Cayin Soul 170HA KT170 Vacuum Tube Headphone/Speaker Amplifier

Flagship headphone gear has really been taken up a notch or two in the last couple of years. The concept of continuous escalation certainly applies. I’d argue that it’s not enough, nor is it just about making functional and good sounding gear, it’s now become about making them more and more beautiful, maybe even required even. They almost have to because the market keeps getting more and more saturated. Lately, it seems like companies are positioning themselves to create flagships that are bold and create a statement. Cayin’s release of the Soul 170HA is aiming to do just that and I adamantly believe they succeeded.

If you’ve ever spent much time in the Cayin Soul 170HA forum thread, it will not come as a surprise that I love this flagship amplifier. When I first heard it at CanJam So Cal 2024, I instantly was enamored and knew I had to listen to it numerous times within those two days just to confirm what I was hearing. Level-setting a little bit— I did not go to CanJam So Cal looking for a new tube amp, in fact, I was more specifically looking for a solid state amp that would be able to compliment my Woo Audio WA23 Luna. Cayin had announced the Soul 170HA a little bit before CanJam, so it was indeed on my radar to check out. On paper, it looked like a very interesting proposition with the flexibility that it offered. Plus, it looked good and that always scores bonus points and unabashedly a requirement in my book. So, if I love the amplifier, what can I say about it and why even do a review? It ought to get more exposure and I am hopeful that talking about it will do that. Even though I love it, I have a lot to say about it and not all of it is good. Before I get into all of that, lets just go through some of the details of the amplifier first.



The Cayin Soul is an amplifier that is made to drive various transducers. Its primary function seems to be based around driving headphones, where the front houses a ¼ inch output, a 4-pin XLR output, and a 4.4mm output, designed with IEM use in mind. However, it also has speaker taps on the back. For this review, I will not be evaluating the speaker capability of the amplifier. I may in the future, but presently, I do not use speakers in my office setup. The Cayin Soul 170HA has a couple of toggle switches on the front, one that switches between the three headphone outputs, 1/4inch, 4.4mm, 4-pin XLR. The other toggle switch is the impedance switch, Low (8-64 Ohm), Medium (65-250 Ohm), and High (251-600 Ohm), to cover your various headphone impedance. The amplifier is single-ended by design, so the XLR inputs and outputs are more for convenience purposes.

On the top front of the unit, there’s a VU meter illuminated in orange that wonderfully matches the glow of the tubes that flank the VU meter and other toggle switches. The switches are an RCA/XLR input selector, speaker/headphone output selector, triode/ultra linear mode selector, and finally a dynamic/soft selector. The first two are straight forward, but the other two are the more fascinating switches. I won’t go into too much detail about it, but you can read about those in Cayin’s own literature. Though, I will just say that the TR/UL mode switch gets a lot of use.

The basic gist of this switch is switching the KT170 tube to connect directly to the anode in triode mode, where the ultra linear mode taps the KT170 tubes to the output transformers, which provides higher voltage. What this does to the sound, I will take this verbatim from Cayin’s website: Triode mode “Tendering, smooth and elegant, holography with sharp image, suitable for vocals, string music, and mid-range focused genre” and Ultralinear mode “Open, bold, with great momentum, soundstage will open up, suitable for orchestral, OST, and music with a wide dynamic range. I would say that the general descriptions are pretty accurate and I will go back and forth between the two modes, depending on the headphones that I am using, the music I am listening to, and even what mood I am particularly feeling. It makes a pretty significant change to the sound presentation of the amplifier. The dynamic and soft toggle switch is much less significant and more subtle than anything. From Cayin’s literature: Dynamic is “Dense, fast and authoritative, prominent dynamic with contrast. Forceful and exciting quality.” Whereas Soft is “Relaxing, delicate and peaceful, reveal low-level details. Engaging and involving quality.” I’ll be honest, this toggle gets used much less. While I hear differences, especially in the midrange detail and energy, it’s not night and day.

Power output-wise, the Soul 170HA is a monster and capable of driving every headphone that I’ve tried on it and with ease. Thanks to the KT170 power tubes, the rated power output breakdown is as follows: 4-pin XLR outputs 12-18WPC, ¼ inch outputs 7-17WPC, and the 4.4mm outputs 2-4WPC. The 4.4mm works extremely well for IEMs or if you want to use a 4.4mm for your over ears. I will say that the noise floor isn’t completely quiet. Sensitive IEMs that I used, like Forté Ears’ Macbeth did exhibit a bit of hiss and tube noise. Putting the amp into triode mode does lower the noise floor, but realistically if you are looking for a black background for IEM usage, the Soul 170HA wouldn’t be my first choice. Using the Astell&Kern x Empire Ears Novus IEM, there was very, very little noise. That said, the amount of authority and power that this amp drives the IEMs to is extremely impressive. Once your listening to music, it’s almost a moot point anyway.



How Does It Sound

Sonic characteristics of the Soul 170HA, I would classify as a warm, neutral tuned without sacrifice of details. It’s a weighty presentation, but it’s not gooey or wet sounding. Especially in ultralinear mode, it’s highly detailed, has a big sound stage, has a rich midrange, and a hefty, authoritative bass that digs deep into the sub-bass region. You can further color the sound with a flick of a switch or two, namely switching from ultralinear mode to triode mode. With triode mode, the midrange becomes a little bit more prominent and musical sounding, adding a little bit more holography and just a bit more of what you would expect from a tube amplifier. Triode is proper tubey goodness while not getting too soupy. Dynamic range is lessened, but it’s far from lacking even detail or bass authority.

You can additionally customize its sonic characteristics with different tube options, too. Options to swap the GZ34 rectifier tubes or the 6SN7 driver tubes give you a lot of flexibility to shape the sound to your own personal preference. Unfortunately, the power tubes are not rollable, so good or bad, you are stuck with the Tung-Sol KT170s (for now). I spent a couple weeks listening to the amplifier in stock configuration with the JJ GZ34 and JJ 6SN7 tubes, but my current set consists of Mullard GZ34 and Apos Ray 6SN7 Reserve tubes.

For headphones that I’ve evaluated on the Cayin Soul 170HA, most of my listening impressions are on the RAAL 1995 Immanis, ZMF Atrium Open, and Meze Empyrean II. IEMs that I’ve listened to here at home include the Forte Ears Macbeth, Astell&Kern x Empire Ear Novus, FatFreq x HBB Deuce, and 64Audio A12t. Additionally, at CanJam So Cal, I also listened to the following on this Amplifier: Modhouse Tungsten DS, Caldera Closed, Atrium Closed, Susvara OG, and Susvara Unveiled. Mind you, any listening done at CanJam with those headphones was not extensive and I won’t be able to comment too much about them individually. I will just say that the Cayin Soul was able to drive them all pretty effortlessly and sounded great with each of them.

Treble

Soul 170HA has a little bit of treble roll off. It’s a warmer sound, but it’s not really dark or veiled. I still get a good amount of sparkle and air in the presentation. High frequency detail is still present and easily placeable, especially in ultralinear mode. Leading edges in attack are sharper in this mode. It certainly takes some of the edge off of some of the bite that some tracks might have. Tracks like “Hit the Lights” by Bensley or “Mirapolis” by Rone & Johannes Brecht. Despite its warmer tonality the amp is quite capable in overall resolution that it doesn’t feel smoothed over. This is certainly the case when I listen to the ZMF Atrium on the Cayin. Putting the amp into UL mode and medium or high impedence and the Atrium are just about as energetic as I’ve ever heard them in the treble. It’s not fatiguing, but there’s a lot of air and it’s the biggest I’ve heard them sound.

Putting the amp into triode mode rounds the treble even more, reducing the dynamism and edge a little bit further. It gives the amp a more euphoric signature in the treble. You do sacrifice a little bit of precision with a little bit more of a rounded tone in the treble, but air is still present. The lateral width of the soundstage and the sparkle does shrink a little bit in triode mode. I think this is actually helpful specifically for a headphone like the Meze Empyrean II. I find that headphone has a lot of lateral width, but forward depth is not as big. The triode mode makes the oblong soundstage of that headphone more circular. I also think there’s a little bit more lower treble energy in the Empy II that benefits pretty significantly from the sonic characteristic of the Cayin.

With the RAAL Immanis, I end up favoring using the ultralinear mode more, though not exclusively. There is a certain magic that I find with his pairing in the upper frequencies. Treble sparkles and is highly resolving of micro details and air. The Immanis sounds quite expansive. Upper harmonics and overtones prevail while listening through the Immanis. In live recordings especially, the size of some of the halls, notes and sound echoing through space is more tangible than I’ve experienced before with this pairing. Conversely, studio recordings have a reduced sense of the additional overtones and harmonics and sound unsurprisingly smaller and more “room-treated.” No other headphone pairing with the Cayin was able to present that size perception better.

I really like the treble character of this amp. It’s one of the many appealing aspects of the amp. It is never fatiguing to my ears. Detail is present, but the treble still exhibits weight and texture. Despite the coloration, it is still surprisingly revealing. I do feel like I got a bit of treble energy extension and detail with the Ray 6SN7 Reserve, too. Overall, though this amplifier isn’t going to be for those who are looking for neutrality, incisiveness, and a colorless presentation.



Midrange

Flexibility is the name of the game in the midrange. I think the midrange is really lovely on the Soul, though it’s bested by other tube amps, like the Woo Audio WA23 Luna. That amp I think has one of the best midranges in the market. The Cayin in triode mode though, has a lushness and euphoric nature that the midrange takes on. The tonality brings it closer to the WA23 and I think with the right tube combination, it can close the gap even further. Holography certainly is improved with triode mode, too. The shift in tonality just brings a bit more attention to the midrange. It doesn’t simply push mids forward making them intimate. No, in fact, they just get deeper in the sound stage in triode mode. This has been a really good choice for my chamber music, both vocal and instrumental. The piece, “On the Nature of Daylight” by Max Richter is a great example of this. The cellos sound lush and tangible. My a capella music, too, like Home Free’s cover of Johnny Cash’s “Ring of Fire.” The all-male group has some really lovely harmonies that in triode just sound a little bit sweeter.

Where I end up preferring ultralinear mode’s midrange is on big orchestral pieces or big band albums and songs. MIchael Buble’s early albums, “Call Me Irresponsible” & “It’s Time” retain its grandiose scale and I feel that instrument separation is better. The larger soundstage in ultralinear mode just help place more space between everything. Michael’s vocals are very squarely in the middle, but the band’s instruments surround him, both on the sides and behind him. Hans Zimmer’s score on “The Dark Knight Rises” album also has the same effect.

An aspect that I really like about the Soul’s midrange is its inherent body. It’s not thick per-se, where thick mids quite often can feel overly hefty. Especially in vocals it can just sound excessively throaty. The note weight just feels very well balanced. It’s well textured and also not overly emphasized. I find both male and female vocals just sound engaging on the Cayin Soul. With the right headphones, mids are also very well articulated, exhibiting very, very good instrument separation. Vocals and various instruments retain each of their individual character and never feel congested.

Bass

Powerful. Controlled. Articulate. Remarkable. I don’t profess myself to be a bass head, but I still need good bass to have a well-rounded, engaging listen. The Cayin Soul provides that better than any other tube amp I’ve tried. Envy was close, but a little bit thicker in the bass presentation and the sub-bass is just a little bit less prominent. That’s when comparing ultralinear mode to the Envy. I think the triode mode actually brings it more in line with what I remember from the Envy’s bass, a little bit more rounded and a bit less sub bass energy.

With the ZMF Atrium Open, I have never heard the headphone become more aggressive in the bass than I have with the Cayin. Ultralinear mode and high impedence, the Atrium comes alive and energetic. There’s a level of punch that and slam that the Atriums took on that I’ve not previously experienced. Every track that I’ve tried simply just attacks and hard. It’s not pillowy or bloomy, in fact, I find it more articulate, while more dynamic. It’s quite something and makes me interested in seeing what the Atrium Closed and the Caldera Closed are capable of on the Soul. I’ve heard some say that it can be too much of a good thing, but I’m here to say otherwise. Granted, you can tone down the energy with a flick of one or two switches, putting it in triode mode and/or lowering the impedence switch down. It’s still impressive even with these settings.

With IEMs through the 4.4mm connection, bass is equally improved through the Soul. It is more powerful and more prominent than any portable solution that I’ve heard to date. A&K x EE Novus growls aggressively with control and authority while reaching sub frequencies that will massage your brain. I’ve never felt the inside of my skull vibrate so prominently. The very same is the case with the FatFreq Deuce. These two sets would please the bassiests of bass heads on the Cayin Soul.

Bass on the Immanis, I’ll lead with this… this is one of the reasons why I was so excited about the Cayin when I first heard it at CanJam in the Bloom Audio room. I vividly remember the bass that I had gotten with the WA23 paired with the Immanis and the Cayin did all of what the WA23 did with the bass, but just became punchier, harder hitting, and was more textured, which was what surprised me most. As I tried tracks like, “Give Life Back to Music” by Daft Punk, it was immediately apparent that the Cayin elevated the bass experience. Again, it wasn’t really that the bass became thicker and more bloomy, rather it just articulated more and had more weight. It didn’t just have more weight, but the control it has with the Immanis at the same time.

With the Meze Empyrean II, I also found the bass to be the best I’ve heard them sound. Meze has a mid-bass boost and the Cayin doesn’t overly emphasize it further, making it bloomy. The Empyrean II are rolled out a decent amount in the sub-bass region and the Cayin I felt brought a little bit of that back. It’s not a significant change or automatically make it a linear headphone in the bass, but it did give it a little bit more energy down low.



Soundstage

I touched on this earlier, but wanted to revisit this on its own. As I said earlier, depending on the mode you choose, you get larger-sized sound stage (ultralinear) or you get a slightly narrower image, but you gain forward depth (triode). Overall, I find that both modes have their use cases, but realistically, the soundstage is fairly large in its stock configuration. Adding the Apos Ray 6SN7 Reserves did expand the soundstage a decent amount, too. So depending on the tubes you roll, you can get even bigger stage (or smaller, if you choose). However, the Atriums certainly sounded the largest that I’ve experienced on the Soul. As I mentioned with the Meze Empyrean II, I preferred the triode mode for it’s reduced lateral width, which even out the soundstage more. On the Immanis, again I ended up preferring ultralinear. I do think there are going to be other amps that stage even larger, especially with the right tubes, but I suppose this is one of the downsides, relatively speaking, of the amplifier.

Miscellaneous Bits & Quirks

The Soul 170HA comes with a remote control for volume. I always appreciate remotes when they are included and miss them when they aren’t. The Soul’s remote is solidly built out of metal, with three buttons, mute, volume up & down. No battery is included and the type of battery required is a single CR2032 disc type. The volume adjustments with the remote are just a tiny bit larger in increments than I’d prefer, but that’s a minor gripe that’s negated largely because of the convenience of simply having a remote. The IR sensor is also cleverly built into the center of the volume potentiometer, too.

I also have to point out the weight of the units. The combined weight of the amplifier and the separate power unit is about 80lbs. Stacked up together they also take up a decent amount of cubic real estate. Speaking of the separate power supply unit, there are actually two umbilical chords with Lemo-style connectors. One provides higher voltage while the other provides lower voltage, which I believe coincides with the 4.4mm output, I could be wrong. Pretty interesting design choice to separate them.

Both the amplifier and power supply unit generate heat. Both are pretty warm to the touch, but not hot. The component that seems to emit the most heat are the KT170 tubes. The driver and rectifier tubes also are hot, but seem slightly less so, compared to the power tubes. However, the overall unit runs a bit cooler than my previous amplifier, the WA23 Luna. Realistically, this will heat up your room just like almost every other tube amplifier.

Another relative gripe to note, on more sensitive headphones and IEMs, I can pick up wireless/cell digitized noises, as well. It’s not just the hum or hiss from the tubes, either. So that’s something to note as a bit of a quirk. I also had to add isolation feet to the amplifier as well. Since it sits directly on my table top, vibrations and bumps would transfer through to the chassis and tubes and heard headphones (when no music or it was playing quietly).

I also am mildly disappointed that there is no preamp capability with this amplifier. The WA23 Luna I had prior did and while it wasn’t something that was used often, having the option was certainly really nice, especially as I searched and possibly still search for a solid state. However, I’m a realistic and know how versatile this amplifier already is, I know there’s gotta be some limitations. It’s really hard to imagine how much more they could make it do. So I digress.



Wrapping Up

At the beginning of this review, I claimed they succeeded in making a product that is bold and creates a statement. If you happened across my review of the WA23 Luna, you know that I professed that amplifier a statement piece. To borrow the term once again, the Cayin Soul 170HA is yet another wonderful statement piece. It’s eye-catching, it’s bold, and it’s a conversation starter. With the Cayin Soul, however, it is a bit more recognizable and traditional as a piece of audio equipment, versus the WA23 Luna. It’s no less striking and no less unique, though. It doesn’t just look good, it doesn’t just sound good, it also feels good, too. Everything has a premium feel, from the remote, the switches, the connectors, the chassis, including the wooden panels, VU meter, volume potentiometer, and even the faraday-like cage that protect the tubes.

The sound itself is powerful, refined, engaging, and without fatigue. Subjectively, every headphone and IEM that I’ve put on the amplifier has sounded better than I’ve ever heard them before. This is not a neutral amplifier, leaning a bit more on warmer side, but it still highly resolving across the frequency range. There’s also texture aplenty. It’s not the be-all-end-all in sheer sound grandeur, but you do have a lot of flexibility to cater the sound more to your liking. I do hope that eventually we will be able ot roll KT170 tubes, but for now there’s still lots of choices with the 6SN7 and GZ34 tubes. The amplifier still gets massive kudo points for its flexibility and versatility.

The Cayin Soul 170HA has been wtih me now for over a month now and I am just as eager to listen as I was when I brought it back from Can Jam (a big shoutout to Andrew DiMarcangelo and the entire Bloom Audio team). Again, I was not looking for an amplifier to replace the WA23 Luna, but Cayin certainly had something to say in this regard. It will not be everyone’s first choice, some will prefer the WA23 over it, others will still gravitate towards the Feliks Envy. However, for this guy, personally, I’m sure I leave you with no doubt where I stand. Regardless, this statement piece deserves to be talked about and considered if you are looking for a top end tube amp. As I wrap this review, I sit here listening to it still. Today alone I’ve probably clocked about nine hours of listening on the amp (one of the benefits of working from home). I can tell you, I am eager to continue the same trend tomorrow and the next day, and so forth.

(Here’s a picture of me enjoying the Cayin Soul amplifier for the very first time in the Bloom Audio room)

Beauty and Brains! Everything you could ever want…and more!

Introduction:
Coming into the world of headphones, I believed amplification didn’t matter much. The more interest, aka money, I put into the hobby I started to learn that couldn’t be further from the truth. In my narrow minded way of thinking, I just assumed the headphone was only going to sound one way.

If you’re getting ready to sit down and read this review, then you already know that my old way of thinking was a bit naive. To give some insight, just work with me, this isn’t going to be like one of those recipe links where I tell you my life's story, I started with a Monolith by Monoprice. Thinking that was all I would ever need. I started to read reviews on Head-Fi where all these people were making such “bold” claims about amplification. Well, I’m here to tell you those bold claims were accurate. The Cayin soul is hands down the best Amp I have ever owned. Moving from my OG Monolith I purchased the Topping A70/D70 combo. I found out what power can truly do. Then jumped to the Ferrum stack. Which we all know and love. My next venture was to get into Tube amps. So why not start with the Cayin HA-300mk2. Which I still think is one of the most underrated tube amps out there, for the price. But then I heard the Soul. When it comes to tube amps, I’m not sure I’ll ever want to experience more than what this has to offer. Cheesy PUN incoming, the Soul truly gives everything you listen to a SOUL.

Gear Used:
Ferrum Wandla Goldensound paired with Ferrum Hypsos - Tidal (Multiple IEM’s/Headphones see signature)


Build Quality/Design:
One thing that can push my buttons a bit in this hobby is the amount of money some companies will ask for. The higher the price tag, the more I expect in terms of build, quality, the parts used, etc. I think that is a universal truth in almost everything. A few companies out there have gotten used to asking for more and more without providing that same quality that correlates to the price tag. I can say the Soul in every way feels like a premium product. You would be hard pressed to find a better built amp. The quality is everywhere. The tactile feel of the switches, the soft turn of the volume knob, the beautiful glow from the VU meter, the power supply link cable, and the robust/sturdy tube cage. You truly feel it in every sense of the word, quality.

The design of the amp is well…heavy. It weighs over 50lbs and you’ll want to supply a proper shelf to support it. I truly enjoy just sitting and staring at the unit. I feel they’ve captured a very industrial new age look with their design. It’s no WA-23, but it sure looks like it could beat his ass in a fight . The array of the tubes is perfect. The KT170 standing proud ready to defend the 6Sn7 and GZ34S. With the subtle black backdrop of the encased transformer. The subtle orange glow from the VU meter emitting from the top as you see the needle dance around. I really only have two “gripes” with the amp and that would be its pure heft and size. Of course the amp puts out some heat, but not nearly as bad as previous tube amps I’ve owned. The KT170 being the biggest culprit of the heat. But again, still not as bad as previous amps.


Input/Output Connections:

The soul has 2 inputs XLR and RCA. You can have two sources hooked up at once. Providing a firm CLICK when switching between the two. It doesn’t offer a huge array of inputs, but I’m not sure what else you would be looking for here.

I love that it has 6.35mm, 4.4MM Balanced, and 4-pin XLR balanced for outputs. Alongside those it also has stereo speaker outputs. Probably won’t power a couple towers, but can handle some bookshelf speakers no problem. I hooked them up to my KEF bookshelves and added some warmy goodness to them!


Accessories/Unboxing:

Not too much going on here. You receive the robust power supply link cable, a solid remote, (2) KT170 Tubes, (2) 6SN7 tubes, (2) JJ GZ34S Tubes, White Gloves (for handling the tubes), and a power cable. Typically you’ll need to provide your own RCA or XLR interconnects. The unit ships in two boxes. I like how they did this as it brings the weight down a good amount and truly limits the risk of them being damaged. My unit shipped directly from Cayin to the states with no damage to the boxes or anything inside.

Features:

I will go into more detail about most of these features below in sound. Just want to state everything the amp is truly capable of.

• Class A amplification. Which provides 18 watts per channel. So don’t hesitate in plugging your Susvara up to the Soul. It’ll handle it with ease. Some of the best low end they’ve ever had!
• Separate power supply that can be hidden from the rest of the unit. Which is great in terms of the amount of space this unit can take up.
• Steel and wood construction. The amp is built like a tank.
• 3 different headphone outputs.
  • 4-Pin XLR - 12-18WPC
  • 4.4mm - 2-4WPC
  • 6.35mm - 7-17WPC
• The 4.4mm output was adjusted to handle low impedance headphone/IEM’s. Making this amp able to power every headphone/IEM in your catalog.
• 2 sets of inputs - XLR and RCA
• Speaker outputs providing 18WPC. Good enough for most bookshelf speakers.
• Triode vs Ultralinear Operation Modes - See Sound for more detail.
• Dynamic vs Soft Tonality options - See Sound for more detail.
• Impedance matching for headphones with 3 separate load options.
  • Low - 8ohm to 64ohm
  • Mid - 65ohm to 250ohm
  • High - 251ohm to 600ohm
• Solid Remote Control
• Gorgeous VU meter design at the top of the unit.

Sound:

Now you’re going to have to stop me if I start to repeat myself. Out of all the equipment I have owned, borrowed, and listened to through the years, I have YET to find an amp that has satisfied ALL of my needs/wants in one package, let alone a tube amp. I was always partial to solid state amps. Their accuracy, sound, quickness, always beat out any tube amp I ever came across. Some of the features that the Soul has puts it in contention against most solid states. The best feature being it’s ability to switch between Triode and Ultralinear. You would never expect there to be that big of a difference between a simple flick of a switch. But there is. The amp truly wants you to hear the difference between almost a more dedicated “tube” sound vs that more solid statey sound. If there was ever an amp that you could purchase without wanting an SS, this is the one. While in Triode mode it’s a smooth sound. Accurate and sharp with it’s imaging. Focuses on pure Vocals, amazing with orchestra music, and provides such an accurate/detailed separation of instruments and provides some of the best Timbre from a tube amp. It’s beyond impressive. The mid-range seems to be the biggest focus while in Triode mode. Which there are nights, that’s exactly what I’m looking for depending on the music. But when I want to switch it up and have some fun, I make a quick turn to my right and flick a gorgeous gold switch to Ultralinear Mode. No one has ever said it better than Michael Buffer, “Let’s get ready to RUBMLEEEEE.” Because that’s what we are about to do, RUMBLE! Ultralinear is the most fun I’ve ever had on an amp, all with just a simple flick of the wrist. The fact that it’s even an option is what makes me love the amp. I feel, more often than not, other manufacturers will add different output sounds but they never seem to live up to this. In UL mode, it’s not just fun. It still holds onto that accuracy, that imaging, the vocals. But adds an even more open stage, a more dynamic feel, and brings out that low end that I know a lot of you love/want! It takes the round hole and makes it square. Between the two, I find myself in UL more than Triode, but Triode always has its time to shine with me. But those aren’t your only two options. They decided to throw in a Dynamic and Soft tonality switch! I know, I know, it’s almost too good to be true. The difference between these two is much more subtle. Still adds a slight adjustment, by changing the current of the KT170 tubes. Dynamic you’re going to get that fast accuracy with authoritative punch that you would expect out of a dynamic sound signature. It hits hard and lets you know it's what you’re looking for. Soft portrays that more relaxed feeling that gives you a bit more detail from your music. If you want to hear things like you would from a SS then Triode mixed with Soft tonality is your key. Outside of the minimal noise this amp creates for being a tube amp, it’s almost hard to tell you’re not listening to a SS amp! The greatest thing about owning the amp is every day I am so excited to come home and hook up another headphone and or IEM to it. Oh yeah, you can run IEM’s off of this tube amp with minimal background noise. Once the music starts, you’ll be hard pressed to actually hear it. I can’t name many Tube amps that allow you to do that without a good amount of background noise. Now to repeat myself again, I’m not sure you can find a more fun amp to listen to. I’ve enjoyed every moment with the Soul so far. It’s added more value to everything I’ve plugged into it! On top of that, there isn’t a headphone I haven’t been able to plug into it. From Susvara, Tungsten, Novus and Macbeth it handles all of them with ease. Having three impedance matching options is great (L/M/H). Able to power every headphone in my collection with one amp is everything someone like me would need. As you can tell from my signature below, I have some of the easiest IEM’s to drive to the hardest headphones. I can honestly say I’ve never heard the Susvara sound so alive. The ferrum stack did them justice, but the soul truly brings out the SOUL of them. Trust me, I’m not done using that one yet.
Bass - The bass is the star of the show when it comes to Soul. This can be adjusted down with the flick of the switch, but when you want more weight the Soul just does it so…Well. It hits hard, fast, accurate, low, and on and on. It doesn’t muddle it throughout the rest of the music and doesn’t take away from anything else on the stage. I’ve never heard an amp create such an accurate and gorgeous bass sound. You’re going to be coming back to the amp just for this alone.
Mids - This isn’t far behind from the Bass. I almost want to say it’s on par. The mids with the soul just have a way of being so pure. I’ve noticed with previous tube amps the mids can get a bit lost and be a bit behind. But the delivery on the Soul is nothing short of spectacular. The rich details, pure/clean sound, with a natural reproduction of vocals and textures. I found the Soul delivers a new perspective on Female vocals for me. In the best way possible. Took any kind of harshness and gave them a more accurate representation.
Treble/Highs - I would say the Mids/Bass truly take the show on the Soul, but by NO means does that mean the treble is lacking. It maintains an impressive level of detail. Timbre without adding color. Very tactile, snappy, and sparkly (depending) but has never come across harsh to my ears yet. I can be very sensitive to treble peaks. The Soul has helped roll those off a bit, making it much easier to listen to certain songs or even certain headphone/IEM’s.

Headphone/IEM:
Most testing was done in Ultralinear/Dynamic mode - unless stated otherwise.

I could truly sit here and write up every headphone/IEM in my collection, I am enjoying this AMP so much. It would allow me to sit here and just spend time with each one. But if I did that this review would be the longest in Head-Fi history. I’m that enamored with this amp. But I will limit to a few…plus some I know there are a few different ways you can listen to headphones on this amp, but will generalize for each as best I can.



Hifiman Susvara - truly this headphones best form. Almost like they were meant to be together. For a while I was thinking about upgrading to Unveiled, but would have a hard time parting ways now. I could almost say the amp gives the OG a more “unveiled” sound. I found even more enjoyment listening to female vocals. I use my Susvara a lot when listening to classical or piano. I’ll usually switch over to Triode/Soft as it pulls more detail from the music. You can hear the movements of their fingers across the fingerboard, the pull of the bow hair down the strings, and almost like they're sitting in the room with you.

Kennerton Heartland (Purpleheart) - This headphone impresses me more and more every day. Purchasing the Kennerton was a simple drank too much whiskey/bourbon, it was sitting in my cart, and I clicked buy now. I haven’t looked back since. They’re just a fun headphone that still provides all the details. Which you don’t seem to run into very often. The Soul puts in a bit more low end and broadens the soundstage on these. It’s truly a great pairing. It provides more detail, deeper articulate lows, and mids that just about everyone would enjoy! The heartland/Soul combo might be one of the favorites in terms of headphones yet..



EE Novus - Get ready to not want to plug these into another setup moving forward. I ended up ordering a longer custom cable so I could sit comfortably at my computer and have these in my ears at the same time. The Novus is the IEM that was meant to be with the Soul. It’s my favorite IEM/Amp combo so far. It’s added so much detail, more life, more weight, more mid-range, more well, EVERYTHING. Every genre of music shined with the Novus while paired with the Soul. What I enjoyed the most was it pulled out the tiniest treble peak the Novus had. It’s not even a peak that bothered me, but rolled it off just enough to make it perfect. The Novus was already my favorite IEM with the Enleum, but the Soul pretty much said “hold my beer.”



Forte Ears MacBeth - The MacBeth was my biggest surprise of 2024. I got to experience them at CanJam SoCal this year and without hesitation I walked over to MusicTek to get an order going. With a quick shout out to Andrew over at MusicTek for being super easy to work with and I will continue to work with for future purchases. The first thing I noticed about MacBeth was the tuning. I love the soundstage. The mids are truly some of the best I’ve heard. The Soul, once again, takes all of those things and amplifies them. The Mids are truly spectacular with the Soul powering them.




Comps:

Cayin HA-300mk2 - I honestly thought this was going to be the best Tube Amp I would ever own, again purchased from MusicTek. I was able to listen to just about everything on it. IEMS and some of my harder to drive headphones. It had some shortcomings in powering Susvara to its full potential. The tube rolling experience with the mk2 was one of the best parts. It’s honestly the only winning category the mk2 will get over the soul. Which if you own the mk2 it’s an amazing amp (severely underrated and should be owned by more people). Still a top tier for me. But upgrading to the Soul is 100% worth it.



Ferrum Oor - I know, I know, how can I compare to the solid state. Well, mainly because the Soul can almost act like a SS. It has such a low noise floor that it is possible to listen to all of your IEM’s. With how far IEM’s have come over the years, I don’t want to just use them on the road. Especially when I’m paying over $5k for a pair. They’ll be staying in my office next to the rest of my equipment. The Oor is one of the best SS out there for the price. Its power output is on par with the Soul. They both handle everything you throw their way. But the Oor is just that. Plug it in and turn it up. The features that come alongside the Soul truly set it apart from the Oor. In terms of sound I prefer the Soul over the Oor as well. I can say the Oor has been my daily driver for almost a year and I haven’t ever really considered moving away from it. But having the soul makes me even consider keeping a solid state amp around anymore…



Conclusion:

Ok, it’s obvious. I’m head over heels for the Soul. It’s added so much soul to everything I’ve put on there (see what I did there, again winks). The soul gets my recommendation all day and everyday. The musicality of this amp is by far the best I’ve experienced. While at CanJam, 4 units were sold. All of us sitting there talking about how it’s one of the best amps we’ve heard. This is a unit that will be staying in my collection for a while. It’s going to be very hard for me to part ways with it and then not crave its sound. Truly unique to itself, but also not changing anything. The soul is beautifully engineered, being very attractive to look at. One of its only shortcomings is its weight/size. The sound quality that Cayin creates with the Soul is the best I’ve heard to date. Now grab your drink, find your chair, and get comfortable. Because once the glow from those tubes light up, you’re not going to be moving for a while.