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

[Erick Muller]

I would recommend N7 as a good source for C9 and C9ii. We purposively added the Pre-amp output in N7 to fill the gap, making it one of the very few DAPs that can explore the Pre-amp input and Line level input to these portable amplifiers in a compact form factor.

Will the RU7 work well with this new C9ii if I'm using it on LO mode?

 

[Andykong]

@Andykong Will the battery circuit be designed accoring a similar principle to the C9 with its 18650 battery tray? The pictures seem to suggest that ...

Yes, the C9ii power supply is designed around 18650 batteries.

 

[Andykong]

Will the RU7 work well with this new C9ii if I'm using it on LO mode?

In short, yes, you can use RU7 in LO mode as the source for C9 and C9ii, they are functionally compatible.

To further explore the pros and cons of this paring, we need to revisit the Line Out feature of RU7:

The Line out of RU7 is a shared line out, it is inferior to an unamplified dedicated line out. It is a fixed voltage output from the phone amplifier, so they are not significantly different from manually setting the phone output to a specific gain/volume setting. To retain the resolution and dynamic of the RU7 circuitry while controlling the noise and distortion, we can only offer the line out at 1.2V for singled-end and 2.4V for balanced, this is significantly lower than the standard line-level output of our DAPs.

 

[Erick Muller]

In short, yes, you can use RU7 in LO mode as the source for C9 and C9ii, they are functionally compatible.

To further explore the pros and cons of this paring, we need to revisit the Line Out feature of RU7:

The Line out of RU7 is a shared line out, it is inferior to an unamplified dedicated line out. It is a fixed voltage output from the phone amplifier, so they are not significantly different from manually setting the phone output to a specific gain/volume setting. To retain the resolution and dynamic of the RU7 circuitry while controlling the noise and distortion, we can only offer the line out at 1.2V for singled-end and 2.4V for balanced, this is significantly lower than the standard line-level output of our DAPs.

Understood, thank you Andy. So in short, if i paired this amp with the RU7 using LO, I might get less head room because of the lower voltage output.

 

[ssriram2791]

@Andykong Excited for C9ii... can you spill beans on "Anode" selection ? Is this supposed be similar to line in/pre in mode selection we have on current C9 ?

 

[audionewbi]

I hope this one has a warmer tonality option.

 

[Andykong]

Comparing C9ii and C9​

​	C9ii​	C9​
Anode	By adjusting the anode voltage of the Nutube 6P1 vacuum tube, the linearity and harmonic distortion of the audio signal can be manipulated. The size and proportion of various harmonics can undergo significant changes, resulting in different auditory experiences. Options: H (High) or L (Low)	N/A
Timbre	Offer three timbre options, an adaptation of the Gen3 Nutube 6P1 vacuum tube circuit from N30LE. Please refer to the previous explanation HERE. Options: M (Modern tube), C (Classic tube), or SS (Solid-state).	Dual Timbre only T (tube) or SS (Solid-state)
Amplification Mode	The Hyper mode prioritizes audio output as the most important factor, putting all constraints such as heat dissipation and battery life aside. It combines Class A and numerous operation adjustments and delivers the ultimate performance of the C9ii amplification circuit. Options: A (Class A mode), AB (Class AB mode), and Hyper mode.	The Dual Amplifier Operation (DAO) biased the transistors to offer two distinctive amplification modes with the same circuit. Options: A (Class A mode) or AB (Class AB mode)
NFB Mode	Different feedback circuits will significantly alter the dynamic characteristics of the amplification circuit, leading to considerable differences in total harmonic distortion, harmonic distribution, transient intermodulation distortion, and output impedance. In terms of spatial sense, sound cohesion, soundstage, and timbre, different feedback settings provide unique audio characteristics for users to adjust. Options: LFB (large loop feedback) and NFB (large loop feedback deactivated)	N/A
Battery Tray	Two tool-free latches, one on each side.	Secured by two screws, one on each side.
Amplification Circuit	Fully symmetrical discrete headphone amplifier circuit, with a symmetrical differential input stage composed of LSK489 and LSJ689 twin-paired audio JFET transistors.	Non-symmetrical circuit architecture, with a non-symmetrical differential input stage composed of LSK489.
Battery	4x 3400mAh 18650 in series.	4x 3000mAh 18650 in series.

As usual, we provide the technical explanation of our features and circuit implementation, but we'll leave a subjective impression of these features to users and reviewers. We'll demo several Engineering samples at the HK high-end AV show 2024 tomorrow, let's hope our friends and users will share their impressions of C9ii.

PS. Can someone tell me how to adjust the column width when I compile a table in a post?

 

[ssriram2791]

Comparing C9ii and C9​

​	C9ii​	C9​
Anode	By adjusting the anode voltage of the Nutube 6P1 vacuum tube, the linearity and harmonic distortion of the audio signal can be manipulated. The size and proportion of various harmonics can undergo significant changes, resulting in different auditory experiences. Options: H (High) or L (Low)	N/A
Timbre	Offer three timbre options, an adaptation of the Gen3 Nutube 6P1 vacuum tube circuit from N30LE. Please refer to the previous explanation HERE. Options: M (Modern tube), C (Classic tube), or SS (Solid-state).	Dual Timbre only T (tube) or SS (Solid-state)
Amplification Mode	The Hyper mode prioritizes audio output as the most important factor, putting all constraints such as heat dissipation and battery life aside. It combines Class A and numerous operation adjustments and delivers the ultimate performance of the C9ii amplification circuit. Options: A (Class A mode), AB (Class AB mode), and Hyper mode.	The Dual Amplifier Operation (DAO) biased the transistors to offer two distinctive amplification modes with the same circuit. Options: A (Class A mode) or AB (Class AB mode)
NFB Mode	Different feedback circuits will significantly alter the dynamic characteristics of the amplification circuit, leading to considerable differences in total harmonic distortion, harmonic distribution, transient intermodulation distortion, and output impedance. In terms of spatial sense, sound cohesion, soundstage, and timbre, different feedback settings provide unique audio characteristics for users to adjust. Options: LFB (large loop feedback) and NFB (large loop feedback deactivated)	N/A
Battery Tray	Two tool-free latches, one on each side.	Secured by two screws, one on each side.
Amplification Circuit	Fully symmetrical discrete headphone amplifier circuit, with a symmetrical differential input stage composed of LSK489 and LSJ689 twin-paired audio JFET transistors.	Non-symmetrical circuit architecture, with a non-symmetrical differential input stage composed of LSK489.
Battery	4x 3400mAh 18650 in series.	4x 3000mAh 18650 in series.

As usual, we provide the technical explanation of our features and circuit implementation, but we'll leave a subjective impression of these features to users and reviewers. We'll demo several Engineering samples at the HK high-end AV show 2024 tomorrow, let's hope our friends and users will share their impressions of C9ii.

PS. Can someone tell me how to adjust the column width when I compile a table in a post?

Even though you may not agree, this to me is Cayin C10.. We have taken C9 and turned it up to 11.. Too many permutations and combinations...

 

[Erick Muller]

Comparing C9ii and C9​

​	C9ii​	C9​
Anode	By adjusting the anode voltage of the Nutube 6P1 vacuum tube, the linearity and harmonic distortion of the audio signal can be manipulated. The size and proportion of various harmonics can undergo significant changes, resulting in different auditory experiences. Options: H (High) or L (Low)	N/A
Timbre	Offer three timbre options, an adaptation of the Gen3 Nutube 6P1 vacuum tube circuit from N30LE. Please refer to the previous explanation HERE. Options: M (Modern tube), C (Classic tube), or SS (Solid-state).	Dual Timbre only T (tube) or SS (Solid-state)
Amplification Mode	The Hyper mode prioritizes audio output as the most important factor, putting all constraints such as heat dissipation and battery life aside. It combines Class A and numerous operation adjustments and delivers the ultimate performance of the C9ii amplification circuit. Options: A (Class A mode), AB (Class AB mode), and Hyper mode.	The Dual Amplifier Operation (DAO) biased the transistors to offer two distinctive amplification modes with the same circuit. Options: A (Class A mode) or AB (Class AB mode)
NFB Mode	Different feedback circuits will significantly alter the dynamic characteristics of the amplification circuit, leading to considerable differences in total harmonic distortion, harmonic distribution, transient intermodulation distortion, and output impedance. In terms of spatial sense, sound cohesion, soundstage, and timbre, different feedback settings provide unique audio characteristics for users to adjust. Options: LFB (large loop feedback) and NFB (large loop feedback deactivated)	N/A
Battery Tray	Two tool-free latches, one on each side.	Secured by two screws, one on each side.
Amplification Circuit	Fully symmetrical discrete headphone amplifier circuit, with a symmetrical differential input stage composed of LSK489 and LSJ689 twin-paired audio JFET transistors.	Non-symmetrical circuit architecture, with a non-symmetrical differential input stage composed of LSK489.
Battery	4x 3400mAh 18650 in series.	4x 3000mAh 18650 in series.

As usual, we provide the technical explanation of our features and circuit implementation, but we'll leave a subjective impression of these features to users and reviewers. We'll demo several Engineering samples at the HK high-end AV show 2024 tomorrow, let's hope our friends and users will share their impressions of C9ii.

PS. Can someone tell me how to adjust the column width when I compile a table in a post?

I see that it still haves the pre and line mode from the schematic you're sharing Andy. This is good news.

 

[Saberpunch]

Hey @Andykong , I am not too sure if this was already mentioned, but what is the output spec for the Cayin C9ii? Is it the same as the Cayin C9. I’m looking forward in pairing this portable amp with my Cayin N7!

 

[Andykong]

Hey @Andykong , I am not too sure if this was already mentioned, but what is the output spec for the Cayin C9ii? Is it the same as the Cayin C9. I’m looking forward in pairing this portable amp with my Cayin N7!

We'll demonstrate several hand-built engineering samples at the Hong Kong high-end AV show this weekend. By engineering, we are at the last step of our R&D process, we don't publish measurements of our prototypes, you need to wait till we start our mass production process for that.

 

[Andykong]

Even though you may not agree, this to me is Cayin C10.. We have taken C9 and turned it up to 11.. Too many permutations and combinations...

Well, you are entitled to your opinion, ...

Haha, sorry, can't help myself from doing this.

 

[IgeNeLL]

Yes, the C9ii power supply is designed around 18650 batteries.

Do you think about 21700. I think the size is not too big but the performance can be improved.

 

[WDitters]

Do you think about 21700. I think the size is not too big but the performance can be improved.

Errr.... In devices such as DAPs and (trans)portable amps the available space usually is quite precious ... Not sure if switching to 21700 will help. The 18650 cell is only 68% of the volume of the 21700 cell ... That size difference is quite a bit of room to give up.. And that's not counting any potentially additional heat generated by a much denser battery type. I think I would opt for swapping battery trays instead.

The other factor is maximum sustainable discharge current. In that, the 18650 and 21700 do not differ. Both types come with a maximum sustainable discharge current of 30A. Not sure if anything can be gained there in terms of performance

 

[Erick Muller]

Errr.... In devices such as DAPs and (trans)portable amps the available space usually is quite precious ... Not sure if switching to 21700 will help. The 18650 cell is only 68% of the volume of the 21700 cell ... That size difference is quite a bit of room to give up.. And that's not counting any potentially additional heat generated by a much denser battery type. I think I would opt for swapping battery trays instead.

The other factor is maximum sustainable discharge current. In that, the 18650 and 21700 do not differ. Both types come with a maximum sustainable discharge current of 30A. Not sure if anything can be gained there in terms of performance

Yep, just have two or more sets of 4 18650 batteries, and when you run out on one set, you swap to your other set that's already fully charge. rinse and repeat. Of course in this case it would be really important that you don't mix and matched different batteries from different sets.