Review: Cayin CS-300A tube Integrated Amplifier

Review: The Cayin CS-300A is an exotic tube amplifier, if only because of its limited output power - but an extremely pleasant one.
5/5 - (1 vote)

Searching for the string “300B” is now triggering gravitational waves in the filter bubble of my Googleverse. If you have an affinity for tubes, you can hardly avoid the legendary triode. Unfortunately, it’s not that easy in everyday testing to get your hands on an amplifier equipped with these tubes. That’s why I’m particularly looking forward to testing the Cayin CS-300A (price: 3,980 euros; distribution: ).

I created the prerequisites for this test about half a year ago. I replaced my Spendor D 9.2 loudspeakers with a pair of Horns FP12 (7,000 euros). The Polish massive hum with its 30-centimeter cardboard bass and the mid-high horns integrated in the cast baffles achieve a characteristic sound pressure of 93 dB/W/m. Enough to achieve decent volume with the not exactly lavish eight watts of output power per channel that the Cayin CS-300A delivers.

Which brings us to the basic case of most 300B amplifiers. The 300B triode was introduced in 1938. Back then, single-ended class A circuits were common in amplifiers. If you use a 300B in such a circuit, there is a maximum of 20 watts of power in it. That was enough in the 1940s in connection with horn loudspeakers in the format of an American side-by-side fridge-freezer combination for filling entire cinema halls with sound. However, the lifespan of a 300B running under full load is manageable. Unfortunately, rare NOS (New Old Stock) examples of the 300B are worth their weight in gold these days. And even high-quality specimens from new production cost serious money. That’s why most manufacturers limit themselves to teasing six to ten watts out of a 300B. This significantly increases the service life of the tube and reduces the resulting distortion to a HiFi DIN-compliant level.

Why would you buy an amp that uses a 300B as the output tube? The reasons can be very different. For some people, nostalgia for technology plays a role. I can definitely understand the fascination of such a tube , where you can literally see the amplification in the form of the glowing heating wires. It’s a bit like driving a vintage car. Of course, modern cars are faster, more economical, more comfortable and safer. And yet it is incredible fun to drive a car where the technology is still understandable and can be experienced in the truest sense of the word.

Leuchtende Triode 300B

Other people cite tonal aspects. You have to relax a bit here. Without throwing myself into the camp of hi-fi esoterics: it only makes sense for me to argue with them when the measured values ​​have been checked for their significance with regard to the sound effects. In my opinion, this applies in particular to distortion values . In terms of measurement technology, tube amplifiers usually perform worse than transistor amplifiers. But honestly, what good is an amplifier with a distortion factor of 0.0001% that still doesn’t sound good? Especially since there is hardly a speaker that generates less than 1% distortion. And the listening room adds its mite. On the plus side, tube amplifiers such as the Cayin CS-300A also have that the distortion spectrum is harmonic  is distributed and is therefore usually perceived by the ear as less (more) disturbing than inharmonic spectra. That’s why – at least to some ears – higher THD values ​​from tubes sound better than lower THD values ​​from transistors. And with the “objective” measured value distortion we ended up in subjective realms.

But let’s stop at this point, postpone everything else to the listening test and first take a closer look at the Cayin CS-300A. The physique of the device is impressive. With a width of 420 and a depth of 382 millimeters, it weighs 26 kilograms. A good part of the kilos goes on the powerful mains transformer, but the output transformers also have a significant share of the total weight. Most tube amplifiers need output transformers in order to adapt the inherently higher internal resistance to the low impedances of loudspeakers. The Cayin CS-300A’s transformers are designed in such a way that speakers with four, eight and 16 ohms can be connected to the amplifier. Corresponding taps can be found on the back.

Das Lautsprecherterminal des Cayin besitzt Abgriffe für 4, 8 und 16 Ohm

At the back there are three pairs of cinch sockets for connecting high-level sources. Another pair of cinches serves as direct access to the power amplifier, the volume control is ignored here. Speaking of which: the volume control sits in the middle of the front and runs pleasantly well. You can’t say that about the input selector switch, but the fact that it wobbles a bit is unfortunate for the testers: I received a demo device as a sample that has already had quite a few trips under its belt.

The active input is indicated by LEDs on the front. In addition to these LEDs, there are two more that are labeled “0 dB” and “-3 dB” and indicate the degree of negative feedback used. This can be switched using the remote control and has a serious impact on the sound. More on that later.

Die Rückseite des Cayin CS-300A

Otherwise there is a headphone jack. And the big, round pointer instrument at the top between the tubes. This, along with a small rocker arm and a recessed potentiometer shaft next to each 300B, is used to set the quiescent current of the tubes. Simply press the rocker arm and use a screwdriver to adjust the potentiometer so that the pointer is in the middle. A simple solution, but in case of doubt better than the use of an automatic quiescent current control, which is controversial in terms of sound. Yes, it’s a tube thing, but the operating points of tubes just change as they age.

Das Zeigerinstrument des Cayin CS-300A

Cayin CS-300A in the listening test

Enough with the technology, now it’s time to listen. And my first thought is: What, that’s only supposed to be eight watts? In fact, the Cayin CS-300A looks like it is very well fed. With the level control at nine o’clock, my horns play at a very decent volume. And it gets louder. All in all, the Cayin is already much more than high room volume, but even further beyond that is quickly over. Nevertheless, with its eight watts, the CS-300A plays much louder than I usually hear.

My second thought is: I like hearing that! Clearly, that is a completely unqualified statement. Nevertheless, I sit in front of the plant and am tied up. Amy Antin’s album Just for the Record is up and running. I like the sparsely produced recording, which transports a lot of atmosphere and conveys a quite intimate mood through its immediacy. Through the Cayin CS-300A, the singer sounds closer than I’m used to. In general, everything seems a little bigger, closer, more secluded. The bass is soft, warm, nice and round and full. This is exactly what is meant by a warm sound. In other words, what many expect from a tube. It’s beguiling.

After a while, however, I get angry. I’m not really satisfied with how the Cayin CS-300A conveys Ms. Antin’s articulation. I’m missing some clarity. There seems to be a gap above the root. There is a little lack of speech intelligibility here. It’s all beautiful, no question, but maybe a little removed from the musical truth. A look at the LED light band on the front of the Cayin CS-300A gives me an indication of what could be the reason: The orange LED under the “0dB” label lights up. The two 300B work unbridled, completely without negative feedback. More tube is not possible.

Cayin CS-300A - Röhrenverstärker von vorne

The remote control irritates me at first: The button for switching the negative feedback is labeled “nfb”. Ok, “negative feedback” – that’s what counter-coupling means in English. One push of this button… and something dramatic happens.

Die Fernbedienung des Cayin-Röhrenverstärkers

First, the playback becomes quieter. Logically, part of the amplification is now “sacrificed” to the negative feedback. At the same time, the stage jumps backwards and the image, which previously seemed quite large, jumps to normal size. And at normal distance, the stage now starts at about the baseline between the speakers. In a direct comparison, the whole thing seems more sober at first, but ultimately more correct: singers and instruments are clearly separated from each other, the gap in the vocal reproduction has disappeared and the lyrics are fully understandable again.

The bass reproduction

In the following, the LED under the “-3 dB” label lights up. The bass reproduction also shows that the decision was the right one. Because when restrained by a touch of negative feedback, low tones come out less lush – they are now in the neutral range – but sound much more clearly contoured and controlled. The combination with the Horns loudspeakers is obviously a stroke of luck, in any case the Cayin CS-300A delivers a bass that you could hardly wish for better. It goes deep and sounds controlled at all times. It lies in a range between powder-dry and full-bodied-soft – i.e. about semi-dry. This is what I think is ideal for playing acoustic instruments. The bass strongly reminds me of the performance, Line Magnetic LM-150IA (5,000 euros). The powerful Line Magnetic (2 x 100 watts) is of course much less complicated when it comes to selecting speakers. For that you have to live with a slight hum and a decent background noise, which can at least be audible on high-efficiency loudspeakers.

Cayin CS-300A mit Röhrengitter

It Don’t Mean A Thing…

I discovered big band jazz in Berlin’s swing scene. You can also dance Lindy Hop to it. In this respect, you will certainly forgive my soft spot for the somewhat exotic pairing of Tony Bennett and Lady Gaga . This collaboration has resulted in two fairly traditional big band albums: Cheek to Cheek and Love for Sale . Especially the latter album offers a wide range of different pieces and above all a lot of acoustic instrumentation. And no matter whether drums, double bass or piano set the rhythm, the Cayin CS-300A reproduces it cleanly, with clear transients and, if necessary, with a lot of assertiveness. And it has swing: the energy of the music comes across as intoxicating. I’m excited.

As crass as that sounds – I don’t immediately have the impression that I have to make big compromises compared to my multiple more expensive combination of preamplifier EAR Yoshino 868PL (6,000 euros) and power amplifier Bryston 4B³ (8,000 euros). Mind you – spontaneously. In comparison, the combination, which is around 10,000 euros more expensive, shows that more is possible in terms of grip, bass, details and precision. But the bottom line is: if I didn’t know, I wouldn’t miss it. The Cayin CS-300A simply sounds convincing.

mids & highs

With the negative feedback switched on, the Cayin CS-300A also passes through as neutral in the mids. The voices of Tony Bennett and Lady Gaga are a great contrast. Musically, 85-year-old Tony Bennett has always been at home with jazz, while Lady Gaga is a powerful-voiced pop icon. Whereby she proves here that she also masters the quiet tones. Both are really great in a duet. And the Cayin CS-300A neatly separates the facets of both voices, makes the peculiarities audible, but doesn’t “dissect” them. In the duets, these two different voices sing together and not against each other, with the 300B amplifier making the subtle nuances audible at all times.

300B-Triode im Detail

Jazz swing has me wanting more and I switch to an old recording by the Oscar Peterson Trio . The tracks to Action (Exclusively for My Friends)were recorded in 1963 and 1964 in the studio of Hans Georg Brunner-Schwer in Villingen. Recorded more as rehearsal recordings for a subsequent private concert for friends, there is a ease and joy in playing here that is hardly known from the otherwise rather virtuoso-experienced and concentrated playing Peterson. And the Cayin CS-300A literally beams me into the recording. I have no idea how that works. Through him, the music seems so plastic and concrete, as I have seldom heard over “modern” electronics on this recording. One possible explanation: tube amps work well with recordings that were also made with tube electronics. In fact, I think that’s pretty logical: In the past, sound engineers didn’t hear any worse than they do today. And ideally they also had the original as a benchmark. At that time they certainly mixed the recordings in such a way that they sounded optimal with the electronics of their time. So if you’re listening to such recordings today with similar electronics, you should be pretty close to what was intended at the time of production.

This is not to say that the Cayin CS-300A is only good for old recordings. I want to know and switch to electronic music. The Chemical Brothers may not be all the rage now either. But their album Born In The Echos is part of my favorite listening repertoire. And that also works excellently with the Cayin CS-300A. The intro of “Sometimes I Feel So Deserted” draws my attention to the treble. It pings, chirps and screeches quite a lot. Nothing unpleasant or sharp here. Funny, I’ve hardly thought about the treble while listening. It’s just there, doesn’t push itself to the fore, supports timbres. The highs don’t seem loud, but rather more subtle/mild, but are still rich. Amazing how different tube devices can sound. The Audio Hungary Qualiton A20i (4,500 euros), for example, played rather powerfully in the highs and tended to be wiry.

Oberer Teil der 300B-Triode

The bass is also right in this piece. It has pressure, substance, contour – that’s exactly how it should be. I would love to hear how this amp sonicates a party with a real high-efficiency speaker. Should I think about buying corner horns?

The headphone jack

Out of consideration for my neighbors, I’d rather briefly go into the headphone connection of the Cayin CS-300A. It’s definitely not a nice goodie, but to be taken damn seriously.

Kopfhöreranschluss des Cayin CS-300A

I’m currently listening to the Austrian Audio Hi-X65, a pair of professional, open-back over-ear headphones designed for mastering. The Hi-X65 is trying hard to become my new favorite pair of headphones. And what this very neutral listener does in connection with the Chinese tube amp is breathtaking. The Cayin CS-300A breathes exactly that nuance into the sound that I miss with the very neutral RME-ADI-2-DAC FS when I connect the headphones directly here.

Cayin CS-300A – classification and comparisons

How should I rank a small power amplifier like the Cayin CS-300A in the competition? The demands it places on the loudspeakers alone are completely different than with “normal” amplifiers.

Nevertheless: The powerful (2 x 100 watts) Line Magnetic LM-150IA (5,000 euros) is less complicated in terms of loudspeaker selection. You just have to live with its subtle background noise. Otherwise both amps don’t even sound dissimilar. This also makes it clear that the Cayin is less ethereal than the very sensitive Audio Hungary Qualiton A20i (4,500 euros), which sets other tonal accents. A TAC V-88 (5,000 euros), on the other hand, also has more power than the Cayin, but sounds clearer (in a very pleasant way).


The Cayin CS-300A is an exotic tube amplifier, if only because of its limited output power – but an extremely pleasant one. In my opinion, anyone who chooses the Cayin will achieve an extremely high degree of satisfaction with their system if the general conditions and especially the loudspeakers play along. You are out of the race for the latest technology and instead belong to the club of those who listen with a pair of the legendary 300B.

If you combine the CS-300A with the right speakers, you will experience a sound that is very harmonious. You can experience really magical moments with him, especially with older recordings. And on cold, wet autumn days, simply switch off the negative feedback and enjoy the uninhibited, warm, comforting tube sound. I won’t tell you either…

The Cayin CS-300A is characterized by …

  • an overall enormously coherent performance, one simply likes to listen to him. The Cayin CS-300A plays coherently and – at least with activated negative feedback – is tonally fairly neutral.
  • Little power, which in many cases is absolutely sufficient in connection with loudspeakers with a higher degree of efficiency.
  • a semi-dry, wonderfully “swinging” bass that harmonises great with acoustic instruments, but is also good for synthetic bass – as long as the speakers have a decent level of efficiency.
  • clearly defined mids, which, as far as details and microdynamic gradations are concerned, come across as very subtle and always sound lively and fun to play.
  • a slightly reserved high tone, which nevertheless offers a wealth of information. Nothing imposes itself here, everything is simply there. The fact that perhaps “a few more overtones” than usual are involved is only noticeable in the pleasantly clear, powerful timbres.
  • a very clean spatial image. The Cayin CS-300A depicts what is happening in a stable manner, with sharp contours and high localization sharpness. This also applies to the depiction of the recording space, which is drawn realistically in terms of width and depth. The stage begins roughly at the baseline between the speakers.
  • special synergy effects with older recordings. In some cases, the Cayin CS-300A surpasses itself here – especially when it comes to the spatial illusion.
  • a great graded fine dynamics. The coarse dynamics are limited due to the manageable performance. If you want to experience the full dynamics of a large orchestra, you need very efficient loudspeakers.
  • the absence of background noise. Should be self-evident, but unfortunately it is not.
  • the possibility to switch off the negative feedback and indulge in the enjoyment of proverbially beautiful tube sound.


  • Model: Cayin CS-300A
  • Concept: Integrated tube amplifier with 300B components in single-ended class A circuit
  • Price: 3,980 euros
  • Dimensions and weight: 42 x 38.2 x 19.5 cm, 26 kg
  • Inputs and outputs: 3 x high level, 1 x direct input (RCA); Stereo speaker terminal for connecting 4, 8 and 16 ohm speakers
  • Power: 2 x 8 watts (RMS), at 4, 8 and 16 ohms
  • Power consumption: 160 watts
  • Miscellaneous: switchable negative feedback 0 dB/-3 dB, quiescent current setting with built-in pointer instrument, remote control
  • Guarantee: 2 years