Headphoneus Supremus
Pros: Stunning clarity, beautiful tone, bottomless bass extension, gobs of power, excellent build quality, general aesthetics are very attractive, value is arguably high in the realm of top-level tube amps
Cons: Volume comes on strong quickly and steps are too coarse for fine adjustment with some headphones, background hiss on some headphones, no preamp capabilities, heavy/bulky, speaker outputs are very low power so not as useful as I'd like

Cayin has been around for quite some time, but within the last few years have really made a push into the personal audio space. Their iDAC-6 D/A converter, iDAP-6 file-player, and iHA-6 headphone amplifier make a brilliant stack. Their HA-1A mk2 delivers sumptuous tube goodness. And their numerous portable audio players have something to offer at almost every budget.

Having offered some extremely high-value designs for the headphone crowd, Cayin recently moved upmarket to try their hand at an extremely high end desktop amp. This resulted in the massive HA-300 headphone amplifier - a two-box, direct-heated triode design selling for $3,999 and weighing in at a combined 64 pounds. I spent considerable time with the HA-300 in my system but have been struggling to find time for a proper write-up... so here we go.


First off, I recommend perusing the HA-300 product page over at the site of North American distributor Musicteck. There you will see many details about the design and execution of the HA-300. Cayin has always been refreshingly transparent about the inner workings of their products, and this one is no different. Highlights: direct-heated triode design, point to point wiring with quality silver-plated wire, high-precision 24-step custom potentiometer encased with aluminum shielding to avoid interference, and - possibly most important - the custom designed, in-house wound transformers (toroidal for the power supply, EI core for the output stage). There are very few firms out there doing their own transformers these days, and it's such a crucial aspect of the resulting sound that it's nice to know Cayin has full control of the entire process.


Although I consider HA-300 to be primarily a headphone amplifier, keep in mind it also has speaker outputs at 8 watts of Class A power per channel - perhaps not enough for inefficient full-size, multi-way speakers in larger listening environments, but probably adequate for desktop or bedroom use with most stand-mount/desktop models. Or, with the right speakers (think Zu, Tekton, certain Klipsch, etc), even larger listening rooms could work quite well depending on your listening preferences. Still, I'd say the main draw here is firmly on the headphone side.


The HA-300 is, by its nature, a single-ended amplifier. However it does provide XLR inputs and 4-pin XLR outputs for maximum compatibility. All else being equal (which isn't always the case) I found that I didn't notice a significant difference in sound regardless of using RCA or XLR inputs. Same goes for the 1/4" versus 4-pin XLR output options. That said, some of my DACs are clearly superior via one output type or the other, so it's nice to have both inputs at hand.



The HA-300 can deliver up to 5 full watts per channel to headphones. It has adjustable output impedance which I tend to prefer on the lowest setting, but again more options are always welcome. The outboard power supply unit connects to the main amplifier via massively thick umbilical cable. We're talking nearly "garden hose" status, though it remains fairly flexible and easy to work with. The tube array is a combination of 6SN7 (and variants) for input stage, 300B for driver tubes, and 22DE4 rectifier tubes in the power supply. With just a pair each of RCA and XLR inputs, and no line-level outputs to speak of, the HA-300 is a purist design which does not double as a pre-amp. Along those same lines, there is no remote control, so speaker listeners will need to walk across the room to adjust.


For stock tubes, Cayin starts us off right - NOS RCA 22DE4, Shuguang WE6SN7 gold base, and TJ Full Music 300B/n dome top. Or at least this was the combo I was given on my review unit. It actually initially shipped with a different variant of the Full Music 300B but those arrived damaged, and I was told Cayin was switching from that point forward, so hopefully my review experience represents the current state of affairs. Users will certainly try their hand at tube rolling but I stuck with the stock configuration as it is A) excellent overall, and B) more relevant to the experience of a new HA-300 user.



I did some brief searching and found that the included Shuguang tubes appear to sell for around $160/pair, whilst the TJ Fullmusic set goes for over $300 (there are some significantly more expensive variations, and some cheaper ones, but I believe this is correct for the bundled tubes). Compare that with many amps (even very expensive ones) where the stock tubes go for $10-15. Not saying price always determines quality, but it's an interesting fact worth mentioning. Lastly, the rectifier tubes sell for around $24 for a quad, and I was unable to find any expensive examples of the 22DE4 which might be a significant upgrade. So despite this being the most affordable tube in the stock configuration, it may already be hitting maximum potential. Cayin had their choice of pretty much any 22DE4 tubes, and NOS RCA is what they went with. So I think that says something.

Since the HA-300 lived in my setup for quite some time, I got to try it with a large array of gear. The base setup, which remained constant throughout, consisted of the following:

*Equi=Core 1800 balanced power conditioner with Audio Art power1 ePlus AC cables for all components
*Native Vita music server with 2TB solid state storage, playing local files as well as Qobuz/Tidal via Roon
*Asustor AS6404T NAS with 24TB storage plus 512GB SSD running Roon Server (which is then controlled by the Vita)
*Titans Audio Lab Helen reclocker/jitter reducer
*Bettercables Silver Serpent Anniversary Edition RCA cables
*Bettercables Blue Truth II XLR cables
*Audio Art D-1 SE BNC cables
*B.M.C. PureUSB1 active USB system


I rotated several excellent DACs through the system while evaluating the HA-300. These included the B.M.C. UltraDAC, Exogal Comet Plus with WyWires umbillical upgrade, ModWright 205, iFi Pro iDSD, Wyred4Sound 10th Anniversary Limited Edition DAC, Audio Research DAC 2, and my reference, the Resonessence Labs Mirus Signature Pro.



For headphones, the selection included AKG K812 (recabled and modded to fully balanced) and K7XX, Sennheiser 650, HD660S, and HD800 (with Effect Audio cable upgrades), HiFiMAN HE1000v1 and Susvara (Effect cables), Focal Utopia, Elear, and Elex (Moon Audio Silver Dragon cable), Audeze LCD2/3/4 (Audio Art HPX-1SE cable), and Fostex TH-X00.

As a general overview, I find the HA-300 extremely quiet if not silent like my Pass Labs HPA-1. When I crank the Cayin's volume knob to full blast I can hear the slightest indication of vague background noise. This will vary depending on tube choice and I'm sure my balanced power conditioner helps lower noise floor, but overall I'd call this top notch performance from a tube amp. In my experience, SS amps seem to have more potential for complete silence, but Cayin comes pretty close to that ideal with the HA-300.

On the flip side, I find the gain to be generally higher than I'd prefer. I admit to being a rather quiet listener compared to many folks - I've got very sensitive ears and thus play at lower volumes than most. That said, the volume on the HA-300 comes on pretty strong even from the first "click" of the 24-step attenuator, and goes up in rather large increments from there. This is not a problem at all with most planars or higher impedance cans, but it can be tough to dial in sensitive headphones for those of us seeking modest listening levels. Again, I recognize that I'm probably the outlier here, and most people will be cranking the volume much higher than me anyway... but sensitive listeners with efficient headphones need to be aware of the situation. Note that this can be mitigated using a DAC with quality volume control, which I found did not impact performance since I was only trimming a small amount. Some sources don't have any volume control so that's not a universal fix.

Obviously, with this many headphones in the mix, it's a lot to get through. So I'm going to just break it down one headphone brand at a time.


The classic HD650 sounds unbelievable when driven by HA-300. By that I mean it really is hard to fathom that this thing has been around for decades, and is often derided as a "mid-fi" headphone. With the HA-300 and a suitably high-quality source, the HD650 has rich, lifelike textures, superb treble finesse, and punchy bass. I'm not sure I've ever heard it sound better. Other headphones may surpass it in one area or another but it's hard not to love the total package the HD650 delivers - when driven by a world-class amplifier. Volume here is no problem at all, with plenty of usable range and a dead silent background.

The newer HD660S is a small but pretty clear step down compared to its predecessor. It just doesn't scale as well, and the highs have some etch which isn't present on the HD650. The more sensitive design means volume comes in a bit quicker than I'd like, and there is just a touch of background noise (sort of a hissing sound) if you listen very carefully for it. Switching to a smartphone turns the tables in favor of HD660S, which keeps most of the same quality while HD650 becomes limp and lifeless. But when using a superb amp like the HA-300, you'll want to go with HD650 every time.

The HD800 pairs exceedingly well with the Cayin. Direct heated triode designs are known for their purity and tonal "rightness" and the HA-300 certainly embodies those characteristics - a good thing with the HD800 for sure. The presentation ends up being vibrant and supremely detailed while (mostly) avoiding that overly clinical HD800 feeling we have all experienced. Imaging and soundstage are world-class - perhaps the best I've ever heard. Low end response is punchy and tight, though still lacking the authority of something like the Susvara or Empyrean... just no way around that with this particular headphone. That said, it's still a thoroughly engaging presentation, and I may actually prefer HD800 here than when driven by my more expensive Niimbus US4+. That's extremely high praise indeed.

Like HD650, there are no issues with volume, and HD800 has a completely inky background.


The Susvara plus HA-300 is makes for a $10K combination. Let that sink in for a moment. Back in the day, many of us got into the headphone scene precisely to avoid speaker/amplifier combinations with five-figure price tags... so this is a weird situation to be in. Having established that, I can't deny that this is a very charming combination. Whilst my Niimbus drives the stubborn Susvara with more dynamic gusto, the HA-300 veers more towards sweetness of tone, with a beguiling midrange that defies any sort of technical evaluation. It's a tad forward, lush, and wonderfully euphonic, with a particular synergy on female vocals. Treble shows a purity, much like HD800 but more flowing and organic, whilst bass is wonderfully articulate if not as authoritative as it is with my Niimbus. Yes, the price tag is absurd, but the overall sound is very rewarding if you like a slightly more romantic presentation.

Switching to the first iteration of HiFiMAN's HE1000 which I prefer over the V2 (at least with the particular example I have), we get similarly expressive sonics with a slight shift in focus. This time it goes more "by the book", with a more neutral response overall. The one exception is the top end which has a gentle downward slope without going overboard. The presentation remains airy and extended (my listening notes say "ethereal") but at the same time can forgive a bit of harshness on poor recordings. Low end slam actually feels more prominent here than with Susvara, possibly due to the HE1000 being easier to drive. Susvara, with this particular amplifier, is all about that midrange magic while HE1000 spreads the focus around more evenly, and has a bit more midbass to create the illusion of impact. Susvara does extend lower but it's not as obvious with the HA-300 compared to Niimbus or Violectric V281. Overall an excellent combination which, in its own way, matches or arguably surpasses the Susvara but for less money.


This was probably the biggest area where my volume complaints manifested themselves. I listened with Utopia, Elear, and Elex, and all three had roughly similar issues. The lowest volume setting was already moderately loud, and the background was not as black as I'm used to with my other reference amplifiers. The former could be mitigated by using a DAC with quality attenuation - turning it down a bit on that end made certain loud recordings more palatable. The background "grunge" was never truly solved but I learned to live with it after a while. Despite my complaints, Utopia and particularly Elex made some beautiful music with the Cayin amp. Wonderfully fleshed out soundstage (particularly with Utopia) and superb instrument placement (especially with Elex) made these enjoyable despite their flaws. Treble was, once again, delicately balanced between detail and control, much like I had already heard with HD800 and Susvara. My listening notes include the terms "pristine", "fluid", and "vivid", and I meant those in the best possible way.

Elear was less successful - it already has my least favorite tuning in the Focal stable, and the HA-300 put too much focus on the already over-emphasized low end. The resulting sound was just too warm and somewhat murky for my tastes. I'm sure someone out there would love this presentation but for me it was just over the top.


One of the biggest surprises was how great the venerable AKG K7XX sounded via the vastly more expensive HA-300. I admit to not listening to these very often lately, but as I broke them out for this review I was shocked at how much they scaled. I'm used to the HD650 showing huge improvements with quality gear but I didn't realize the K7XX could scale similarly high. While perhaps not quite reaching lofty heights like the latest flagship headphones (which cost far more), this veteran AKG impresses with huge dynamics, nuanced treble, precise imaging, and rich, full bodied lower mids which in my experience is something 300B tubes do like no other. The K7XX impresses with an inky black background and there is plenty of range for volume adjustment. This is truly a superb combination.



The K812 is slightly less successful, though still enjoyable in its own way. Like the Focal models, this is a more sensitive headphone and thus suffers from a bit of background noise. It also gets moderately loud even on the lowest volume setting. Looking beyond those issues (or compensating with DAC volume adjustment) reveals a punchy, articulate, incredibly fast sounding headphone that excels with classical, jazz, and acoustic material. I was actually surprised that I could set aside the background noise and fully enjoy these genres - sparse arrangements have less tendency to hide the noise like more complex music would. Note that my K812 has been modified, replacing AKG's cheesy flexible printed wire assembly (FPWA) which carries the signal from the headband to the drivers. Very thin pure silver wiring was routed through the headband, along with a corresponding balanced cable to fully balance the connection. The FPWA was unreliable which is the initial reason for the mod, but once I heard the finished result I was blown away by how much better it sounded. The HA-300 may not technically be a perfect match but the combo still ends up sounding pretty fantastic.


Using an original TH-900 (stock) as well as the TH-X00 (in Mahogany, upgraded with Lawton Audio level 1 mods and angle pads), I was surprised by the blackness of the background. For some reason these low impedance, easy to drive cans, which I normally prefer via solid-state amplification, pair exceedingly well with the Cayin tube amp. As with some of the other pairings, it is perhaps not the most technically accurate sound, but there's a sense of emotion or soul in there which really speaks to me. Bass thump is killer, midrange very open and beautiful, highs controlled yet extended. The TH-900 gets a little loose downstairs but I think that is a property of the headphone itself more so than the amp. The modded TH-X00 actually sounds more balanced and just overall superior to the more expensive TH-900, which is tons of fun but not always something I'm in the mood for. Again, I would have never predicted this outcome, but it really works. Volume control is not an issue here whatsoever.


I tried LCD-2, LCD-3, and a bit of LCD-4 with the HA-300, and all made excellent pairings. I gravitated most towards my LCD-2 (non Fazor), where the HA-300 imparted a stunning sense of top end energy. Not sure I've ever heard the LCD-2 sound more spacious and open. LCD-3 (also pre-Fazor) was excellent as well, with a more neutral, linear sound and beautiful tone. Instrument placement on the LCD-3 was particularly well done, though LCD-2 was no slouch either. In both cases I consider the resulting sound to be about the best I've heard from these particular cans. I spent a little time with a first-run LCD-4 and it was jaw dropping as well - crushing dynamic swings and thoroughly engaging midrange. I've always passed on the LCD-4 but this particular pair, matched with HA-300, made me want to own it.

Unfortunately my Meze Empyrean arrived just a short time after I had already shipped out the HA-300 review unit, so I never got to pair those two. I suspect (and have heard from multiple friends) that this is a killer setup, but I can't confirm for myself. I did try various Grado, Audio Technica, and beyerdynamic headphones with generally solid results, but since I don't love these headphones or use them on a regular basis, I'm not really confident in describing the result compared to other top-level amplifiers I have on hand. I'll just say that for 90% of the headphones I tried, the result was up there among the very best performance that particular headphone has ever displayed - which means the HA-300 is doing something right.

Final Thoughts
As you can tell, the Cayin HA-300 doesn't necessarily have a consistent sonic signature that applies to every headphone it drives. In some cases the result is a bit warmer, somewhat forgiving and "fun", while other times it seems exceedingly neutral and clean. And at times it imparts a lovely midrange focus that I end up falling in love with.

I initially thought it paired best with higher-impedance cans but after trying out a dozen models (give or take) I don't really find a specific pattern. I love it with the planar magnetic Audeze and HiFiMAN designs. It is excellent with 300 ohm Sennheisers. But it also somehow loves the Fostex TH-X00, so I don't really know what to make of it. The Focals and K812 were probably the weak points but even so, I found myself mesmerized regardless of their faults. The only time I actually disliked a pairing was the HD660S, which is definitely more a function of the headphone (and its value relative to the old HD650) than the amp itself.

Without rambling on even longer, I will point out that the HA-300 is very much impacted by the source pairing. While Cayin's other tube amp, the HA-1A mk2, is rather forgiving of source, the HA-300 demands as good a DAC or player as you can possibly find. I realize people in the market for a $4K headphone amp likely have the means for a really nice source, but it's just an observation I wanted to touch on.


In the end, Cayin's HA-300 is quite possibly one of my all time favorite amps. It took me on a wild adventure, exploring various headphone pairings and the sometimes unique soundscapes possible with each. I definitely rank it up there with top caliber amps from Eddie Current, Donald North Audio, and Apex, while noting that the Cayin is significantly less expensive than top models from those firms. Not that a massive $4K amplifier could ever be considered "affordable", but it is a relative bargain in comparison. I would have a very tough time choosing if I were in the market for a reference tube amp right now.

I did not tube roll, nor did I have a matching pair of speakers on hand which could be driven by the Cayin's 8 watts per channel. So I didn't even fully explore the capabilities of this beastly amp. But from what I did experience, this thing is clearly a winner, and absolutely worth auditioning if the opportunity presents itself.



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About a year and a half in, and I'm still loving my HA-300! Got it paired with the highly recommended Psvane ACMe 300b (need 100-150 hours of min burn in) and the rare NOS Sylvania 6SN7W metal base tubes, as well as NOS GE 22DE4 rectifier tubes. I have a strong, full body sound with excellent extension top to bottom with very fast transients, great instrument separation and soundstage! It's also dead silent with deep blackness on my Audeze LCD-3!

Rest of the system: PS Audio Power Plant 3 power regenerator with Audioquest Thunder power cable, desktop computer -> Sablon powered USB 2020 - > Chord HUGO TT2 -> Morrow Audio MA6 with Furutech CF601/CF602 XLR ends -> Cayin HA-300 -> Audeze LCD-3
I do not recommend Cayin nor this amp. I rolled brand new WE 300B tubes in it and it failed the same day. One might assume the tubes were faulty but they were RMA'd and tested as a perfect pair. Cayin on the other hand has not respected my warranty with the excuse that I rolled tubes other than the ones it came with.. The manual literally describes which tubes the amp is compatible with - if one can't trust the amp with tube rolling it shouldn't be advertised that way. It's been a month and they won't RMA. I can't find anyone local to fix it. Total Nightmare. Do NOT trust this company or their dealers or distributors. Never had a customer service experience this poor in my entire life. And for a $4000 product. Buy elsewhere!
Yossy96- You probably just blew the fuse by accidentally inserting the 3rd party tube by pure bad luck. This technically could happen with any tube amp.

Easy fix, just replace the fuse with a new one (I believe it’s called a blo slo). Should be located behind the amp.