Cayin C9 Review

Cayin Audio C9

Sound – Tubes

Class A

As we’ve just seen Class A is the most refined and precise one with the best timbre, detail and decay. In tube mode you can add tube smoothness to this, but not overly so. You get just enough of warmth and smoothness to make it relaxing, easy on the ear and extremely musical.

It’s the typical tube tuning as so many people (me included) love. Who doesn’t love the extra sweetness and softness? Body-wise the tube output in Class A is lighter (sounding) compared to that in Solid State mode, but you in exchange get gorgeous timbre with lovely decay and softness.

The treble section here is very soft and easy-going on the ear, so take this into account when choosing your ear- or headphone you want to listen to.

Pace-wise you lose a bit in regards to the solid state mode, but that’s not surprising. In return you get improved decay, timbre and note extension.

If you like a more analogue, old school type of sound and/or tube smoothness and richness, this setting is one you will be listening to a lot.

Class AB

To me the tube Class AB setting is the least refined of them all. You get the more big and direct approach from the AB but with the softness of the tubes. Think body and presence in a slower, fuller presentation.

It’s not the combination with the best speed, dynamics and precision if you ask me. You get the tube warmth combined with low end weight and a slower yet more present top end. It’s a more condensed type of sound with less spaciousness and clarity. The mid part here not he most refined or articulated.

That being said, there are some headphones and earphones that work well with this specific tuning, and it’s all about personal preference in the end.

Cayin Audio C9

Sound Balanced  vs Single Ended

Both outputs are excellent and they show the differences in sound as we have described them so many times before.

Again, there is no best between these as they both have their own advantages and characteristics. It also strongly depends on the ear- and headphone you’re using as well as the type of sound you’re in the mood for. At home I tend to often go for balanced, where I on the go – when there’s more noise – prefer the single ended output.

The single ended output sounds fuller and more direct, where the balanced output sounds softer, often lighter but more spacious, extended and refined. Vocals are great with both outputs

Pre vs Line

Be very careful when switching between these settings, and make sure your volume dials are always at zero to start with. I on one occasions (mea culpa) almost blew my ears out, so check twice and put in/on your ear/headphones.

In pre mode with sensitive IEMs hooked up to the balanced output, you will hear some light noise but as aid earlier, it’s not so that this will bother you during music playback, unless there’s a long silent passage or you listen at an extremely low level.

When on-the-go I haven’t really used the pre setting and I just use the C9’s volume control, but at home at the office, I almost exclusively used the pre mode with my desktop source (with volume control).

Sound-wise it’s difficult to say if there is a difference between pre and line, though I seem to find the Pre mode more powerful sounding, something which combined especially well with full sized headphones.

Cayin Audio C9

IEMs & Headphones

I have listened to the C9 with so many different IEMs and headphones that it’s impossible to describe all possible combinations. The most important thing to remember is that one of the different tunings will perfectly match the ear or headphone of your choice.

I haven’t found one specific combo I like more than another one, simply because the C9 allows you to tune the sound to the characteristics of the ear/headphone. It’s the perfect amplifier!

The C9 seriously impressed me with full sized headphones, especially as Cayin is marketing this as a portable amp mostly for IEMs. The only two headphones I didn’t really fully like the C9 with were the HD800 and the HE6SE, but for the rest you actually get really good results. Headphones such as the Empyrean, LCD2c, Arya sounded excellent from the C9. (Though do take into account my earlier comment about the C9 vs high end desktop amps)


Thinking about the competition there are only two units that come into mind. First is the ALO Audio CDM, but that’s not available anymore and then there’s the Chord Electronics Hugo2, but that’s actually a DAC(/AMP) and not an amplifier.

Going over my inventory, I really don’t have anything that directly compares to the C9, a high end portable amplifier. And that’s probably also one of the reasons why Cayin has launched this device now.

Cayin Audio C9


I wasn’t really sure with what Cayin was planning with the C9, but I have to say I like it a lot and more as I expected.

The bad? Well there is the high end price tag but at the same time you get a very versatile amplifier, with great sound quality. And not only is it excellent for on the go, but it’s also a great desktop amp. Then there is the size as it for a portable unit is quite chunky, but as a desktop amp, it’s incredibly small.

Performance-wise the Cayin C9 excels and delivers what it promises: a reference, high end sound. And it doesn’t stop there. You get four completely different sound signatures, balanced and single ended in- and outputs and a dedicated pre-mode. That’s simply impressive!

Some people will complain that it’s an amplifier only, but I feel that this is one of its strengths. As it’s an amplifier only – with rechargeable and replaceable batteries – its life time compared to portable devices is extremely long. And as it performs so well, I can easily see myself and many other C9 owners use this C9 amplifier in our desktop setups for many years to come.

Looking at it like that, we can only conclude that the Cayin C9 is a great reference amplifier. If you’re in the market for an amp (transportable or desktop) that can handle almost everything and which offers you a multitude of sound signatures on top of that, the Cayin C9 should really be the first amp to look at.

4.4/5 - (185 votes)

Lieven is living in Europe and he's the leader of the gang. He's running Headfonia as a side project next to his full time day job in Digital Marketing & Consultancy. He's a big fan of tube amps and custom inear monitors and has published hundreds of product reviews over the years.


  • Reply March 16, 2021


    Um the broadway seems very similar in price, its battery powered amp with no dac. Seems like a pretty obvious comparison.

    • Reply March 16, 2021


      If you read both reviews you will have noticed a different writing style. That’s right, different reviewers. So um, these units are in different countries 😉

      And the Broadway isn’t really (trans)portable, is it? It’s a very special niche

  • Reply March 17, 2021


    How true is shaping sound by ‘battery rolling’, is that a thing?

  • Reply June 19, 2021

    Tim B.

    What be the Best DAPs to pair with the Cayin C9 at this time.

    • Reply March 6, 2023



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