Gramophone Dreams #39: HoloAudio May D/A processor & Intona USB isolator Page 2

Tim Connor's USB care package also included a 0.2m length of Intona Professional Impedance Controlled USB cable ($450), which I inserted between my Mac mini and the Intona isolator. Between the isolator and the May DAC, I used a 5m Cardas Clear Serial Bus USB cable. Alternately, with my portable MacBook Air as the source, I connected the May DAC to the Intona isolator with a 1m AudioQuest Diamond USB cable.

Out of respect for Tim's opinion, I carefully examined the effects of these Intona products; however, except where noted, all critical observations about the HoloAudio May DAC made below were accomplished without Intona isolation.

Many products I review start out sounding wrong in a variety of ways and then, in a day or two, sober up and sound right. To my surprise, with the May DAC, the very first album I played, Folketoner ("folk songs"), sung by Det Norske Jentekor (the Norwegian Girls' Choir), sounded more fundamentally right than any digital reproduction I have experienced in my little bunker (24/44.1 FLAC 2L/Qobuz). The sound quality difference between it and the Spring DAC was not subtle. The May DAC made recordings sound considerably more "factual," like this is how it is supposed to sound, in a very unobtrusive way. Everything I write after this will serve only to amplify and verify that observation.

"I once was lost, but now I'm found." The spirit-soothing hymn "Amazing Grace" will outlast the planet it was formed on. Written by poet, clergyman, and reformed slave-trader John Newton (1725–1807), its simple form frames an exquisite incantation that testifies to our shared need for truth and redemption. Among a host of others, folk singer Judy Collins is admired for her many (live) renditions of this powerful song. The May DAC made Collins's 1971 recorded version (from her album Whales and Nightingales, 16/44.1 FLAC Rhino-Elektra/ Qobuz) sound sweet and unaffected. I teared up during the first verse. Judy's voice, and the highly textured reverb surrounding it, opened my heart and kept my mind on the emotional power of every syllable of lyrics.

A few days later, I played this hymn again, and it was distractingly bright with a harsh glare on the top notes of Judy's voice. The choir was muddled. Then I looked at the May's display and realized that the DAC was set for oversampling. When I switched to NOS, the choir's voices separated and became more richly toned. The top octave of Collins's voice relaxed and stopped stinging my ears.

Noticing, at CanJams and audio shows, how gray and hard some DACs sound made me wonder: Do NOS ladder DACs sound unnaturally soft? My best answer is—perhaps. Or maybe not. Who could say for certain? Clearly some R–2R DACs do play on the soft side of neutral. After years with the Holo Spring, I can say for sure that it imparted neither a soft nor hard quality to the recordings it reproduced. I will go further and declare that this hard/soft neutrality, and the Spring's preternatural quiet, are what made it disappear so completely and interfere so little with the music it plays. The May DAC takes the Spring DAC's invisibility and Mohs-scale neutrality and adds push to it. Better than any DAC I know, the May recovers the natural pressure behind musical flow. No doubt, the May's massive power supply contributes to this effect.

In overall presentation, the May DAC reminds me of Mytek's $5995 Manhattan II DAC, which I reviewed in August 2017. Both are extraordinary at recovering music's force and momentum. Until I got the May, the Manhattan II was my favorite digital locomotive. It delivered a mesmerizing sense of music's forward motions. Now I think the May DAC sounds more powerful, and more straightforward, less digital, and just more there than the Manhattan II or the $2449 Schiit Yggdrasil, another favorite.

Over the years, I've developed a fondness for more digital bits. More than 16 bits makes recordings sound more correct and natural, while artificially elevated sampling rates seem to increase only the illusion of resolution while decreasing palpability and believability.

Pure, native DSD is another story. In my little world, DSD provides the most musicality today's digital has to offer. One of the chief reasons I fell in love with the HoloAudio Spring was how organically it played native DSD.

I am fortunate to have a CD, a 24/176.4 WAV file, and a native (5.6 MHz) DSD version of Argentinian music collective Puente Celeste's Nama. This masterful Todd Garfinkle recording (M•A Recordings M084A) was made in a smaller hall than Todd usually uses; therefore, the voices and instruments feel more immediate than other Garfinkle recordings. Nama was captured at 5.6MHz with M•A's Korg MR-2000 DSD one-bit master recorder and a pair of M•A's custom mikes with 16mm DPA omnidirectional capsules. The mikes were connected to the Korg with a 3m pair of Crystal Cable Ultra XLR cables. The sound on Nama is solid and scintillating but also completely relaxed and natural. This recording is an example of what I call utopian digital.

I listened to the DSD128 version of the Nama album using the RAAL Audio SR1a and Abyss AB-1266 Phi TC headphones, both transducers driven by my reference Pass Laboratories INT-25 integrated amplifier.

I like audio that feels (at least a little) like real people playing real instruments in my room. The May DAC, playing Nama, did that real-people thing extremely well. The volume was less than live, but images were lifelike, dense, and hyper-3D. With both headphones, imaging was a 360°, out-of-body experience.

OS: Then I pushed the oversampling button on the remote, causing an increase in the sample rate compared to the original, native DSD, prior to analog conversion, and everything got thinner and more spread out. The soundstage became even wider, but it was now shallower. The harmonic spectrum of vocal and guitar tones was reduced by at least 50%. Performers sounded like imitations of themselves. The audio pleasure factor was reduced by 90%. With oversampling, vividness, brilliance, and old-fashioned transparency were reduced. I found this unsettling. On the good side, there was a sense of greater image specificity and detail.

CD: Oversampling did not enhance my esoteric DSD files. I wondered if it would help my CDs.

I connected the May to my Integra DPS-7.2 CD player (used as a transport) with a Kimber Kable D50 Dataflex Studio coaxial. I played some more Nama.

Played via the May DAC, the Nama CD sounded less immediate than the DSD128 file or the PCM 24/176.4 file without oversampling. The sound was clear, with a nice flow and fine musical textures, but with softer bass and less precisely drawn soundstages. The May made the Nama CD sound relaxed, natural, and consistently engaging.

Still playing Nama, I pushed that OS button again (selecting OS PCM). The first thing I noticed was a reduction in reverberant sounds. The hall of the Goethe Institute outside Buenos Aires is not enormous, but it has a distinct reverberation that oversampling reduced by half. On the positive side, the recording now sounded more tidy and well-sorted. Detail was easier to notice.

To my surprise, when I switched to OS DSD, which converts PCM bitstreams to DSD, the oversampling added a strange, music-enhancing something—I can't say exactly what, but it felt like—don't laugh—assuredness. With OS DSD, CDs seemed quieter and less digital than with the OS PCM.

The more I listened to CDs with the May's OS DSD mode, the more it seemed the DSD conversion reduced that digital homogenization I referred to earlier. Maybe I stumbled on something.


And what about that Intona isolator?
During the last week before writing this, I began examining the effects of the Intona USB 3.0 Galvanic Isolator and its associated cable. When I first put it in, I jumped back. The sound changed more than I expected it would. For a short while, I could not say I liked what it was doing, but I know myself and figured expectations were affecting my judgment, so I left it in and forgot about it. Four days later, I sat listening to Anouar Brahem's The Astounding Eyes of Rita (24/96 FLAC ECM/Qobuz) and thinking, absentmindedly, this recording sounds amazing. Am I listening to the best digital anywhere? Better than my rich friends? Then I remembered the Intona and thought, wow, is this possible? The sound coming out of the Magnepan .7 speakers was sensuous in a way that reminded me of food, strong drink, and sex. Very undigital.

Then I took the Intona out.

And existential melancholy set in. The soundstage was drier, flatter, and smaller. Instruments sounded plain. Reverberation on the recording was noticeably reduced. Music was less intoxicating.

Then I put the Intona back in.

With the Intona wire and isolator, music sounded more fascinating and complex, which, in my view, is what high fidelity is all about (footnote 2).


In sum As the digital anchor in my ever-changing audio systems, the HoloAudio May DAC (Level 3 KTE) exhibited a force and gravity that exceeded even the mighty Mytek Manhattan II. It demonstrated a natural quietness that exceeded my former reference for natural quiet, the HoloAudio Spring. It exhibited a unique type of understated liveliness that exceeded the Yggdrasil and Chord Qutest. The May's true-to-life demeanor made recorded music seem infinite and beautiful. Best of all, it made me feel good about our collective digital future. Bravo, Jeff Zhu. Thank you, Tim Connor.

Footnote 2: Herb asked me to see if I could find any measured reason for the Intona's improvement in sound quality. However, with data sourced from my MacBook Pro and the Intona connected to the HoloAudio May's USB input, I couldn't find any difference in the May's analog output signal than when the laptop was connected directly to the processor. This echoes my experience with the AudioQuest JitterBug and the UpTone Audio USB Regen, both of which I found improved sound quality despite my not finding any measured reason for the improvement.—John Atkinson


MhtLion's picture

Many reviews/experiences I read elsewhere point to that May may be one of the best DACs for DSD. I strongly recommend using HQPlayer to oversample any DSD to DSD512. I believe using HQPlayer for OS is clearly better than using May's own OS function.

Bogolu Haranath's picture

Next HR could review the PrimaLuna EVO 100 tube DAC with tube clock ($3,000, reviewed by Hi-Fi News) :-) ........

Charles E Flynn's picture


I literally spent hours trying to find DAC whose performance could be improved with this device. None of the high-end DACs cared one way or the other. They continued to work just as well as they did without Intona. After much frustration, I pulled out my old and discontinued Schiit Modi 2 USB which I know is sensitive to USB (power) noise and managed to eek out a bit of difference. Here is the Modi 2 directly hooked up to my PC:

Bogolu Haranath's picture

ASR said essentially the same thing about AQ Jitterbug ...... Also, JA1 did not find any measurement differences with Intona or Jitterbug ...... See, footnote 2 :-) ........

hb72's picture

On my DAC the AQ JB does a big difference in treble, also mids and bass. More analog if you want. Also ifi has excellent products that do similar things. Measurements that do not cover the essential improvement may be meaningless. As much as the proof of the pudding is in the eating and not in mass spectroscopy, the single most relevant test remains a long term listening test on your very own equipment. Here the JB and ifi’s purifier make a real difference.

Glotz's picture

Here is the more important section of the 'review' that the Earless Dude at ASR stated:

"What is that? You hear an improvement? Have a loved one put the isolator in and out of the loop of the USB connection 10 times. If you can tell reliably 8 out of 10 times and can document it in a video, I will pay you $350 so you can buy this product. Otherwise, it is not the spoon that is bending. It is you!"

Lol.. your EARS are lying to you now. Not that his tests are inadequate! YOU ARE. At least ASR is great comic relief.

"If you can't measure it, it doesn't exist!"

hb72's picture

That is indeed quite funny.

dc_bruce's picture

Still trying to get my brain around at column entitled "gramophone dreams" that concerns a DAC.
So, are measurements of DACs meaningless? Has Mr. Atkinson been wasting his time all these years, measuring digital stuff?

Jim Austin's picture

Stereophile has rarely measured equipment reviewed in columns. However, JA has performed measurements for a follow-up review. Those measurements will appear in the September issue.'

Jim Austin, Editor

Norbert2nd's picture

Dear Jim,
Having had a look at the measurements and diagrams I was really wondering if those and the listening have been made with the PLL enabled. If you look at the J-Test published on ASR there is one diagram titled "J-Test PLL On vs Off". JA's measured jitter diagram to me look more like the PLL Off curves.
Can you comment on this? The PLL setting has never been mentioned in any of the articles and due to the somewhat hidden access to configuration mode of the May-DAC it can easily get overlooked.
Thanks & best regards

John Atkinson's picture
Norbert2nd wrote:
Having had a look at the measurements and diagrams I was really wondering if those and the listening have been made with the PLL enabled. If you look at the J-Test published on ASR there is one diagram titled "J-Test PLL On vs Off". JA's measured jitter diagram to me look more like the PLL Off curves...

I looked at the ASR jitter measurements of the HoloAudio May - see - and the measurement with the PLL on looks superficially similar to mine.

In any case, I measured and listened to the May in the condition in which it had been auditioned by Herb Reichert. My measurements and my followup review will be posted to the Stereophile website in a week or so.

John Atkinson
Technical Editor, Stereophile

tonykaz's picture

Brilliant observation Mr.dc bruce.

Of course, the dollar costs involved in 33.3 are staggeringly outrageous, which sort of makes the constantly improved digital options our prefered direction over this next decade.

Its seems that we should've had another NEW music format by now! These Music Format systems don't have a long & useful life. ( We've been thru at least 7 competent and popular formats since the 1950s ).

I like 16/44.

Tony in Venice

Bogolu Haranath's picture

May be a new column called 'Digital Dreams'? ........ It has a nice ring to it :-) .......

Bogolu Haranath's picture

Other choices are 'Digital Planet' or 'Digital Corner' :-) .......

tonykaz's picture

There is a future out there, about to reveal itself.

I'm anxious about it.

It's kinda like we are about to witness Ben Franklin finally revealing the power of mother nature's electricity, after thousands of years waiting.

Something good is coming, I can feel it.

Tony in Venice

Bogolu Haranath's picture

We will have 3-D Holograms of musicians playing in our listening rooms :-) ......

tonykaz's picture

I'm looking for more knowledge and more access to accurate and reliable information in all things including our fatalities i.e. Cancers, Heart issues & Drug addictions.

I'm anticipating a significantly improved transportation system and implementation of Thomas Jefferson's Declaration of Independences famous promises.

What Society is doing now is the Prelude to Thomas Piketty's forecasting. ( along with the majority of the World's Economists )

Our little music systems will continue to improve, just like they always have.

Tony in Venice

tonykaz's picture

Who are you talking a-boot?

Tony in Venice

ps. Piketty is the French Economist Professor

tonykaz's picture

Tony in Venice

Jim Austin's picture

Let's delete the non-audio-related economic politics please.

Jim Austin, Editor

Bogolu Haranath's picture

Ok ...... I have deleted mine :-) ......

tonykaz's picture

Hello Mr.JA2,

Mr.Audiophiliac just presented a rather brilliant 'both sides argument' pertaining to Chinese Audio Gear in our USA Marketplace.

I think he nails the critical Service aspect of outfits not standing behind their products.

Steve G has been one of your greats.

Thanks for being there for us.

Tony in Venice

ps. for the record, China has been a quality leader in manufacturing for the last 500 years or so.

Jim Austin's picture

Stereophile is agnostic on place of manufacture. We do however try to provide information that will allow our readers to make their own decisions; information on place of manufacture can be found in the Specifications box in every formal Stereophile review.

Of course, customer support is crucial. To secure a Stereophile review, a company must demonstrate that they are able to provide adequate customer support to U.S. buyers, whether it's through a dealership or online. If a product cannot be repaired in the U.S., or shipped overseas and back quickly, then there should be a mechanism for rapid replacement.

Jim Austin, Editor

Bogolu Haranath's picture

Only a French economics professor can 'amass a wealth of gigantic' intelligence and knowledge :-) .......