In our review today we cover the new Cayin HA-300MK2 which is a 6W capable high-end SET tube headphone amplifier and speaker amplifier. It is priced at $4399.
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The original HA-300 from Cayin was a desktop amplifier I have encountered on more than a few occasions at some of the trade shows before Covid was a thing. Sadly, it never arrived here for review.
From the brief time I did spend with it, the sound was delightful. However, I was simply not in a position to dive into and listen in more detail to complete the picture.
So the arrival of the new flagship HA-300MK2 integrated headphone and speaker amplifier for review gives me an ideal opportunity to explore Cayin’s true legacy product range, their big rigs, or desktop amplification products.
It is also an ideal year also to assess stuff like this with the recent launch of some superb headphone tube amps such as the Feliks Audio Envy and laterally, the new dCS Lina solid-state headphone amplifier. All of them, including the HA-300MK2, are competing for the high-end audiophile’s attention.
Tech Highlights
The HA-300MK2 is a transformed coupled Class-A headphone tube amp for the purists. This is also a single-ended triode amplifier for speakers usually referred to as SET or SETA as opposed to a hybrid tube amplifier or one using a push-pull design.
SETA means a design that uses a single-triode tube per channel that allows the signal to stay intact throughout rather than a push and pull design that splits the plus/minus of the signal mid-path via a pair of tubes, (or more), and then reforms to complete its output.
The general consensus is that due to this topology, the SETa is generally a smooth sound signature but more limited in potential power because you can only use 1 output tube. A push-pull is more powerful given you can ramp up the number of tubes per channel but for some, the SETA smoothness is lost as a result.
Driver Tubes
The amplification itself is handled in two distinct phases and both are underpinned by a set of tubes, driver, and power. The driver tubes are a pair of matched Tung-Sol 6NS7GTB dual-triode tubes.
These are a favorite among desktop tube amp fans, primarily for good low-noise performance. However, they are also valued for their ability to tease out some improved body and richness in the amplification tone to deliver a very natural sound signature.
Power Tubes
The HA-300MK2’s 300B output or power tubes are the calling card, however. Originating as far back as the 1930s and originally developed by Western Electric, this is a large directly heated triode tube and one that ties in nicely with the purist or minimalist approach of the HA-300MK2 topology.
These are never cheap tubes to roll, especially a matched pair with some of the headline options costing as much as $700 in the open market.
Now, from what I understand Cayin deliberated the potential of a set of FullMusic 300B tubes but opted for a matched pair of Gold Lion Genelex PX300B tubes instead as it better matched their intended ‘house sound’.
Genelex is now under the ownership of the New Sensor Corporation combined with Electro-Harmonix in the US which also carries a lot of other big-name tube brands such as Mullard and Svetlana.
Cayin refers to the PX300B tubes as a good all-rounder or a ‘common man’ upgrade 300B tube and one that remains faithful to the typical natural sounding 300B sound signature.
2-Box Design
Externally, one of the unmistakable aesthetical features of the HA-300MK2 is the split between the power supply and the amplifier itself.
Cayin calls this their two-box design and though it is by no means an exclusive design approach to the company it does allow them a degree of freedom to design a rectification stage whilst reducing the potential for electrical interference.
Since the HA-300MK2 is a pure SET design, the PSU is driven by a quad set of NOS RCA 22DE4 rectifier tubes. The choice of tubes and overall physical design look very much like the original HA-300’s PSU and given they have independent wiring and functionality you do not need to have them matched.
Unmatched and with a 5-10 year life cycle should also mean a fairly low-cost maintenance budget if you decide to roll or replace these tubes.
Impedance Selector
The HA-300MK2 also features an impedance control option which is something I am seeing more and more now, particularly on tube headphone amplifiers. This will be familiar to the MK1 owners though the target impedance has been tweaked a little more to suit a lot of headphones these days that have low impedance values.
Typically, you can view this as an adjustable ‘tap’ through which you can directly control the precise output voltage level and how much power you can release to the connecting headphone. For this particular amplifier, Cayin has introduced a 3-stage impedance with ranges or parameters up to 64Ω, 250Ω, and 600Ω, (balanced matched).
Now, this is not to be confused with a dB gain function similar to what you might find on the back of something like the solid-state Violectric V590. Rather, this is about optimization and delivering enough voltage headroom to ensure both the dynamic range of the paired headphone and its performance are properly driven and natural sounding.
Personally, I found a lot of planar headphones to work really well on the HA-300MK2 high impedance selector where the voltage output is likely to be at its strongest.
However, this is not cast in stone. With some midrange load headphones, you might find yourself switching between one setting or another depending on your preference and the headphone’s current/voltage demands.
Performance Numbers
At various loads, the Cayin HA-300MK2 offers a very powerful output range for both balanced and single-ended headphone connections. Do take note, that solid-state principles of lower impedance equal more power do not apply here. With a SET of this type, the lower the impedance the lower the power output rating.
For 4-pin XLR balanced, its 6W on the high impedance settings for loads up to 600Ω. From there, switching down to medium will give you 1500mW up to 250Ω, and on the low impedance selector it’s 2W up to 64Ω.
The HA-300MK2 also offers 4.4mm balanced and SE via a 6.35mm output port but the numbers drop a little here in comparison to the 4-pin XLR output at a maximum of 5.4W for 4.4mm and 5W for SE on high impedance. Still, plenty of headroom there despite the minor drop.
For speaker output, there is no pre-amp capability inside the HA-300MK2 but it can deliver a reasonable 8W to both channels for speakers up to 8Ω impedance levels via dedicated left-right binding posts.
Design
This is an absolute beast of a headphone amplifier, both in terms of engineering precision and yes, weight. It is probably one of the most exquisite designs I have seen to date.
At 29kg is also one of the heaviest gear I have ever handled for review but, you can thank the powers that be because it is split into 19kg for the amplifier itself and 10kg for the PSU. That makes it more manageable for moving around piece by piece without fear of putting your back out or dropping it.
The HA-300MK2 comes in two finishes, classic silver, and a more aggressive black alternative, and both with 4 solid silver-finished isolation columns at the base to keep them fixed firmly in place.
Both options are finished with a solid brushed aluminum-magnesium chassis, overlooking transformer towers, and some seriously thick and sturdy 13.5mm matching black anodized front windowed panels for the beautifully engineered I/O suite.
You will not find a single hollow knock from the HA-300MK2 housing, anywhere. It feels incredibly robust though, of course, I would advise against testing that statement out too thoroughly.
The PSU is slimmer, and uses Cayin’s in-house design toroidal transformers but is otherwise finished in the exact same manner. Aesthetically, it fits in seamlessly with the main amplifier.
You do not have to place it right beside if space is a consideration, however, if you, do I find it naturally suits the Weipu power coupler cable’s inclination to curve naturally from left to right.
One thing to note is that the solid custom-made EI transformers housed on both units are to the rear, where all the weight is also. If you are lifting, do so from the rear to maintain your balance as they could unexpectedly tip.
Finishing
Accents on both units are gold and silver with the gold primarily for the Cayin monikers on both the PSU and the main amplifier as well as 4.4mm contacts. The silver is primarily for the mechanical switches on the front plate and they do help them to stand out a bit more making it easier to locate and operate.
The HA-300MK2 and PSU also come with similarly finished black tube grill guards. They are more expansive compared to the low-profile versions on the Envy but with a full rail protection front to back and enough space on top for them to breathe. They are also detachable should you wish to use the amplifier with the tubes exposed, depending on your preferences.
The analog-style VU meters behind those circular clear screens are gorgeous, even more so when turned on activating a mild glow from the rear lighting system to draw attention to their endless movement during playback. That glow is complemented by the HA-300MK2’s PSU power button which is wrapped with a similarly colored LED ring that lights up when turned on.
I/O
The I/O on the HA-300MK2 is a lot simpler in terms of options compared to competing amps such as the Auris Audio HA-2SF and the Feliks Audio Envy. It is not bequeathed with multiple input options with no corresponding input selector either to the front and with no additional pre-amp output.
However, what it does have is a set of proper speaker outputs (screw or banana type) to connect directly to your chosen speakers which is something lacking in the aforementioned competing amplifiers.
The analog inputs include a single set of balanced 3-pin XLR sockets, dual RCA single-ended sockets and to the far right a Weipu DC coupler for receiving power via the supplier cable from the PSU.
All options are very easy to understand with a clear separation of the analog inputs to the left and the speaker outputs to the right. The spacing is good also so cables should not be pushing against each other either.
To the front, the HA-300MK2 is all about the modern headphone audiophile with the inclusion of a 4.4mm balanced PO, as well as the more traditional 6.35mm and 4-pin XLR unbalanced and balanced PO.
Controls
A big amp also means plenty of space on those thick front plates for a wide range of controls and display information. The HA-300MK2 power switch itself is located on the individual PSU rather than the amplifier.
Controls include some fairly durable switch selectors with a decent amount of movement resistance for the PO of choice and the impedance selector to the far left. Just above the potentiometer, there are selectors for your source and whether you are outputting to headphones or speakers.
Volume control on the HA-300MK2 is via a JRC MUSES72320V electronic volume controller which is a popular Cayin choice and one you will see pop up across their product range.
The controller is tied in with a 41-step ALPS balanced potentiometer and one which is not too notchy and resistant either making it quite easy to control with a very linear attenuation curve.
Packaging & Accessories
The HA-300MK2 packaging is much too huge and slightly blemished from weeks of shipping and plastic wraps to properly display here in the review but suffice to say it’s a huge box and a heavy one at that. I would strongly suggest bringing some helping hands if you want to haul it up a few flights of stairs.
Inside, the amp is very well protected though the tubes are inserted in the amp which I am not a huge fan of. I would much prefer to see them in their own carriage boxes in case the grill comes loose and moves around from poor handling.
That being said, there is plenty of foam inside the grill and around the amp to give it enough protection for regular shipping. Aside from the copious amount of foam you also get a fairly thick and well-insulated but fairly lengthy DC power coupling cable to hook up the PSU to the main HA-300MK2 amplifier.
