The Course of Vacuum Tubes in Cayin Portable Personal Audio, and a Glimpse to the Future
Apr 11, 2024 at 5:35 AM Thread Starter Post #1 of 44
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The Course of Vacuum Tubes in Cayin Portable Personal Audio, and a Glimpse to the Future

In August 1993, Spark Electronic Equipment Co., Ltd. was officially founded in Zhuhai City, Guangdong Province, China. The company traded under the name Cayin since 2009 and gradually expanded into a High-end Audio manufacturer that covers the complete audio system, ranging from solid-state amplifiers, CD players, and audiophile DACs. Among different products, Cayin’s tube amplifiers have been particularly well-received within the audio community and that become our core competence.

The Dawn of Vacuum Tube in Portable Audio (2018 – 2020)

Audiophiles who are familiar with portable personal audio products are no strangers to the KORG Nutube 6P1 double triode Vacuum Tube by now. Cayin surprised the portable community when we debuted the N8 Digital Audio Player at Munich 2018 (May 10-13). This was our first project with KORG Nutube in a portable player, and possibly the first-ever successful implementation of the Nutube that allows users to handheld the device and walk around while enjoying the unique tonal charm and involving listening experience of the vacuum tube. On 19 September 2018, Cayin officially launched this groundbreaking DAP to unleash the R&D achievement in vacuum tube installation, anti-shock anti-vibration techniques, microphonic elimination, and circuit design to facilitate the KORG Nutube to perform satisfactorily, and the N8 DAP has quickly gained recognition from DAP and IEM users.

In the following years, one after another, other brands are applying KORG Nutube 6P1 products on the market. With the emergence of compact headphone amplification circuits constructed from discrete components, we have seen a large variety of traditional speaker amplifier techniques migrated into portable applications. “tube”, “solid-state”, “tube/SS hybrid”, “Class A”, “Class AB”, …. become buzz words in portable personal audio, and Cayin has our share in building up the norms of placing analog engineering into the lead position, and the “baijia zhengming” (the contention among a hundred schools) phenomenon created a great deal of "noise" and quickly formed a unique landscape to Personal Audio industry.

The HiFi industry has blossomed because it is an extremely subjective market where we respect and appreciate personal preference. Each listener has a different tonal preference and owns audio systems that are vastly different from each other, resulting in a different listening experience. This is a big challenge to manufacturers and brand owners because, while they adhere to the brand's understanding of the music playback and fostering their house sound, they must constantly learn from user feedback to avoid work behind closed doors.

Likewise, when we introduced vacuum tube sound to portable products for the first time, we spent a lot of time collecting first-hand feedback from users. Those who appreciate N8 tell us that they really enjoy the mid-range of the player, the warm and euphonic presentation lets them experience the emotion of the music in such an intimate way that they won’t experience solid-state alternatives; while users who don't like it described the N8 as ambiguous, lack of crispness and sparkling, and so on.

Unlike other brands who will pass down the flagship technology to the sub-flagship or mid-range product gradually, we jumped from flagship to entry-level model when it deemed fit. We passed down the portable vacuum tube technology to our entry-level DAP and rolled out the N3Pro Digital Audio Player on 17 August 2020. On top of having tube timber in the amplification circuit, we connected the vacuum tubes to the audio circuit in triode mode and ultra-linear mode, the alternative connections will generate different amounts of feedback, harmonic and output impedance, offering two distinctive vacuum tube sound signatures for the N3pro DAP.

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The second generation Vacuum Tube Circuit for Portable Audio (2021-2022)

Over the next two years, while listening to feedback from N8 users, Cayin continued to explore the KORG Nutube 6P1's circuitry and optimize the mechanical damping structure. By 20 January 2021, Cayin launched the renowned C9 portable headphone amplifier and created another benchmark in the history of KORG Nutube portable audio implementation. This is a portable headphone amplifier, a purely analog device without any digital audio capability. For the first time, we employed a pair of KORG Nutube to achieve fully balanced vacuum tube amplification in a large portable/small transportable form factor. According to the N8 DAP users, the C9 is a step ahead of N8 in the technicality departments: stellar dynamic, rapid transient response, and improved frequency extension on both ends. All these were credited to the revised NFB on the KORG Nutube timbre circuit in the C9 portable headphone amplifier. The high frequency and ultra-high frequency displayed, relatively, crispiness and stronger directivity. The midrange is not as warmish when compared to N8 but the leaner midrange also enables the soundstage to display more detail and sharper image, you can almost pinpoint the instruments. The overall presentation is more complete, especially in terms of pace, rhythm, and spatial perception.

This is Cayin’s second generation of KORG Nutube 6P1 circuit design in portable products and it is also a time for Cayin to deviate from the traditional “tube” timbre to make changes to better fit the listening preferences of portable users. The result is, to a certain extent, polarized. Audiophiles who have used “traditional” tube amplifiers for speaker setups say that this amplifier lacks “tube flavor”, while other audiophiles said that the KORG Nutube in C9 has finally delivered the "quality" of the high-end amplifier, and not as "muddy" as previous implementations.

Cayin took another step to refine our latest Nutube implementation and launched the N8ii Digital Audio Player on March 4, 2022. By combining the engineering of N8 and C9, we incorporate a matched pair of KORG Nutube 6P1 to deliver the first portable DAP with fully balanced vacuum tube amplification. As of today, this remains the only fully balanced vacuum tube amplification DAP in the market. We extracted a small paragraph from our N8ii official announcement

“Ever since we laid our hands on KORG Nutube 6P1, we have conducted a very thorough study to apply the “flat” miniature Double Triode in different circuit designs. We have gone through over 30 rounds of PCB with Nutube already, which roughly tells how exhaustive we are on this subject. Based on the feedback from dealers and users on N8 and C9, and our observations to market response in the past 10 years (Cayin entered the Personal Audio market in 2013), we adopted the Zero Gain Negative Feedback Loop circuit in the N8ii design. This will deliver strong current and impressive handling at difficult loads. We have adjusted the feedback loop carefully to enhance the transparency, transient, and extension that can rival the best solid-state circuit but yet remain warm and mellow.”

The N8ii was generally well received. We didn’t design the KORG Nutube to sound like a vacuum tube, it became a means in an audio device that delivers high-end audio performance. Unfortunately, we have also received even stronger critics complaining the vacuum tubes have lost their “soul”.

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The Gen3 Vacuum Tube Circuit for Portable Audio (2023-2024)

So we go back to the drawing board and reconsider our position from the ground up. The biggest difference between Personal Audio users and Home Audio users is that the latter build their system around one pair of speakers which has a specific sound signature that won’t change over time. On the other hand, a large percentage of Personal Audio users own multiple pairs of earphones or headphones, and the more voiced-out users quite often own a dozen IEMs/headphones, which means they are dealing with wider synergy options, more variations, and more adaptations to different sound signatures.

We detoured, but yet we were on the right track. Without the user's continuous feedback, without taking user opinions seriously, we might just stick with our one-way ticket in a technically profound Narnia and eventually drift away from the technological innovation capability that will revive the KORG Nutube 6P1 double triode vacuum tube to the next level.

September 4, 2023, is another milestone in Cayin’s Nutube journey and possibly one of the more important milestones in Cayin’s corporate history. We launched the N30LE, our 30th Anniversary Limited Edition Digital Audio Player. The Gen3 Nutube 6P1 vacuum tube circuit marked the return of the classic. For the first time, we have incorporated “Classic” and “Modern” dual vacuum tube timbre into a compact and sophisticated DAP circuitry.

When our users asked for vacuum tube flavor, high-end audio quality, and impressive technicality, Cayin delivered. The N30LE is a DAP with multiple timbres, and every timbre option is our attempt to deliver ultimate performance in its own right. In addition, Cayin has redesigned the analog circuit so that the tube timbres apply to all analog outputs, so we can now engage tube timber in the headphone, line, and preamp output of N30LE.

Cayin hears you, this is the DAP that will work fine with a wide range of IEMs, headphones, and music genres and this is our offer to the diversified timbre needs of Personal Audio users. The N30LE received unanimous recognition, saying this is the DAP that meets all their needs in one package. Even users with different personal preferences agree that the N30LE breaks a lot of barriers and limitations.

Similar to what we did with N3Pro DAP, we pass down the N30LE technologies to our mass market DAP so that we can maximize the audience who can enjoy the benefit of our R&D. Without any debate, we rolled out the N3Ultra Digital Audio Player on 8 April 2024. In this exercise, we have taken advantage of the dual tube timbre experience from N30LE and fine-tuned the Triode/Ultralinear options of N3Pro into the latest Classic/Modern dual tube timbre. The Classic timbre is thick, and warm, with rich overtones, best suited for vocal performances but weaker in dynamics and transients. The Modern timbre has a more open soundstage, with stronger extension at both ends and linearity. Thus, the naming follows the same definition as the N30LE, indicating consistency in sound presentation.

On the other hand, the N3Ultra tube timbre is also applicable to both headphone and line-level outputs, making it a complete implementation of the Cayin Gen3 vacuum tube circuit design.

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A Glimpse to the Future

However, is this enough?

The detailed recap on KORG Nutube is a side note, the focus of this writing is that the next generation of Cayin’s KORG Nutube 6P1 technology is around the corner, and the C9ii Portable Headphone Amplifier will be the Cayin product that will be empowered this technology. I know, we have received loads of inquiries on when and how will C9 receive a dual tube timbre update after we launch N30LE. The C9 and C9ii are extremely niche products in a vertical market, but Cayin will not let you down because our love and passion for high fidelity industry will drive us to do our best.

We have confirmed the overall circuit design of C9ii over-circuit, and we are in the process of miniaturizing the engineering prototype into something more practical and portable. Together with the subjective tuning stage, there will be probably six months or more before we can showcase the C9ii to the public. We have included several Industrial design drafts of the C9ii to give you some idea of what we are working on, and we sincerely looking forward to another round of recognition when we debut the C9ii. Yes, we are very confident because vacuum tube amplifier is our core competence and we have three decades of proven track record to endorse our claim.

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Apr 11, 2024 at 5:37 AM Post #2 of 44
Reserve for more Photo
 
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Apr 11, 2024 at 5:43 AM Post #3 of 44
This article is an English rewritten of a Weibo update from Thomas Liang, CEO of Cayin Audio. He has some very interesting discussions regarding the positioning and implementation of our vacuum tube DAPs with fellow Cayin users on our Wechat User Groups. To facilitate further discussion, he decided to document the milestones on how and when Cayin has developed our Vacuum Tube products on portable Personal Audio applications over the years. I find the article very useful as I have also been actively interacting with a lot of "headfiers" and we quoted previous Cayin products repeatedly during our exchanges. So I rewrote the article and made it available to all friends and users of Cayin Audio.
 
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Apr 11, 2024 at 6:25 AM Post #5 of 44
Please make the subjective tuning switches more obvious this time. When I first bought my Cayin C9 years ago I was hoping for it to have a profile similar to the recently released Ibasso PB5 Osprey nutube portable amp.

I find the difference on the C9-modes as being too subtle.

I still love the Cayin C9, because it is really an amazing desktop level transparent amp; does not compress the dynamics or staging at all!...But I would like a warmer (and possibly darker) profile option out of it.

Otherwise it'll be redundant alongside the availability of the C9.
 
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Apr 11, 2024 at 10:48 AM Post #7 of 44
Awesome post. Can’t wait!
 
Apr 11, 2024 at 10:50 AM Post #8 of 44
KORG Nutube 6P1 is from 2015. Can we expect something more advanced or is this the last generation of integrated tubes?
There are no other Nutubes, only one model. No plans for Korg to develop another one , it seems.

It’s the implementation that is key, not so much the age of the tube design/components.

There are myriads of amplifiers based on the same tubes and they all sound different.
 
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Apr 11, 2024 at 11:05 AM Post #9 of 44
Please make the subjective tuning switches more obvious this time. When I first bought my Cayin C9 years ago I was hoping for it to have a profile similar to the recently released Ibasso PB5 Osprey nutube portable amp. And I find the difference on the C9 available modes as being too subtle.

I still love the Cayin C9, because it is really an amazing desktop level transparent amp; does not compress the dynamics or staging at all!...But I would like a warmer (and possibly darker) profile option out of it. Otherwise it'll be redundant alongside the availability of the C9.

If you read the article, you'll notice that the C9 and N8ii shared one common objective: we didn’t design the KORG Nutube to sound like a vacuum tube, it became a means in an audio device that delivers high-end audio performance.

We couldn't make everyone happy, we have to position ourselves to maximize our profit while building up our brand and sharpening up our engineering/technologies, in other words, we must compromise.

The Gen3 Vacuum tube circuit is a big step along this line because when we have TWO tube timber (Classic and Modern) instead of one, we can satisfy a larger group of users, but in a nutshell, when we widen our coverage from making 70% users happy to making 90% users happy, unfortunately, some users will still be unsatisfied with our choice. After all, "we couldn't make everyone happy" is the inevitable golden rule.
 
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Apr 11, 2024 at 12:00 PM Post #11 of 44
There are myriads of amplifiers based on the same tubes and they all sound different.
I understand that the size of the nutube was a large limitation of the capacity to render tubes sound.
N3Ultra maybe much better than N8II is at convey that warm color and divert from silicon sound.
But we agree that the amp stage will add its own character to the final stack.
 
Apr 11, 2024 at 12:57 PM Post #12 of 44
I understand that the size of the nutube was a large limitation of the capacity to render tubes sound.
N3Ultra maybe much better than N8II is at convey that warm color and divert from silicon sound.
But we agree that the amp stage will add its own character to the final stack.

Size doesn't really matter IMHO, the circuitry matters. For instance, if you want to add more warmth to a tube amplifier, changing the smaller driver tube normally will create more impact than changing the larger power tube.

Two things that matter:
  • The circuit design especially the way you use NFB affects the tonal characteristic of the Nutube measurements and performance
  • The Nutubes-based DAP or portable amplifiers are hybrid tube amplifiers, meaning the final output stage of these amplification circuits is solid-state, if you are looking for the "tubey" sound like a desktop transformer coupled fully vacuum tube amplifier, you probably need to adjust your expectations.
 
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Apr 11, 2024 at 12:59 PM Post #13 of 44
@Andykong As a big fan of Cayin Products and owning N8,N6ii (All boards except A01) ,RU6,RU7&C9, I have never been more pleased by any other brand in this hobby. There is always a never ending chase for the perfect sound (which only exists in ether :ksc75smile:). If you could make C9ii sound like WA8 or OTL tube amps (Warm) with C9 level of incredible dynamics, you are going to break transportable market big time. I wish you and Cayin all success and hope I can be part of this journey someday when I have the means to do so.
 
Apr 11, 2024 at 1:07 PM Post #14 of 44
super exciting, cannot wait to get my hands on the C9ii
 
Apr 11, 2024 at 2:15 PM Post #15 of 44
If you read the article, you'll notice that the C9 and N8ii shared one common objective: we didn’t design the KORG Nutube to sound like a vacuum tube, it became a means in an audio device that delivers high-end audio performance.

We couldn't make everyone happy, we have to position ourselves to maximize our profit while building up our brand and sharpening up our engineering/technologies, in other words, we must compromise.

The Gen3 Vacuum tube circuit is a big step along this line because when we have TWO tube timber (Classic and Modern) instead of one, we can satisfy a larger group of users, but in a nutshell, when we widen our coverage from making 70% users happy to making 90% users happy, unfortunately, some users will still be unsatisfied with our choice. After all, "we couldn't make everyone happy" is the inevitable golden rule.

Thank you for the reply. I am sorry if I sounded aggressive, I am just very excited.
The read-up was interesting really explains my experiences with the C9.
 

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