Mike Piskor 2015

Airist Audio Heron 5 review

Disclaimer: The Airist Audio Heron 5 was sent to us as a sample in exchange for our honest opinion in this review. We thank Airist Audio for this opportunity. 

To learn more about amplifier products reviewed on Headfonics you can click here.

Note, this review follows our new scoring guidelines for 2020 which you can read up on here. 

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A new player called the Heron 5 has entered the battlefield and I’ve almost no information to share about Airist Audio apart from the fact they are a small team of smart people from the likes of MIT, Harvard to name but a few colleges and who have a passion for audio.

What I can say is that these newbies to the audio game have put together a very good amplifier.  Really, that’s all that matters these days.  Amplifiers have come a long way in the past few years and it seems like more delicious Summit level products are available than ever…these guys and gals are extremely bold with their pricing for their very first foray into Audiophile land.

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The Heron 5

At $1999, I can safely say the exterior build quality of the amplifier radiates quality in abundance.  She is hefty at almost 15lbs, utilizing a fully aluminum chassis from start to finish.  The power button feels buttery smooth and when active, the Heron 5’s volume knob lights up with a beautiful contrast in color to the surrounding black finish of the center of the dial.


The Dial

While on the subject of the dial, it feels very heavy and of high quality with a satisfying clink that can be felt for each volume position as you toggle it.  I am a fan of this type of tactility and dislike the slick and effortless volume knobs that are found in most other amplifiers.

That weighted appeal when I turn the volume up and down, maybe I am in the minority on that?  I don’t really know if that matters or not, but I like little oddities like that.  They also include what looks like a medical-grade power cable that is super dense and bulky.


I have a gripe…and it’s a serious gripe that comes in the form of the type of outputs and inputs some amplifiers are using in their designs: the Heron 5 has Balanced XLR and RCA inputs, but only ¼ outputs.  This upsets me to no end and I am a firm believer that this type of design needs to end…forever.


The unit has dual left and right balanced 3 pin XLR inputs as well as RCA, but the conversion from balanced to unbalanced is designed into the circuitry.

I want to rip what little hair I’ve left right out of my head when I see designs that tell you “Nope, you can’t have balanced.  We are just going to allow you to be teased with Balanced XLR’s, but will just remove the potential for a balanced output for no real justified reason.”  

This is such a pet peeve of mine.  Why allow for XLR 3 pin input but then convert to ¼ for the output?  This makes no sense.  Just drop the high ¼ output and swap it for a single 4pin XLR! Seriously, this makes me want to cry like a toddler and stomp and pout up and down the hallways of my condo.

Dual Unbalanced

The Heron 5 has a unique feature that I’ve not seen in an amplifier in a long time: dual ¼ outputs that are intended for different output impedance headphones.  High and low, I suppose?  I’ve no real details on it, as the website doesn’t offer any useful information on well…anything about the amplifier or the company that I can relay to readers here.

What I can say is that headphones like my Enigma Dharma D1000 ($1299 hybrid dynamic and electrostatic headphone) sound much better through the low ¼ output on the right side.  I feel like everything on the left-high output sound overdriven and if High Gain is always active.  I wasn’t able to find a single headphone, even demanding ones that sound better when using the left side output, as the left side is more prone to static and hum from a noisy source.

XLR Confusion

I have a 3.5mm male to dual XLR cable that bridges my sources, this cable works with my Mjolnir’s XLR input just fine, but does not function at all with the Heron 5 XLR input.  In fact, this 3.5mm to XLR cable works on every other amplifier I’ve ever had in the house with an XLR input.

When I pair the balanced XLR’s of the Mjolnir used as a preamp to the XLR’s on the rear of the Heron 5, I get a loud hum that makes listening impractical.

RCA Inputs

The RCA inputs on the Heron 5 I have seem to function perfectly, so things sound wonderful through that.  Mind you, I am using Audioquest $250 Mackenzie and $150 Red River’s that they’ve so graciously gifted to me to help out in this review.  These cables work normally with every other balanced product I had.

Of course, I had other brands’ XLRs from odd companies and even Monoprice, but all of them failed to work with the Heron 5’s XLR input.  I guess I am just unlucky…or wasn’t I?   Turns out the Heron 5’s designers specifically designed the amplifier to only work with certain cable types and certain wiring configurations with regard to only 3.5mm to XLR cables.  When I inquired about it, William at Airist Audio responded with this:

We wanted to avoid using a summing op amp on the balanced inputs to produce the single ended signal for the amplification circuit as this would be an additional component in the signal path and inevitably affect the sound.”

Basically, the amplifier does not work with a direct connection from a 3.5mm source output, to the Heron 5’s XLR inputs.  My USB DAC of choice is the iBasso DX90, which only has a 3.5mm output.  So, I normally run a simple 3.5mm male to XLR cable to use with amplifiers that have XLR inputs.  This cable setup results in no sound with the Heron 5 due to the configured wiring inside.


How It Works

However, it does work with certain other adapters and products like my ground loop isolator from Pyle: which is a thing that eliminates electrical noise and ground loops in various audio equipment.  The device has ¼ and XLR inputs and outputs, so when I connect my DX90 Dac to this Pyle box via XLR, then out that also with XLR to the Heron 5, I am met with perfect, beautiful sound.

So, if you want to use unbalanced to balanced connectors, you’ll have serious problems with the Heron 5’s XLR inputs.  3.5mm to RCA on the Heron 5 works perfectly.  3.5mm to XLR does not and you’ll need a device that grounds or splits the signal into separate channels.  A lot of amplifiers actually don’t do that.


For example, my Schiit Mjolnir cannot be used as a Preamp for the Heron 5.  You are met with a load of static and hum in certain configurations.

  • DX90 3.5mm Dac > Schiit Mjolnir XLR input > Mjolnir XLR output  > Heron 5 = severe hum and static due to wiring differences between the amplifiers.
  • DX90/any 3.5mm music source > Heron 5 XLR = no sound
  • DX90 > Mjolnir > Heron 5 = bad sound, but still sound coming through
  • Schiit Gungnir XLR out > Heron 5 XLR in = perfect sound
  • Schiit Gungnir > Mjolnir > Heron 5 = perfect sound due to a fully balanced cable setup.

Summed up, be careful what your rig is composed of, you might not get normalized sound.  I bring that up because I can use a 3.5mm source to the Mjolnir’s XLR input and still get the perfect sound.  I am not at all cool with how Airist applied this design, it limits me with what I can use and what I cannot use in a nearly $2000USD amplifier.

Sound Impressions


I’d like to alter my format for reviews just a little here, as I’d usually start off with the Bass experience and drop into mids, treble and other traits in that order.  This time, I’d like to start off with the general tone of the amplifier, which I find to be nothing short of immaculate and unlike most other amplifiers I’ve heard in an extremely long time.

The Heron 5 is easily the most smooth and effortless sounding amplifier that I’ve heard in years, easily besting the Burson Virtuoso, Schiit Mjolnir and Oppo HA-1 that I’ve available here for testing and comparisons.  I briefly got to sample the Ragnarok but found the experience to be overly sharp for my tastes and not worth investing time in acquiring for this review just for a comparison.


Smoothness is a lost art in component matching and owners of the Burson HA160 will understand what I am talking about.  Typically, I’ve found that amplifiers become more neutral and crisp as the price goes up.

In Summit level gear, accuracy and a clinical appeal is something that runs rampant like a hungry wolf, biting everyone and infecting them with some sort of nonsense idea that you are only supposed to listen to music for the accurate sense of tone it offers: it must be true to the track, screw anyone else who wants a lush, vivid and effortless appeal to their listening…you know…fun factor and such being something you shouldn’t invest time into finding.

I want musicality, not accuracy.  I am one of the types of listeners who do not care about how true to the recording my gear sounds.  If the track is hard, I am not interested in subjecting my ears to pain just so I can tell others my rig is neutral and accurate.

No! I want to relax and have what harshness is in the source to be absent or at least very dimmed so I can actually enjoy it.  This is subjective, my personal preferences: you like Lamborghini, I like Porsche.  Neither side is wrong and people listen for different reasons.  Some find bliss through an accurate tone and others like me do not.


In this case, the Heron 5 is more tuned for those who want to just relax and enjoy their music without a critical mindset haze that looms over those who are using the products in hand, or on the head for that matter.

Musicality is something most of the community seems to just not care about, so I am very proud to be on the opposing side view on this subject.   We are the 1%.  Before continuing, the amplifier is not boosted in quantities, so it remains fairly “neutral” in physical appeal; although I think everyone will admit to the amplifier being softer and smoother feeling than most amps in this price tier.

So in that regard, it is very musical and enjoyable, but will still offer a great sense of clarity that isn’t boosted anywhere with regard to quantity levels.


Effortlessness is uncommon these days and that super slick and vividly rounded-soft impact type of physicality is something I highly desire…and the Heron 5 has this quality in abundance.  Compared to the Mjolnir and Ragnarok, which sound sharper and snappier, the Heron 5 instead offers a more liquid-like of tonality.

I really like it and I’ve found myself regretting heavily selling my HD800 a few months ago.  Damn.  I shouldn’t have done that, so I’ve asked a friend for a loaner.  Softness and relaxing tone, without harsh impact and something that will dim down the excessive treble is something I’ve been unable to acquire for usage with the HD800, so I feel safe in saying that this Heron 5 is one of those amps that listeners like me are going to want to try to demo asap.

The Dharma has the same tone and setup as the HD800 in physicality and audio properties for the most part and both pair very nicely with it.

Tonal difference

There is quite a large tone difference when I use a balanced rig like the Schiit Mjolnir, to the Heron 5 in ¼ output: overly crisp to smooth as butter with the Dharma.  The HD800 and the Heron 5 are a match that I enjoy a lot and that forces the clinical HD800 sound more user-friendly and musical. If it does that to the Dharma, it would do that any similarly snobbish headphone as well.

The lack of harsh impact really shocks me sometimes and the overall relaxing physicality and slickness of the Heron 5 is definitely the most prominent quality the amplifier has to offer.  It is unique in this era of listening in Summit level gear, so I am very happy to finally have something that doesn’t sound clinical beyond the $1500 mark.



If you like Audeze bass, something that is of a more pure and liquid-like texture, rather than a Hifiman that is more thick and weighted feeling, you’ll love the Heron 5.  This amp puts out a hyper smooth low-end tone that is both warm and soft on impact, which again is something I highly desire.

Again, you purists out there may not really enjoy this type of a tonality, but you should enjoy the raw clarity and despite it being quite soft on impact.   I feel like this amp could easily make or break your headphone experience, so don’t expect an all-around great reference experience that will mesh with anything.

It really seems like this Heron 5 expects you to know full well that snappy headphones like the HD800 lose that sense of appeal and swap it for something really light on slam and kick.

The Heron 5 doesn’t seem boosted at all down below, which is something I would have preferred.  Moderate bass quantity is probably and objectively the best way to go, so I can’t complain.  When I cycle between this and my Burson Conductor SL, I am met with more bass quantity on the latter and the Heron 5 seems a more flattened in quantity compared to the mids.


Quality is certainly superior on the Heron 5, so that isn’t a problem. But, those who might be looking for a more bass-heavy experience or rig might want to use some EQ or light bass boosting via your musical source to obtain something more.  The Heron 5 seems plenty capable of responsiveness to boosting and I run with a +5dB on the bass end at all times with Realbassexciter (a free bass enhancer for Foobar2000) and it sounds fantastic and without any quality loss.


I detect no mid-range blossom effect, nor any recessed mids.  This amp emits a great linear feel from top to bottom, so it might not be the correct amplifier to accentuate the mid-range vocal experience of either the source or the headphone in the chain.  If you want that, I might consider something else, but if you are cool without much of a mid-range accentuation, I can’t begin to recommend this Heron 5 enough.

For vocals, I tend to want that softer appeal that is less sharpened and crisp and more elegant and relaxing and will happily sacrifice a mid-range pop for a more physically dense and soft experience.   This amplifier has that in droves, in case you’ve not gotten that point etched into you by this point in the review.

Audeze LCD3

The Audeze LCD3 responds incredibly well with the Heron 5, despite it being a bit of a forward bloomed headphone in the mid-range, it is almost no-issue.  I’ve found that the Heron 5 meshes well with most headphones in terms of the physical locale of the headphone (some headphones have a pushed back mid-range, some are upfront and forward sounding) and it only becomes an issue with the extremely forward sound signatures.

You’ll want to try to pick up something else instead.  However, for pretty much any other locale placement for mid-range (very recessed, moderately forward, and even right on the horizon of what you might consider being very forward) you’ll enjoy the amplifier.

Mids are vividly lush and I hate using that term, but it really fits here in the most significant way imaginable.  There is a fantastic rounded feel to everything that is super smooth.  I love this type of sound, as it is reflective of the Koss ESP 950 and other extremely smooth and effortless feeling electrostatics.

While on the subjective of electrostatic headphones, my hybrid dynamic/electrostatic Dharma D1000 ($1299) actually ends up sounding almost like the Stax 007.  In fact, I really can’t tell the difference between their mid-range clarity and overall physicality when I use the 007 on a lower end amplifier like the SRM1, which is a $450 used Stax amplifier, versus using the Dharma on the Heron 5.  Quite a feat, if you ask me.


The overall clarity on the Heron 5 is excellent, there is no doubting that, but I don’t feel it to be more than a step better than something like the Burson Virtuoso in the mid-range.  Both of them are well within competition levels to me.

Although, consider the Virtuoso is also a USB DAC and things start to bother me a lot here.  Maybe, Burson really invested more into making sure the mid clarity is exceptional, whereas Airist Audio might have tried to round things out and make everything very good instead of just one exceptional piece of the experience.

I think the Heron 5 is capable of more than what I can feed it, so a much nicer DAC would be wise to invest in, as my Gungnir and O2 don’t really mesh with it or do it justice enough to make me consider it leagues ahead of the Virtuoso in this area.


Once again, the Heron 5 lacks a slamming effect that I find immensely appealing on a subjective level.  I think owners of the HE-500 and similar trebly happy headphones will love this, as the Heron 5 offers that satisfying, dense appeal to the physical weight carried, but also keeps the upper end fairly linear feeling.  It has been a while since I’ve used the HE-500 and thought to myself the upper end requires a slightly toned down quantity, but excellent clarity and style are retained at the same time.

The Heron 5 is definitely within the proper parameters for usage with certain trebly headphones, but not something you should consider exceptional without EQ.  I don’t think the amp does justice to the HE-6, as it does sound rather thin to me and lacking power, but then again my 8w Mjolnir also seems a little underwhelming in regards to physicality with the exceptionally hard to drive headphones out there.

But, with some EQ you can get the HE-500 to sound lovely.  Just a little boost on the treble is what I prefer my HE-500 with and the Heron 5 again retains quality and density without feeling overblown or painful in kick and slam up top.


The treble is a little less bright and vivid that I would prefer and as I do with the low end, I tend to raise in a +2-3dB increase on the top end, if not to keep things lively for me and with my personal headphones.  With the Audioquest Nighthawk, this boost isn’t needed and for the most part, you probably won’t want to boost up top.  You might find yourself right in the perfect area for usage with the HD800…and boy, let me tell you, the HD800 sings with this amplifier like no other amplifier I’ve ever used with it in the past few years.  Holy smokes.

Sennheiser HD800

The HD800 from Sennheiser is an old cow now, yet still performs on a magnificent level compared to a lot of other Summit headphones.  Shockingly, the harshness up top gets muted just a bit by the Heron 5 and the end result is something I’ve desired for years, six years to be exact.

Ever since I’d first heard the HD800, I’ve been hunting for “that amplifier” that pairs exceptionally well with it.  To date, only the Burson HA160 did anything for me ( $450 used these days) and I’d come across few others that meshed with the rest of my gear well enough to keep using the HD800 with.

Most of those were way too pricey for me to begin to hope to own.  That isn’t the case anymore, the HD800, DX90 as my DAC, and Heron 5 as the last word in amplification literally made me not want to continue writing this review.  I sat for too long in my listening chair doing nothing at all, my projector screen was off, shut my door, and kicked the cats out of the room.  I’ve not been so satisfied with the HD800 in a long time.

Substance Factor

For me, the HD800 is not a headphone I enjoy, for the most part, and I had to acquire a loaner for this review after I’d sold my set a few months ago.  I believe it is overly thin and lacking, but the Heron 5’s substance factor is excellent and the HD800 responds well to that.  Things thicken up a bit and are much to my liking, so I’ve actually considered rebuying my own HD800 after experiencing this loaner HD800 again with my Heron 5 full time.

If you’ve ever wanted a more reserved treble that retains brightness and a sweet-like appeal on the HD800, you might want to invest in this amp or at least try to demo it with your HD800.  The Heron 5’s lack of impact up top and overall soft appeal really turned the HD800 into a headphone I want to use as my primary.

This type of musical sound signature meshing is rare for the HD800, so you purists out there will hate it, don’t bother.  However, those who like the softer and more relaxed sound signature on the treble, something a little reserved and less tizzy, will love it.

Sound Stage

Finally, the star of the show!  It has been years since I’ve experienced a solid-state amplifier sound this spacious and effortless.  The physical setup of this amplifier is a vast feeling and similar Burson products in general.  It feels odd to swap between it and some of my portable amps or my Mayflower O2 and I really can’t help but to feel a looming sadness when I am away from the Heron 5’s large sound field.

Recently, I’d about lost my cool when I read a few users on the headphone page of Reddit tell me that sound stage doesn’t matter and that it is nonsense, that there is no physical size differential between lower-end models not know for good staging properties and something like the HD800.

Superior Imaging

I actually had to take a break for a few days and just ponder what I’d read, due to those few being serious about their view on it.  The HD800 and similar headphones emit a very large image: that physical shape has limitations to where the sound starts and ends in an X, Y and Z-axis: stage forward, height and width, combined with the separation distance between.  All that you hear combined is the presentation or the “sound stage” and some products do well with this, some do not.

The Heron 5, at least to me, one of the better stereo imaging amplifiers I’ve yet heard.  She is expensive, but I think this is an end game amplifier for headphones like the HD800 that offer a large, spacious feel.  The difference between using this Heron 5 in ¼ and the Mjolnir in XLR balanced for my Enigma Dharma is noticeable: the Mjolnir lacks detail in stage forward realism and as soon as I swap to the ¼ on the Heron 5, I am met with a Stax 007 level forward imaging prowess.

Our Verdict

Airist Audio being a brand new company worries me a lot, due to the fact that a lot of brand new companies last a few years and then dissipate.  I hope that doesn’t happen, as I really like this amplifier.  But, the truth is that the overall clarity of the mid-range and the treble is roughly a step better than the Burson Conductor Virtuoso, which is a $1500 USB DAC and amplifier combo in one unit.

That extra $500 in the amp-online Heron 5 seems a little out of place to me.  However, I am fairly certain everything else is superior by comparison.  With that in mind, due to the exceptional smoothness of the Heron 5…absolutely, none of that matters to me and I’d shell the MSRP out for it without a second thought.


My gripes are that no amplifier should offer only ¼ outputs if they cost more than $599, but negate the usage of XLR by offering unbalanced output in the form of just ¼ and nothing else.  This isn’t cool.  Offer a balanced output if you have balanced input, which is how I want to see things from here on and with all companies who create expensive amplifiers.

Also, quality control on the XLR’s would have been nice and testing before shipment is a good idea.  I think buyers might want to know for sure their $2,000 amplifier works perfectly before sending it to them and that they might not care if the company tests and inspects it before you get it.  These guys are a tiny company, I can’t expect them to actually do that right now, so they get a pass for the moment since this is their first project.  However and in the future, they need to step up the quality control game to make sure this doesn’t happen.


At the end of all this, the Heron 5 offers a tonality that I’ve desired for neigh a decade in an amplifier and pairs immensely well with the HD800.  This amplifier sounded so good with my loaner HD800, that I, the guy who really dislikes the HD800, has repurchased the HD800.  Oh boy.  That is something I didn’t think would even happen again for a very long time and after the past few years of companies just shelling out the most neutral and dry products imaginable: the more expensive things get, the more clinical they get, and the less I like to pair HD800’s with them on my subjective level.

The Heron 5 is soft on impact and hyper smooth, offering a grand sound stage experience, excellent bass quality, and a lack of impact that I find incredibly addictive.  They might want to consider boosting the output power in a future model, as 5w output isn’t enough to get the job done on sets like the HE-6, at least not in my opinion.

If Schiit can offer 8w in their Mjolnir, Airist Audio should be trying to at least match that, and considering the price difference between them, this would be justified and would raise the price to performance value in the final score of the product.  Burson should do this as well, so it isn’t really a fault of Airist Audio in that regard.

Justified Pricing

I really enjoyed this amp, but I am not sure if the price tag of $1,999 is justified for a pure amplifier with no DAC inside.  I hate seeing products this expensive when there are so many budget to mid-tier titans that offer a ton more features.

Considering that I’d hunted for years for an amplifier this clean and with a soft impact, large stage and plentiful everything to be paired with an HD800…something to make the HD800 less of a harsh experience and more enjoyable to me…I’d throw twenty $100 bills at Airist for this amp and not think twice about it

Mad respect to a brand new team willing to sell a $1,999 amplifier as their first project and do a good job with it.  That takes real guts and a drive to know exactly what they want to offer, so I fully expect this company to try to do an even better job in the near future and maybe fix just a few trivial features inside this amplifier.

My advice is to pick one of the inputs and stick with it, XLR or RCA only.  Or, offer more as the Cavalli Liquid Carbon does with a ton of inputs that include 3.5mm and balanced ins and outs.  At this price, it should be a given that it would offer a well-rounded selection.  Also, bump up the wattage to 8watt or better.  Give the community a good reason to want to use this amp with needy planar headphones.  At $1999, more options need to be available.

Technical Specifications

Frequency Response 20 Hz – 20 kHz +- 0.05 dB
1 Hz – 101 kHz +- 0.2 dB
Phase Response 20 Hz – 20 kHz +- 2 degrees
Noise Floor < -100dBm (0.1 picowatts)
THD+N @ 1kHz <0.0015%`
Dynamic Range ≥ 130 dB, 20 Hz-20 kHz A-weighted
Signal to Noise Ratio (SNR) @ 1kHz 132 dB A-weighted
Crosstalk < -80 dB, 20 Hz-20 kHz
Gain 12.5 (22db)
Output Power 5W at 32 Ohm
Inputs 1 pair RCA, 1 pair XLR
Outputs 1 low impedance 6.3 mm, 1 high impedance 6.3 mm
Power Consumption 65W max, 10W nominal
Size W13″(33cm) X D11″(28cm) X H3.9″(8.5)
Net Weight 14 lbs (6.4kg)
Shipping Size W17.3″ (44cm) X D17.1″(43cm) X H8.7″(22cm)

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