Reviews by dmhenley


100+ Head-Fier
Pros: Exemplary build and sound quality. New-retro style. Gorgeous hand finished casework.
Cons: None - only limitations - those who need more than a couple watts to drive certain headphones may not find an ideal pairing here.
Many of us pursuing the hifi hobby are moving toward the goal of finding a reference component that we can live with long term. While we will also continue to try new gear - of course - it's great to have a core system that represents our personal playback ideals. While those ideals vary for each of us, we share in common the desire to find our musical match.

I have cycled through several amps over the years - both solid state and tube - and quickly found that low watt tube amps and sensitive speakers/headphones are where I want to live. It's safe to say I have found my reference amplifier. Prices (depending on specs) for the Euphoria Stereo amplifiers will run near US$3000.

I will be objective in my report, but I admit I am biased. This amp checks off most of the boxes on my list of audio wants. Context: I am a drummer, and my experience playing live acoustically is often my reference for great sound.

Last year, I came across Matt Formanek, owner/designer/builder at Toolshed Amps, during an online search for tube amp builders. A music lover, ex-hifi shop proprietor, cabinet builder and very cool guy - Matt started Toolshed in 2014. He brings his deep skill set, broad experience and artists spirit to bear on a small line of low watt tube amplifiers. I'll defer to Matt in regard to his background with a Q&A I posted on my blog some months ago -

Euphoria Stereo 45

On to the focus of this review: the Euphoria Stereo 45 is a direct heated triode circuit designed around the revered 45 tube. E180F/D3A tubes are assigned to preamp duty, with the GZ37 on rectification. I asked that my amp be built as an integrated, with both headphone and speaker outputs. Point to point wiring, high quality components, and attention to detail all lend to the exemplary build quality. Matt builds and finishes the custom wood bases, handles the cutting and etching on the aluminum plates, and wires the amps himself. My amp got 100 hours of burn-in prior to shipping. See the photos for more on the overall build quality.


I primarily listen to cd quality streams via Tidal, and use Roon as my interface. I also listen to vinyl, but for our purposes am focusing on streaming audio. My source is a Win10 pc, and I run a microRendu (w/LPS1 psu) into the Schitt Yggdrasil dac (Anticables USB cable), which feeds the Euphoria 45. All components are powered by a PS Audio Power Plant Premier. My primary headphones are the Audioquest Nighthawks with a Double Helix cable. I used the brand new (40 hours on them) Sophia Electric mesh 45's and Mullard E180F's for this report.

Being a very low output design, it does not generate a ton of heat. It is hot to the touch, but doesn't raise the temperature in my office like some other amps have. It's a full size component - I wouldn't call it a desktop amp - but that's not to say you couldn't set it on one. The amp weighs in around 23 lbs. There are old school switches for power, impedance (8ohm and 16ohm) and headphone/speaker selection. There's a rotary switch on the front for input selection, just to the left of the 1/4" headphone jack.

This is an early review - I'm in my first week with the Euphoria 45 - so, will be following up with updates as the weeks and months pass. We can talk about stability and my evolving impressions later.

Overall Sonics

First thing - the amp is very quiet - a prime concern for today's headphone enthusiast. When using my NOS RCA Radiotron 45's, the background is quiet. This is not the virtual vacuum of a digital tomb quiet. No. If you're after that, then this may not be the amp for you. The Sophia Electric mesh 45's do hum a bit, but it's not enough to keep me from using them. I also listen via my vintage Altec Lansing speakers, where the hum is nearly inaudible from my chair. But, this is specific to the tubes - the amp itself is quiet. These circuits are chosen for their immediacy, tonal 'rightness', dynamics and transparency. Component changes will affect the overall character. And tube selection will too - part of the fun with tube amps. 45's are known for very low distortion, inner detail, extended bandwidth and killer tone. I've found this to be true, and will add that rolling these power tubes will offer some variance in these attributes. So, like most tube amps, within the overall presentation, you can 'tune' the amp with tube changes.

Incredibly musical, dynamic and engaging. The amp is quite revealing and will present any perceived flaws in the recording and/or your upstream components performance. That said, these things are well balanced. This is not a tubey tube. Heh. Not overly warm or bloated. Linear, but not lean.There is an ease to the sound, despite the detailed nature - one hallmark of great components.

I look to be gripped by the music, and am less interested in the specific hifi attributes. Most of the time.

Again, the amp is revealing, but not bright. The stage is wider than anything I've heard with the Nighthawks - which are known for a close/intimate presentation. There's more room for each voice or instrument to be fully rendered, but not overtly. If I think of the stage in a globe, but as a balloon, it's like we've injected more air into it. Layering and depth are ideal for me. I don't feel that the amp is exaggerating this, but the tremendous insight it provides brings me into that space.

Tone! Oh man...pianos sound right - notes are balanced between the hammer attack and weight and a blend of the overall instruments sound. Instruments in general have weight, and so feel more real. I imagine it as gravity - the drums are stable in the stage and feel like they're moving air - as if you were standing in the room with them. Combining that luscious tone with the transparency, we get all the harmonic complexities of acoustic instruments played by people in a shared space. If that's in fact how it was recorded. Crucial in creating the illusion of being there. Voices have intense presence, and I can experience the singers subtle inflections.

Speaking of weight, the low end is balanced as well as I could want. Deep, solid bass notes, complemented by an open mid-range. No mud. In fact, I think the 45's linearity is an excellent match for the Nighthawks. One complaint many have about them is a certain bloom in the lower mids/upper bass. I'm not finding this to be an issue now.

I consider the Euphoria Stereo 45 to be an heirloom quality amp. It delivers world class performance and a build quality to match. In concert with my Yggdrasil, the Euphoria 45 translates the energy of a performance to me - this is among the highest praise I can give.

The style may not be for everyone. For those who dig the updated retro design, and are looking for low watt tube power will not be disappointed.

Thanks for listening.


  • TSA_E451.jpg
    3.3 MB · Views: 0
  • TSA_E45_2.jpg
    3 MB · Views: 0
  • E45_front1.jpg
    1.7 MB · Views: 0
  • IMG_20170813_215801 (2).jpg
    IMG_20170813_215801 (2).jpg
    2.3 MB · Views: 0
  • IMG_20170812_160308 (2).jpg
    IMG_20170812_160308 (2).jpg
    3.2 MB · Views: 0
  • E45_Unbox1.jpg
    4.8 MB · Views: 0
Alex Kitic
Toolshed amps bear a curious resemblance to my projects:

RH2A3/45 - very specific for the ability to allow use of 2A3 and 45 seamlessly, with a load of 5k for the 45, which is also not a usual feature.


with the driver section (EF86) of another project, the RH84 PPE:

The ”author’s” own schematics are not published or available, but we did exchange emails in the past where I provided help and advice as to any DIYer, before any of Toolshed amps came to be.

Reviews don‘t mention the schematics details, but the “author” posts on forums Some of my (well known) schematics as if his own... that got me checking what is going on.

Check-out my blog (just google ”RH Amplifiers”) and get an opinion about the fairness of selling someone else’s projects as one’s own - just because people post perfectly working painstakingly designed and optimized schematics for the benefit of DIYers.
Alex Kitic
Addendum - the RH84 PPE simulation, for those interested (longest post is 1000 characters)


100+ Head-Fier
Pros: Warm, natural sound. Comfort and a classy style. Fully serviceable!
Cons: Not as natural and linear as I'd like.
I signed on for Meze Audio's Head-Fi tour a few months back, and their latest product arrived for a short visit this month. The Meze 99 Neo (US$249) headphones. Thanks so much to Meze for including me in the tour.

This is my first time sitting down with any of their products, though I did read some reviews of both the Classics and the Neo in advance. I will keep this short, as there are many exhaustive reports already available online. I'll try to get to what I think are the key characteristics before you grow tired of me.


Photo courtesy of Meze Audio

I love the look of the 99 Neo. The build quality is impressive, and the design is classy. The electroplated zinc alloy hardware combined with the plastic black cups and memory foam ear pads makes for a sleek look. The fact that all parts are serviceable is outstanding. Not many out there today that can make the same claim.

The hard shell carrying case for the 'phones, and the smaller accessory case are high quality. Both have a texture that is pleasing to touch. I assume the 99 Neo are aimed at users who are on the go. I did not have an opportunity to step out with the Neo.


The 99 Neo are 3oz. lighter than my main comparison for this report - the Audioquest Nighthawks. The Nighthawk's ear cups are slightly larger and shaped differently, so for my large melon, they're more comfortable. I've big ears too, so while the 99 Neo are quite comfortable, I've got more room in the Nighthawks stock pads.

Again, the 99 Neo are very comfortable headphones. I had no problem with them over longer sessions. Of course, the closed design is going to be warmer than an open one. Out here in the desert, it is something to consider. Of course, for their target audience, the closed back may not be negotiable.

Meze provide two cables - the short and the long. I used the longer cable the entire time, and appreciate having enough length to move around my office. My DHC cables are short, and keep me tethered to my source.


Both headphones have similar impedance - 26db (99 Neo) vs 25db (Nighthawks). The Neo is rated at 103db sensitivity. That's 4db higher than the Nighthawk. Wow. I'm sticking with my AQ Dragonfly Red paired with an AQ Jitterbug for power. Streaming cd quality tracks via Tidal the entire session. I listened with both a PC source and Android phone.

These are great sounding headphones. And fun. The bumped mid-bass, or bloom, is readily apparent. That bloom - and, maybe a dip in the upper mid-range - in combination result in a somewhat warm and close presentation. Intimate. Cymbals lack some of the overtones that the Nighthawks present. It's quite subtle, and overall they sound linear and natural. The 99 Neo are an energetic headphone. Dynamic, and driving. Punchy. At times, the shove in the low end brought to mind two channel speakers.

Based on my short time when them, I feel it's less about high frequency extension, and more about the slightly lifted low frequencies - this warmer, shadier tone. I really enjoy the sound. To my ears they are slightly less linear and natural in comparison to the Nighthawks with my Double Helix cable. You know, I would've have tried the DHC cable with the Neo, but the connectors did not fit. The Nighthawks are more relaxed, being a more open design.


Fiona Apple's voice on "The Idler Wheel..." illustrates my earlier point. Less head, and a tiny bit more throat and chest in vocals. And, cymbals lose some of their overtones. Acoustic drum stick attack and body are highlighted with the overtones slightly diminished. Pianos and other assorted keys on this record reflect this same downward shift of the stage. Again, this is subtle, and not necessarily a mark against the Neo. Just my own observations set down here for your consideration.

As for isolation - I don't have another closed pair available for a comparison. The 99 Neo seemed to isolate well. I was not able to test this in an office or elsewhere it might be needed.

The 99 Neo are a great sounding and stylish headphone. They were easily driven by my OnePlus3 phone streaming Tidal HiFi. Likewise with my pc in combo with the Audioquest Dragonfly Red. I wanted more time to test a more powerful amps affect on these sensitive phones. I am currently without my usual tube amps, so have stuck with the portable rig for the entire session. I think this may be more relevant for folks who are considering the Neo, anyway.

So, they are easy to drive, have a warm, natural voice, and are really comfortable. I think you can't go wrong if you are looking for a closed back and portable headphone in this price range. Add to this that they are stylish and fully serviceable, and they begin to compete outside this range. In a world of primarily recyclable products, one that has a higher probability of outliving me is very attractive.

In my reading I found that Meze has a devoted following, and I now know why. The 99 Neo are an excellent product.

Thanks for listening.
  • Like
Reactions: Bansaku


100+ Head-Fier
Pros: Solid build. Affordable. Great sound quality. Tube rolling! Will drive both headphones and sensitive speakers
Cons: Only that I'd want another input.
Ampsandsound are an amplifier and loudspeaker builder out of Southern California. I discovered Justin Weber and team through Head-Fi, when reports of their Kenzie headphone amps appeared. Since then, I've kept an eye out, and even considered their 2 channel amps for my system. The Bigger Ben was interesting, for sure...until I caught word of the Mogwai.
The Mogwai (US$1850) is a single-ended class A tube amp, that employs 2 (one per channel) EL34, 6L6GC tube, or one the many variants available (KT66, KT77, 6CA7, KT88, 6550). The input is handled by a single 6SL7. This point had me jazzed - I've plenty of these power tubes around from previous amps, and was actually daydreaming about how great it'd be to have an affordable low watt, single-ended amp I could work with. After a couple calls and some deliberation I committed. I was able to grab it when they were offering the show discount.
Justin Weber was quick to respond to all inquiries, and happy to discuss his products. In addition, he delivered the amp before his original target date. The excellent service is much appreciated and deserves mention.
Note: Justin does recommend that you do not run both speaker wire and headphones simultaneously. This is due to the fact that there is no voltage divider network, and both outputs are wired directly to the transformer. You will get the best performance this way. I assume for most, this isn't an issue as the Mogwai will play the role of headphone amp most of the time.

The speaker binding posts, headphone jack are high quality - everything you might touch feels solidly built. With the Audioquest Nighthawks, there is no noise apparent when the volume is set at my usual level (roughly 9 o'clock), and no music is playing. The Mogwai runs quiet. Of course, as I turn the dial up toward 12 o'clock the noise becomes apparent - sensitive 'phones.
For all listening, I used a Sylvania 6SL7 V-229 on input duty. My source is the Clearaudio Concept MM 'table and the phono pre is the Parks Audio Budgie.


I had three sets of power tubes I wanted to try out. With the KT66 installed, the sound was spacious. I heard a larger stage with remarkable depth and layering. Overall, a I heard a balanced sound across the spectrum, though they are lacking in bass weight and presence. I've read these Gold Lion tubes take hundreds of hours to settle in - maybe the low end will improve over time. Definitely less mid-forward compared to the 6CA7-Z, but they projected a holographic stage. Paired with the Audioquest Nighthawks, the sound was dynamic and addicting. The Mogwai, Gold Lion KT66 and Nighthawks make good company.
Next, I tried my Gold Lion KT77s. These are great tubes, and sounded fantastic in this setup.
Currently, my favorite tube in this setup is the PSVane 6CA7-Z treasure tube. It delivers luxurious mid-range, extension on both ends of the spectrum, and all the nuance I want. It's a very engaging and commanding sound. A ton of drive and grunt - even though I was optimistic, I wasn't expecting such killer performance.
Ok, so some detail around the Mogwai's performance driving my Tekton Lore (98db) floorstanders:
On Allison Miller's latest release with her band, Boom Tic Boom, I'm hearing more of the room even with the luscious mid-range. Kirk Knuffke's cornet has plenty of both breath and body. The kick drum moves air like you'd expect and the upright bass has a ton of woody tone and blossom in the lower reaches.
As for electronic music:
The second track on James Blake's record, Overgrown, has some deep reaching synth bass notes. The Mogwai with the 6CA7-Z delivered on this track with great extension, though limited power and grip. Of course, you're not gonna get full control over those drivers with this amp, but it delivers very satisfying bass. It is tuneful and with plenty of texture - that's also the 6CA7-Z's. The quality of bass in the more common bass guitar range - both acoustic and electric - is excellent. I've been told some prefer KT88 tubes for their linearity and exemplary low end performance. While, I don't have any on hand, I'll eventually give it a go.
Overall, the Mogwai's circuit is transparent - all tube swaps were easily apparent - and, this is certainly one of it's strengths. It's also responsive to tube upgrades. You can roll (affordably!) to your heart's content. This was key for me. I'm currently limited to the Nighthawks for testing headphone performance. In this area, the Mogwai delivered quiet performance, musical and commanding sound, and with tons of headroom. I hope to have another pair of headphones to try out soon.
This is a heck of a lot of amp for the money.
If you want a stout, quiet tube headphone amp, and dig rolling, then the Mogwai is a great choice.

  • Like
Reactions: Aslshark
Sonic Defender
Sonic Defender
Nice review, thanks. Just purchased a Flac download of a Boom Tic Boom album, sadly from 2010 so not the most recent work, but the only album of this band on
A sweet review, seems like a cool amp for people getting into world of tube rolling.


100+ Head-Fier
Pros: Ultra Quiet, Linear, Musical, Resolving and Authoritative
Cons: Subtle sheen in high freqs, Limited to SE Outputs, Output jack quality could be better
Thank you to Airist Audio for adding my stop to the current tour.

Airist Audio ( is a young company now jumping into the personal audio market with their first piece of gear - the Heron 5 (US$1999) headphone amplifier. The Heron 5 is a solid state amp aimed directly at the higher end. According to their site, both its circuits and cosmetic designs reflect Airists principles - those of purity and subtlety.



In the 7 days I've spent with the Heron 5, I have found its many qualities are closely aligned with Airists stated design principles.

Temporarily stacked on the Schiit Gungnir, for reference.


Design (
The Heron 5s appearance is understated. Modern minimalism. The matte silver-grey finish of the top, front and sides of the chassis is uninterrupted by any mounting hardware. The only visible screws (hex) are on the bottom and back plates. Power button (left) and volume knob (right) sit opposite each other on the front plate. The volume knobs front plate is black and the indicator glows red when the amp is operating. Though only single-ended outputs are provided (not an issue for me currently, since I'm using the stock Nighthawk cable), there are separate High and Low impedance connections.
The only other cosmetic addition is the Airist logo stamped above the power button.
On the back we find one pair each of RCA and balanced inputs, with a switch for input selection. A standard IEC jack sits on the right end, opposite the inputs.

Heron 5 rear view

The internal design is focused on signal purity, with discrete circuits for amplification and power. The signal path includes silver wire and no coupling capacitors or DC servo. A custom made power transformer and stepped attenuators are key components of Airists design. For additional technical details and specifications, use the link above.

Quick note on operation:
The amp has a soft start function, so when powered on, you'll wait for 5 seconds before it's ready to rock. The volume knobs indicator light flashes until the amp is ready.


I'm running a dedicated Win10 machine with multiple tweaks to improve audio quality (Fidelizer among them), Tidal/Roon server as my software, with the Roon Android app as controller. USB (Audioquest cables) out to a Schiit Wyrd which in turn feeds my Schiit Gungnir multibit dac. I have used the single-ended (Anti-cables) connections on the Heron 5 for the entire week. Utilizing the Gungnirs multiple outputs, I was able to quickly switch between the Heron 5 and my Bottlehead SET amp. Clearly, not apples to apples. Yes...but, perspective was needed. Finally, I used my Audioquest Nighthawks (25ohm) 99% of the time, connecting them via the high impedance output jack. AKG Q701's made a brief appearance - again - this provided much needed perspective.

I admit, living solely with tube amps the past couple years, I had in mind in advance how the Heron 5 would perform.
Happily, I concede my expectations were only half right. Er, less than half.


For those who're done with me now...If I was to compress my thoughts into one line:
The Heron 5 is musical, quiet, powerful, refined (silver-tongued), highly resolving and smooth in its presentation.
I have logged about 40-50 hours with the Heron 5, so while I think we've not hit the recommended (per Airists manual) 72+hours of 

break in, allowing the amp to reach optimum performance, I can safely say I am familiar with its qualities. 
Limited time with the amp drove me to focus my listening sessions. I built a playlist (4 hours running) covering a wide array of styles and production quality.
Jazz, Rock, Hip hop, Electronic, Classical, Americana - my tastes vary.







The Heron 5 is dead quiet - both the signal and operating ambient noise are imperceptible.
The exception would be when turning the volume up (no music playing) all the way - there was hiss in the last 3 clicks.
I ran the Nighthawks somewhere between 10 and 11 o'clock, depending on source volume.


As expected, the very low noise floor allowed micro detail to float up out of that quiet space. Not something you get with  my SET amp and 25ohm headphones. Immersion is the result.

The amps ability to set the stage is remarkable. Rock solid, defined though not to the detriment of overall coherence. As time passed I chose more complex and dense recordings to confirm my impressions. On Talk Talks album Spirit of Eden, the track Inheritance is very quiet, warm, atmospheric and full of subtle musical cues. All were anchored in the recorded space, and layered in way that lent new perspective on the song.

No slouch in the tone department, the Heron 5 delivers rich tonal colors balanced by a clear mid-range.
Woodwinds have body and harmonic texture. Snare drums (initially a tad papery) have snap and body. Whock. Not whack. When appropriate, of course.

Well-recorded pianos are satisfying - the complex overtones are presented beautifully.
Nils Frahms 'Solo' record - the track Chant - the oscillation of the bass piano strings is palpable. Hammer attack is tactile.

Vocals are rich with their natural overtones. Sibilance is presented, if the recording delivers it, and I do note a touch of silvery sheen at times. This is apparent at times with cymbals too - a subtle unnatural sheen. I do feel this has lessened as the hours pass. In comparison, the SET amp delivers a touch more dimension, air, and natural tone. In trade, it's less linear and far-reaching in the frequency extremes. No surprise. These are subtle differences.

Shabazz Palaces - Forerunner Foray is a cloudy experimental hip hop track. A lot happening here, and the amp handles it with commanding bass (depth and control), clear synth textures and sparkling high end. Definitely some harshness on the backing vocals, and the Heron doesn't mask this.

Kirk Knuffke: Arms and Hands - on the track Umbrella, we have bowed upright, trumpet, and cymbals and toms played with mallets. Cymbals open up and bloom as they should. Hats have tone - not just snick. The air apparent in the space. A great example of the balanced, linear performance in the mids and upper frequencies.

Nothing's latest record isn't a great recording, but I dig the heavy shoegaze style. On the title track, guitars are well represented, and the Heron 5 manages the dense layers of distortion, cymbals and heavily affected vocals with ease. This is one loud band, and confirms the Heron 5s ability to rock balls.

Shudder to Think: Pony Express Record - X-French Tee Shirt
This is a great, though typically clinical rock recording from the mid 1990's.
The Heron 5 anchors the tune with solid kick drum and guitars.

All Them Witches: Dying Surfer Meets His Maker -
This swampy, heavy psychedelic rock bands dense guitar layers are laid bare, and the drums (over-compressed) punch and kick at chest level.
This record is muddied by lesser gear. Not so here.

The Heron 5 is a highly musical, resolving and authoritative amplifier. Staging is rock solid and balanced with a coherent delivery.
Quiet, and smooth - it can deliver the micro detail when called for, and the tone, texture and dynamics make for an engaging listen.

I am curious as to how well the amp pairs with high impedance headphones. And, how it compares to other solid state amps of similar quality.
I'm hoping some others on the tour will provide that insight.







Not sure if this is the amp for you? 
If you're a solid state music lover, looking for linearity and purity, and US$2000 is in your range, the Heron 5 is absolutely worth a spin.
I believe Airist Audio have succeeded in making the amp they set out to make - well done.

Kind of curious.... Why did decide to use the high impedance input for the Nighthawks ? It is encouraging to hear you were able to listen at a 10 or 11 o' Clock volume setting with a 25 ohm headphone. I would think that would indicate that with a 300 ohm headphone that there is a nice broad usable volume control range available !

I've had to resort to using In-line Attentuators (Rothwell) with my "Hybrid"12AX7 Tube Headphone Amp to get the type of dead silent dynamically rich perfomance I like with a full volume control range of use.

If ever I come across a "spare" $2k , I'll have to give this amp a listen as I'm not a fan of "Tube Rolling" (different tubes do make differences, but they end up being hit or miss as to their worth sometimes; crossing my fingers on the set I have coming in this week !)
I'm looking forward to my turn. Hopefully the European Heron 5 will start moving soon. Great review!
Hey knowhatimean -
The label on the Heron 5s output refers to the outputs impedance and not the headphones.