooth and plenty of detail, especially for the money. High-end DACs from 5-10 years ago don’t sound this easy on the ears.
The Herus retained its good Android performance when I switched to the HTC 1 HK Edition smart phone, using the OTG cable, with USB Audio Player Pro installed. Screen was a little harder to see than the bigger tablet, but the audio was first rate. I even played back a 24/352.8 acoustic guitar stereo recording via the smart phone/USB Audio Player Pro and Herus.

  The Herus retained its good Android performance when I switched to the HTC 1 HK Edition smart phone, using the OTG cable, with USB Audio Player Pro installed. Screen was a little harder to see than the bigger tablet, but the audio was first rate. I even played back a 24/352.8 acoustic guitar stereo recording via the smart phone/USB Audio Player Pro and Herus. Man, do I love that set up. Sadly, the HTC phones does not charge from the hub while playing through Herus, but that is an Android problem.
  Any complaints? Not much. The size can have its own drawbacks. I misplaced it several times and it is so small, it was hard to find. Since it does 352.8, it would be nice to tweak it slightly so it could also play 384 sample rate music without downsampling. A sample rate or word length indicator would be nice, but you can’t expect too many bells and whistles — since it is North American manufactured and only $350.

The verdict
  My third Resonessence DAC and yet another winner. While the flagship Invicta was the ultimate Resonessence product — with a fantastic headphone amp and SD Card player onboard — and the Concero HP offered much of the same tonal quality in a down-priced, HP-only version at under $900, the teeny Herus is a downright super bargain at $350. Great sound with a smooth, detailed character, good separation and the ability to drive most headphones Herus works with computers, Android tablets and phones, and iPhone and iPads. During the review, it become my travel DAC — pairing it with my Dell tablet and USB Audio Player Pro. Load up the external micro SD card with hi-res PCM, plug in the DAC with an OTG cable, and away I would go with my Shure SRH-1840’s stuffed in the bag.
  With the Herus review now complete, Resonessence is now three for three in Everything Audio Network Stellar Sound Awards.

 John Gatski is publisher/owner of the Everything Audio NetworkArticles on this site are the copyright of the ©Everything Audio NetworkAny unauthorized use, via print or Internet, without written permission is prohibited.