Cayin C9ii: Dual Nutube Prtable Headphone Amplifier (Gen5 3x Timbre, Anode, NFB, Pre/Line)

[NYanakiev]

Was looking into buying another N30le, i do have some sellers remorse but this, hmm…

I just bought one

Definitely interested in the C9ii- I never had the original but wasn’t too impressed by its added driving power when used with demanding headphones.

Hopefully the new model is significantly more capable.

 

[WDitters]

Calendar blocked for 1:30 PM CET tomorrow

 

[WDitters]

Youtube link to the launch event. The live stream will be conducted in Chinese, so you may need to enable auto-translation to follow along.

 

[Andykong]

We are almost ready. You can check out the C9ii launch livestream HERE. Please be reminded that the announcement will be conducted in Chinese only, it's a live event and we don't have real-time translation or English subtitles provided in this event.

As usual, I'll provide the key content in English ASAP, and answer questions whenever possible. I hope we have an exciting evening with C9ii.

 

[WDitters]

Fingers crossed. It seems there are some startup issues?

 

[Andykong]

Summary of Gen5 Nutube 6P1 Vacuum Tube Audio Circuit

The Nutube Timbre circuit in the C9ii utilizes a three-stage amplification design, with the core components consisting of a matched pair Nutube 6P1 dual directly-heated triode (DHT) vacuum tube and numerous Toshiba 2SK209 audio grade JFETs as buffer amplifier and buffer driver stage before/after the Nutubes.

The Timbre circuit offers three timbre options:
Modern Sound: The harmonic distortion characteristics and sound signature lean more towards a modern style, with greatly reduced thermal noise and a slightly cleaner tube sound. The original C9 was designed with a similar NFB circuit.
Classic Sound: The distribution of harmonic distortion and the sound signature exhibit a classic vacuum tube amplification circuit, with relatively more thermal noise and a richer vacuum tube presentation. The N8 DAP was designed with a similar NFB circuit.
Solid State: A discrete timbre circuit with four Toshiba 2SK209 JFET transistors in a single-ended Class A source follower circuit. A clear, smooth, and fatigue-free audio output with no harshness.

Cayin introduces a new feature “Anode” to C9ii. The High/Low adjustable anode (plate) voltage further enriches and refines the range of vacuum tube timbre. The working principle is that applying different operating voltages to the vacuum tube's plate alters its operating state, ultimately affecting the sound signature of the timbre circuit.

The “Anode” plate voltage adjustment does not affect the solid-state timbre. Thus, in terms of choice of timbre, the C9ii offers four vacuum tube timbre options and one solid-state timbre, for a total of five variations. In contrast, the original C9 only offers two timbre options.

1. Classic + Anode (H)
2. Classic + Anode (L)
3. Modern + Anode (H)
4. Modern + Anode (L)
5. Solid State sound

 

[Andykong]

Summary of Fully Discrete, Fully Symmetric Differential Headphone Amplifier

Cayin has designed a three-stage amplification circuit to embrace the fully symmetric design into C9ii:

• Stage One: Symmetric JFET Common-source Differential input amplifier.
• Stage Two: Symmetric BJT Common-emitter Push-Pull Differential Voltage Amplifier.
• Stage Three: Symmetric BJT Common-collector Push-Pull Parallel Current

From a user perspective, the C9ii offers a stronger load-driving capability and a more transparent sound presentation when compared to the first-generation C9

A new NFB (Negative Feedback) feature is added to C9ii. This feature applies to the three-stage headphone amplification circuit mentioned above. When NFB is set to OFF, the headphone amplification circuit will be regulated by large-loop cross-stage negative feedback. When NFB is set to the ON position, the headphone amplification circuit will be regulated by local negative feedback

The effect of NFB is fairly noticeable. In our opinion, there is no right or wrong in NFB adjustment, it's a matter of personal preference, and adjustable NFB will allow the user to pick their preference on the go.

 

[audionewbi]

The most important question: MSRP.

 

[Andykong]

The C9ii suggested retail price is US$2399
Availability: September 2024
We are still waiting for the delivery of some components, the first production batch will be somewhere between 18-30 September.

On top of the C9ii, our CEO has also displayed an N6iii DAP prototype briefly (30 seconds), alongside a N6ii DAP (the slightly smaller one) for reference. Yes, the N6iii is almost ready, we'll provide more information later this month.

 

[WDitters]

The C9ii suggested retail price is US$2399
Availability: September 2023
We are still waiting for the delivery of some components, the first production batch will be somewhere between 18-30 September.

Traveling backward in time @Andykong ?

 

[Andykong]

The specification and Functional Diagram of C9ii

 

[Andykong]

Traveling backward in time @Andykong ?

I stand corrected

 

[Andykong]

I have updated the Opening Post on Page 1, and added more photos to Post #3.

I am preparing an explanation of the C9ii Timbre circuit and the newly added Anode function, hopefully complete later today. Will prepare another post to explain the Fully Symmetric Fully Balanced headphone amp. during the weekend.

Feel free to raise any questions, I shall try my best to answer promptly. or schedule to write a detailed explanation in a separate post if needed.

 

[ECKHUAAA]

Traveling backward in time @Andykong ?

That must be the the effect of Negative Feedback lol ....back to the future

 

[kmmbd]

I have updated the Opening Post on Page 1, and added more photos to Post #3.

I am preparing an explanation of the C9ii Timbre circuit and the newly added Anode function, hopefully complete later today. Will prepare another post to explain the Fully Symmetric Fully Balanced headphone amp. during the weekend.

Feel free to raise any questions, I shall try my best to answer promptly. or schedule to write a detailed explanation in a separate post if needed.

The C9ii is perhaps *the* product I am looking forward to getting next year. Having owned the original one for over two years now, and due to recently experiencing the N30LE (which, IMO, is the best sounding DAP out there by a distance), this latest release is going to be a blind buy for sure. My biggest gripe on the OG is the battery bay that can be cumbersome to remove, so great to see quick release mechanism there.

Also, I am surprised that the price is kept similar to the original one, while some manufacturers would be tempted to increase the price beyond the $3K barrier. Kudos to Cayin for keeping things level.

I do have some questions having read the specs and product intro:

1. The Hyper mode seems to have better battery life (10.5 hours) than class-A. Is this a typo or something expected? From the description it felt like battery life should be further reduced than class-A mode but specs tell otherwise.
2. How close is the solid-state circuit compared to N30LE? One noticeable difference I see (with the N30LE and even N8ii) is the lack of a P+ mode. Is it something exclusive to those flagship DAPs or does the C9ii offer a similar option via some toggles (or combinations thereof)?
3. Lastly, how does the amp circuit handle very low impedance loads? E.g. 4 ohm or so. The C9 was not particularly optimized for such low impedance loads, so is there any improvements on that aspect in the C9ii?

Congratulations again on the launch and I look forward to trying one out asap.