The Cayin SOUL 170I Integrated Amp Review.
By Steve Huff
Just three months ago I saw an all tube integrated amp online from the brand Cayin and it was drop dead gorgeous in looks but I wasn’t sure if it would be an amp that I would enjoy so much as it used and housed KT170 tubes, one of the most powerful vacuum tubes in the world. I have heard from some friends over the years (who are also into audio) that this tube is said to sound bright or hard (by some). Hmmm. Even so, I put this Cayin amp in the back of my mind and thought about it a lot as the design really hit me in all the good kind of ways. I loved the style and looks 100%. In fact, if I designed a tube amp, I would want it to be as cool looking as this one as it just may be my fave design ever for an integrated amp of the tube variety.
The name of this integrated amplifier is the Cayin SOUL 170i. This is an all tube all analog integrated amp with several inputs, even a balanced input, one of them, is here. The SOUL 170i can also be used with a preamp as a standalone amp and uses all premium parts inside as well. Cayin tube amps are always very highly regarded but I have never been able to review one or have one in my own room, until now. I have seen them in the flesh though, and they always look world class with the high quality build and attention to detail.
The Cayin Soul 170i up close
After thinking about this amp for a while and wondering how I may get one to check out, one day out of the blue I received an email from Larry at HighEndPalace.com asking me if I would like to review the….yep you guessed it, the Cayin SOUL 170i that I have had running in my brain for a few weeks! I said yes of course to Larry and about a week later the amp showed up at my door in al of its 98lbs glory.
When I unboxed the SOUIL I was not prepared for the insanely high quality of build, parts and solidity. I really wasn’t. This amp looks like a $15k integrated as it does have some truly gorgeous looks. I was so curious as to how this was going to sound with my various speakers and I wondered if the KT170 tube was going to sound bright or etched. I couldn’t wait to test this one out and I did just that.
A gorgeous integrated amplifier in every way. Does the SOUL 170i have a soul?
The Cayin SOUL 170i has been in the system for a bit now and it is, without question… the finest tube integrated ampI have ever heard, used or tested. In fact, this is the first tube amp in well over a decade that bests my previous long time personal fave, the Line Magnetic 219ia (for me). They are quite different as the 219ia is Class A amp and the Cayin is Class A/B, but the SOUL has more going for it vs the 219ia IMO. Both are stunners of a tube amp, but the Cayin is more refined, even nicer in materials and workmanship and sounds like more like a 219ia on steroids. It can drive many more speakers as well as it has much more power. With that said. the power doesn’t tale away the SOUL 170i’s tube delicacy when called upon.
This line magnetic 219ia has been my all time fave tube integrated amp for over a decade now. It’s still in production, and IMO is now a classic. The SOUL 170i from Cayin is a different beast for sure, and is the first amp that I like better in the tube world vs this 219ia. The CAYIN runs cooler, has more power and can be just as delicate. The 219ia is a shade warmer and has that SET amp immediacy and vibe.
Line Magnetic is still today one of the best made Chinese brands when it comes to tube amps. The LM brand of tube amps rival any tube amp, made anywhere, regardless of country or origin. Cayin sits right with them and offer up similar quality, if not even better. These are premium amps and nothing here is second rate. Rather, you are getting a ton more for your money with Cayin and LM.
I have owned and tested maybe 30-40 tube amps in my 40 years in this hobby, not a ton of them but enough to know the type I enjoy the most. I have always enjoyed tube amps that use 845 tubes, 300b tubes, 6SN7 tubes and EL34 tubes the most. I have only truly fallen for 3-4 tube amps in my lifetime. The Line Magnetic 219ia above is one of them and in this image it sits in my old audio room when we lived in Arizona. A Cary 850C was another set of mono tube amps I loved as they were also a SET class A set of amps. A third was a model from airtight that I can not remember the name of at this moment. I even loved the Line Magnetic 300B amp that I heard and saw at a dealer one time. I like a tube amp that’s sounds like a tube amp and for me this means a big solidified sound that is not lean or bright along with a nice 3D holographic soundstage and some warmth. The Cayin fits this profile as it’s detailed (though not overly detailed) and a bit sparkly but full of body and some warmth and also has a huge sense of POWER.
Cayin is made in China, yes indeed but like Line Magnetic they are all out superb in their designs, quality and workmanship. This is not a fly by night company selling amps on Amazon, but rather an established brand that has been praised for years by so many for the all out quality and design. Anytime I see a Cayin amp online it aways looks beautiful. The SOUL 170i is a work of art for these old eyes and even a conversation starter, at least it has been for me here in my space. In person it looks and feels much nicer than even the impressive images of it show.
This SOUL 170i also has one of the coolest looking tube cages I have ever seen and it too is a work of art. So many tube amp makers skimp out in the cage area but here. I never… or should I say I “rarely” use cages but for this one I like it on and as gorgeous as it looks off, when on it will protect anyone (kids, pets, yourself) from burning themselves on the KT170 tubes, that get scalding hot.
THE DESIGN and the SPECS
First of all, this is a full fledged all analog tube amp. There is nothing digital here and it is also hand wired, point to point and it’s done in a very nice well done way.
This amp has two modes which are accessible from the front of the amp or the all metal “solid as a weapon” remote control. First there is Triode mode which puts out a whopping 75 WPC and produces a sound that has warmth and a heart hugging vibe. This mode is so sweet with vocals and acoustic instruments and feels relaxed, big, open and sweet.
Then there is Ultralinear mode which puts out 135 WPC and sounds more powerful, dynamic and more detailed, yet retains a big portion of the warmth, body and density and adds more dynamics, punch and bass kick. It’s stunning to hear a tube amp deliver this kind of power and drive, and its stays refined, smooth and composed no matter how loud I turn it up.
Make no mistake, the SOUL SOUNDS LIKE A TUBE AMP, not a modern day solid state sounding amp, though it sounds more electric, detailed and open vs something like a Cary 300 SEI or a 300B tube amp.
There are three singe ended RCA inputs and one balanced input on the 170i. There is an input to use the 170i as a power amp as well if you want to use your own preamp. There are also a pair of subwoofer outputs via RCA if you want to add a sun or two. Nice.
There are four Kt170 tubes, one 6SN7, two ECC83S tubes and one oddball tube I never heard of called a 22DE4 and the one inside of the SOUL is a NOS version of this tube. Retubing this bad boy will set one back about a grand when that time comes years down the road due to the cost of the KT170’s. They cost around $150 each, so that’s $600 already and this is one of the “cons” of a tube amp, the cost to replace the tubes when they die out, hopefully many years down the road.
On the front of the amp there is a huge and slick analog volume knob that lights up with a notch on the big dial so you see where the volume is set at. I just love big volume dials and this may be the nicest feeling one I have felt in ages. It’s smooth, weighted and just feels quality without any grit or roughness. The light dash on the volume dial is perfect as many amp makers skimp on this. It’s nice to see where you are at during those nighttime listening sessions.
There is a power button on the front left that also illuminates and on the right side you will see the input selector sand triode/UL button. The remote has this as well and you can switch in an instant, no waiting, right from the remote. This helps dial it in for each song and it takes half a second to do.
What about hum or noise? Well the good news is that there is no noise from this amp at all because it was made right and uses all HQ parts inside. This is a high end tube amp right here. The build is pure quality. I see a ton of amps every year and this is one of the finest in build I have seen in a long while. I have had high end amps in here too like the Nagra HD Pre and Classic AMP ($100k) as well as Daniel Hertz ($20k) and McIntosh ($15k). This looks as high end as any of them.
The amp has quality feet and speaker connectors as well. Nothing here is cheapened out and you can tell as soon as you look at it. The paint job is super high gloss on the chassis, in black. No, not just matte metal with screws showing here. The transformers on the back are massive and again, buzz and hum free. This amp weight in at 88bs. Also, when people see this amp in your space they WILL ask you about it so be prepared.
SPEAKERS
This amp can power almost any speaker due to the fact that it has so much pure tube analog power. I have run 85DB efficient speakers in my room with an 8 watt tube SET amp. This one offers 135 watts and has zero trouble powering the same speakers to insane levels. The SOUL is not a wimpy tube amp with flea watts of power. This was designed to power almost any speaker so you can power your speakers as low or high as you want to go but be prepped as the bass quality of this amp is crazy big. If you want solidity and a big bass foundation without slop, this is an amp you may want to look into.
I tested the Soul 170I with my reference Icon 12 (94db efficient) speakers from Norway, my Buchardt E50 (87db) and my Pure Audio Project Duet 15 Horn (98db). All speakers I really enjoy listening to and they all bring their own flavor of sound to my space but yet the SOUL 170i powered them all with an effortless and very refined sound.
You can FEEL this amp if you have speakers that are up to the task and in fact this amp powered my three speakers here to the best I have heard them in tonality, timbre and just how big they sound. This SOUL 170i has become my “Dream Tube Amp” as it sounds so amazing with the speakers I own.
The Class of SOUND
This year I have had amps in here that are Class A, Class A/B and Class D. I have had solid state, tubes in the form of SET amps and even push pull tube amps. I have never heard two amps that sound exactly alike but in each class, there are similarities to the vibe of the sound.
With the Class D powerful French made Devialet Astra, the sound is fast, transparent, detailed and clean with tight and insanely controlled thunderous low bass. Perfection for those who like distortion free powerful sound with no detail left behind. There is a hint of warmth in the midrange of the Astra as well, without it the amp would sound too clean. It’s as good as I have heard Class D bit it’s more about the rush, excitement, power and hearing all a recoding has to offer.
The powerful $20k+ Astra which houses a class D amp, dac and streamer.
With the Class A sound you get immense detail yet also big body in the mids and some warmth as well but Class A solid state still sounds clean, sparkly up top, rich and highly layered. It’s quite the sound and I have always loved Class A designs. Class A tube designs often sound warmer still and Class A SET tube designs, like the Cary 300SEI, are even warmer sand beefier still with the mids projecting a HUGE voice into the room. Class A will also bring your energy bills up quite high as they cost the most to run, even when idle.
Class A/B seems to offer a great balance between Class A and modern Class D as it has more drive, energy and speed than Class A but also has more warmth in the body of the music and usually the nicest bass performance vs Class D. Class A/B is the most common type of amp on the HiFi Market. Sometimes Class A and SET amps are considered almost Niche.
The SOUND of the SOUL
The Cayin SOUL 170i has a unique sound due to the tube compliment and immense power behind it (for tubes). Being Class A/B and push pull, like most tube amps on the market, this one offers up a great balance of sound quality and power savings vs Class A. This amp has a massive sense of power and refinement in sound but it is smooth and yet also dynamic and exposes details gently vs hard or etched. Your front end will also have an impact on this such as your streamer, DAC or Analog vinyl rig. Overall though the sound of the SOUL is warm, beautiful and rich in triode mode and more exciting, dynamic and powerful in UL mode.
With the Eversolo T8 Streaming Transport and the FEZZ Equinox DAC I could not ask for better sound with any of the speakers I tested the SOUL with.
As I sat and listened during my extended time with the SOUL 170i I kept telling myself that it sounds more like a Class A amp than A/B. It has a huge sense of power, immediacy and bass. The midrange is cleaner and not as full bodied as my Cary 300 SEI but there is more lower level details that emerge with the SOUL 170i, and yet it keeps the solidity and richness of the Cary.
This is also an amp that sounds beautiful with any music you throw at it. It doesn’t have a hard, grey or harsh bone in its casing yet it’s not what I would call bloated, not at all. Whether I was listening to old 80’s awful quality recordings or audiophile classical recordings, my Icon 12 or Duet 15 Horn speakers were a perfect mate and just wowed me night after night.
The SOUL 170i and the Pure Audio Project DUET 15’s with the Horns. This is the best I have heard them yet and it’s no contest. I love these speakers as much as my main Ic0n 12. I guess that is why I still own them!
Swapping Speakers
When I switch to my Buchardt E50’s I hear them wake up like never before, with the bass also being more prevalent and rich than I have heard them prior. They sound big, juicy and effortless here when I switch to the Ultralinear mode on the SOUL with the E50’s…wow, what a sound it is. It keeps warmth but drums are bigger, bolder and more powerful. Guitars jet out with power chords that sound 3D and the sound stays smooth and like silk.
I used to own Cary tube amps (V12R for example) back in the late 90’s that had the UL/TRIODE switch and when I would switch to Ultralinear, the sound always hardened. I never liked it. Here, with the Cayin, UL mode sounds AMAZING!! It keeps warmth and body but just brings voices and instruments out a but fiurther into the room. I usually almost always prefer Triode mode in tubes amps but not here. Most of my listening was done in Ultra linear as it is implemented so well.
The lovely Buchardt E50’s produce a HUGE sound from a SMALL box. Bass? Yea, these go DEEP and the SOUL 170i does them full justice.
The KT170 Tubes in the SOUL 170i
The KT 170 tubes are quite an achievement and are in no way bright or etched as some have told me, at least in the SOUL. It’s really all about implementation I guess, and the way Cayin built this amp, the KT170’s sound like a majestic tube meant for Royalty in the SOUL.
Anytime I have a tube amp I always have a spare set of tubes, just in case a tube blows premature, which can happen. I already own some of the nicest 6SN7’s I have heard in the PSVANE Summit series tubes and this is what I would use in this amp for the 6SN7 tubes. It ships with some standard 6SN7’s so that is the first tube I would upgrade if I had the itch to do so, and I did in this one. The PSVANE Sunnit tubes are some of the nicest sounding new production tubes I have heard. These tubes along with those from RayTubes.com made me stop looking for NOS tubes, which are now insanely priced and IMO, no longer worth the search for me. The 6SN7 SUMMIT tubes can be found on Amazon HERE, via Prime. Unless they are sold out, then you will not see them at that link.
TRIODE MODE IS SO SWEET
As I sit now listening to Andrew Bird’s “My Ideal” in Triode mode on the Icon 12 and his voice is so big, present and clean yet there is a correct kind of fullness to it, with what appears to be the reverb trails from the studio that I never noticed like this on my other amps. This track sounds best in Triode for sure as it’s all about the vocals and the acoustic bass and instruments. He pops out in the room with a large as life presence. Lovely, as good as I have heard this and sounds better, more layered and refined, than the Cary 300SEI with upgraded tubes.
The sound of the Cayin is very refined and by that I mean there is no hardness, grunge, edge or brightness, even if blasted to high volumes. The sound is silky smooth and devoid of even 0.1% of grnnge or grit. It stays clean but never antiseptic. It sounds powerful and with big bass but doesn’t get bloated or sloppy, but this may also depend on your speakers. If you have speakers that are sloppy with the bass, no amp will tighten them up. With my Icon 12, Duet 15 horn and Buchardt E50 the bass is simply incredible.
WITH PURE AUDIO PROJECT DUET 15
I have not listened to the Duet 15’s in quite a few weeks so when I carried them from my spare room to the listening space to hook them up to the Cayin I had no idea what to expect. With some solid state amps these speakers can sound lean or bright up top from the Horns. With the SOUL 170i and Cary 300SEI, I was having some fun with the Duet 15 horns. They sounded incredible and proved to me once and for all that these speakers really want tubes to feed them. My least fave amp with the Duet 15’s was a high power and faster sounding Class D amp. With the SOUL that sound bigger, juicier and richer than ever before. No brightness here, at all.
The Cayin SOUL 170i sounded heavenly with the Duet 15 Horns, and I mean so so good. My prior fave with these speakers was probably the Luxman 509Z but now the Cayin has taken that spot as these seem like they were made for the SOUL amp. This amp keeps the sound smooth and eliminates any brightness from the horn and wakes up the bass in a super cool way. It’s immersive and HUGE sounding, effortless.
I do also need to say that if you seek crispy super high res details from the treble area then this amplifier doesn’t do that. The treble here is smooth, with warmth and beauty in the mids and lower bass. If you want a tube amp that delivers “the feels” and sweet details without overdoing it, the Cayin sits among the finest of its kind I have ever experience. That’s what this amp was for me, an experience. It sounds like music vs hyper fi and when I listen, I find it hard to pull away. Always a great sign of a good amplifier.
A CONFESSION
A few years ago after having tubes fail in an amp that cost me $900 to re-tube I decided to go to solid state for a while and explore those options. I went without a real tube amp for years and after a while I started to feel as if Solid State was the best option for me. No tubes to ever go out, less noise, heat, etc. With that said, it can be hard to find a stunning sounding solid state amp but they exist and usually, my faves, always seem to cost a fortune with a few exceptions.
So I was enjoying solid state snd my ears got used to the sound which is usually leaner, more detailed and more electric and lit up vs tubes that have warmth and beauty. I even stated last year that I would not go back to tubes due to the maintenance costs and the heat many of them produce, but in reality I do prefer the sound of tubes, especially with an amp like the Cayin and others I have heard recently.
After living with some of these tube amps over the last few months…the Cary, the Oilily, a FEZZ Titania, a Galion TS120, the Brunoco Terra and now the SOUL 170i I find it hard to go and put my solid state amps back in! Now they sound leaner and more strident than before. My ears have now once again gotten used to the tube vibe with the warmth and layering tricks that they seem to do.
As of today, here in September 2025, my ears are clearly enjoying tubes more than solid state with the speakers I have here now so I may switch back to tubes for the next couple of years, just as I did with solid state for the last few. With the speakers I own now it is obvious to me that tubes are the way to go for my own listening enjoyment and even to recommend to you, if you own the Duet 15 or Icon 12.
I would not have committed to going back to tubes if I never experienced the SOUL 170i. It’s just so damn good in every way.
BUILD QUALITY? Yes.
DESIGN? Yes!
Features? Yes!
Quality Remote? Yes!
SOUND? Gorgeous, so YES!
I will state now that I have never heard a better tube amp (for my tastes) with my Icon 12, Buchardt E50 or my Duet 15 speakers. This has a nicer sound than the old LM 219ia I love so much. It’s even bigger, cleaner and the way this amp does details is spectacular as they are not etched or sizzling but rather holistic yet a bit more exposed than the Line Magnetic . This amp is also h0lographic but I have heard other (solid state amps) that were moreso, like the Astra. The SOUL 170i has 3D depth and an organic imaging vs etched and drawn out in detail. Warmer, smoother and a more fulfilling emotional vs exciting listen.
This amp just makes the music so enjoyable, fatigue free and I will warn you now that it is addictive. It pulls me in with the richness, quietness and the full POWER of the sound. I can turn our room into a nightclub one night or believe we are attending a live concert the next. I can listen to some old school Jazz vocals and hear the recording just how they should sound or I can settle in for a night of ambient music that immerses me in deeply. Whether I want to sink into my seat with an adult beverage or get up and dance, the SOUL could do whatever it was that I wanted it to do. I could have sworn I heard Diana Krall whisper in my ear one night as I was listening to her last album but I was a couple of drinks in, lol. This amp is also fun.
The Cayin built in Bias Meter
BIAS
This amp does need to be biased but it is so simple to do. No meter needed. Just flip a switch and the built in meter will show you if your tubes need to be biased. If so, turn a screw until the meter needle is in the middle of the display. Super easy. This one was biased perfectly from the factory as this shipped direct from Cayin in China thanks to Larry at HighEndPalace.com.
When Larry from High End Palace contacted me we spoke on the phone and he really wanted me to hear this amp but he wanted me to check out the big gun, the flagship called “The Pearl”. He said the PEARL is the best tube amp he has ever heard but it sits in the $20k price range where the SOUL 170i is at $6999. He was going to send me that one, but I opted for the SOUL 170i due to weight and cost if I decided this was the one tube amp I have been seeking for my Icon 12’s.
The PEARL has to be stunning but the SOUL 170i is also a stunner, and attainable for more people.
ASSOCIATED EQUIPMENT
During my time with the SOUL 170i I used it with an Eversolo T8 streaming transport and a FEZZ Equinox tube DAC. That FEZZ is truly a special DAC and my current fave, at least for now. I also ran a Lumin U2 for a week or so and that brought a slightly more beefed up presentation vs the Eversolo T8 but I didn’t need that in this system, so the Eversolo sounded better here all around which surprised me. The Lumin U2 is one of the finest streamers you can buy for all out quality and function within the $6k price range. The Eversolo T8 is under $1400 and the fact that it competed and won in this system is remarkable.
As I dream of what system I would build around this amp, my dream setup would be the Soul 170i and a Lumin X1 that is the flagship Streamer and DAC of the brand. It’s still one of the best today and the sound is unreal of the X1. Yea, that would be gorgeous. As is though, with the Eversolo T8 and FEZZ Equinox it’s just so beautiful as is and costs way less than an X1 ($4400 vs $16,000).
The Eversolo T8 is one heck of a performer when it comes to streaming. I have zero complaints.
CONCLUSION
I know some people just drop here to the conclusion for the last word but I think you should read the words above if this is an amp you are considering. I will keep this part short instead of repeating the praise I poured over the SOUL 170i above. This is, without question, the finest tube integrated amp I have ever had the pleasure of testing and writing about, so far in my 40 years into this hobby. I like it more than my decades long fave, the Line Magnetic 219ia. That says a lot right there as this is the first tube amp that I can say that about. I also prefer to the Audio research VSI 75 I adored so many years ago, There is an ultimate refinement here to the sound that I have not heard from any other tube amp, to date.
The SOUL 170i is just all out a beautiful thing to behold when it comes to looks as well. A work of art that is functional and sounds divine. It’s two modes, triode snd UL, are super useful here and you can easily hear the change from warmer, more inviting and emotional to the more power drive of UL. Soft music sounds best with Triode mode and heavy music, UL. I love that it is switchable instantly from even the all metal remote. No clicks, pops or noises either as this is a quiet beast as in I hear no noise coming from it or my sensitive speakers as I just hate when that happens.
The soundstage in Triode is more laid back but does bring out those smaller details from the depths of the recordings in an organic way. When Ultralinear is activated the stage gets wider and details pop out more into your space vs triode. Both are smooth but UL sounds more powerful with bigger more dynamic drum kicks and tighter and even bigger bass. It’s like two amps in one as both sound quite different here.
Speaking of the remote, it’s also one of the finest remotes I have seen with any gear. The remote bests Luxman, Cary, Mcintosh or any other high dollar amp I have had in here. It is second only to the amazing remote of the Devialet Astra, which is the coolest remote ever made. The Astra is a $20k+ amp. The Cayin is $6999. The remote here is nothing fancy as it is a full metal black remote but the finish and quality is superb. The buttons are nice and the text looks good. There are even smaller rubber feet on the bottom, which is nice when setting down on a surface. Cayin seems to think of even the small things.
This amp brings the tube sound 100% and is not trying to be an amp with a “modern” more lit up sound with a leaner midrange and tighter bass, thank goodness. This is the real deal and as much as I love the Class A SET sound of the Cary 300 SEI and Line Magnetic 219ia, this one bests those in a few ways but does lose out to the Cary and 219ia in that SET amp immediacy that is so special. I prefer the Cayin here by a mile though as it just offers more in sound and function and looks like a million bucks. It’s more versatile as it can power almost any speaker due to the mass power on tap. This is a tube amp that brings power yet still sounds like a pure tube amp should. It’s like a tube amp made for those who want the best tube amp and sound they can get without going exotic.
Modern conveniences, all hand wired…I have nothing bad to say about the Cayin 170i SOUL. If it sounds like it is up your alley sound wise and design wise….
YOU CAN BUY ONE FROM LARRY OVER AT HIGHENDPALACE.COM!
Tell him I sent ya and he will treat you RIGHT!
