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

[Andykong]

All You Need to Know about 18650 Batteries in C9ii

The Beauty of User Replaceable Battery

The removable battery module houses 4 x 18650 lithium batteries. We have redesigned the locking mechanism of the battery module, the original C9 is locked into the main unit with two screws, and you need a not-so-popular T6 screwdriver. We received a lot of user feedback asking for a toolless solution, so we returned to our drawing point and developed the quick-release latch that we used in C9ii and N6iii.

You can charge the 18650 batteries while the battery module is attached to C9ii or after you detach it from the amplifier. The battery module supports standard, PD, and QC3.0 battery charging through a USB-C connector. The battery indicator light will flash while charging and will remain steady once the battery is fully charged.

Users can acquire an extra set of 18650 batteries and replace them conveniently to extend the battery duration when needed. In case the original battery is run down after extensive use, the user can replace the battery conveniently, making sure the C9 can serve a very long time without worrying about the 500 charge cycle of the lithium battery.

The battery module is also available separately and we recommend users purchase an additional set of C9ii battery modules if they want to use the C9ii “continuously” or require longer playback time, you can swap the battery module within seconds, causing a minimum interrupt to your music listening session.

There is a very important catch when regarding battery installation. When installing new 18650 batteries into the C9 battery module, be sure to observe the correct polarity. Incorrect battery installation is considered a human error, and any related damage will not be covered under warranty.

Note: After replacing or removing the batteries, the battery module will enter a protection mode. To reset the protection mode, charge the battery module for at least 10 seconds.

Charging the Batteries

The 18650 is very different from the 3.7V Lithium battery that are commonly find in mobile phone and DAP. Excessive discharge and Overcharge will cause permanent damage to the positive and negative electrodes of the 18650 battery. A fully charged 18650 is around 4.2V and a discharged battery should stay at around 3.0V. When the battery discharges below 2.75V for whatever reason, it goes into sleep mode and the battery is essentially useless.

If you have run into this unfortunate situation, you can revive the battery with chargers that feature a rescue mode (or repair mode). However, I don’t recommend you to do that when the battery is used for C9ii. We strongly advise our users to avoid using batteries that are different in age, capacity, brand, model, or charge level in C9ii. Mixing batteries of varying conditions can cause an imbalance between the +8.4V and -8.4V power supply and degrade the audio performance. In addition, mixed batteries will extend charging time and decrease playback duration between charges.

The Confusion of Fast Charging

C9ii works with three types of USB charging protocol, please make sure your charger conforms to these standards:

• Standard 5V USB charger (0.5A to 2A)
• Qualcomm Quick Charge QC2.0 and 3.0 charger (upto 18W)
• Power Delivery (USB-PD) charger (2.0, 9V 2A)

Unfortunately, the word "quick charge" is frequently misused in mobile device marketing. This is like "Xerox 10 copies of this document". Xerox is a brand, but it is so popular that it become a replacement word for photocopying. Likewise, "Quick Charge" is a USB charging protocol developed and owned by Qualcomm, and because Qualcomm CPUs are so dominant in the mobile phone market, Quick Charge is now frequently used as equivalent to "high-performance USB charging". The fact is, there are many different, incompatible high-performance charging technologies developed by different mobile phone companies. Some of the "high performance" USB chargers that come with your mobile phone will only support quick charge/fast charge/flash charge/speed charge of the same brand. This is a means to protect their product ecology as well as save up the license fee to Qualcomm. Yes, you need to pay Qualcomm or use Qualcomm chipset if you want to support QC2.0 and QC3.0 in the USB charger.

As a thumb of rule, when you use a USB charger provided by your premium mobile phone, claiming that it supports state-of-the-art quick charge technologies, there is a very good chance that they don’t support QC3.0 or PD2.0, if you use these chargers to charge up your C9ii, you will fall back to the basic 5V 2A charging or even less. You have to check the small print on your charger to confirm whether they support QC3.0 or PD2.0 before you can expect “fast charging” with C9ii. In the worst-case scenario, we have run into a situation where the mobile phone charger (from Huawei) refused to charge the C9 completely, so we won’t be surprised if similar things happen to C9ii.

Last but not least, DO NOT use the USB port of your PC or notebook to charge N8ii, this will take forever. The maximum charging capacity of the USB 3.0 port from your PC is 5V 0.9mA. If you are using the USB2.0 USB port, the maximum charging rate drops to 5V 0.5A, which is equivalent to a 2.5W charging capacity, and that will take roughly 26 hours to charge up C9ii when 18W QC3.0 or PD2.0 charger can do that in 3.5 hours.

Note: Some of the frequently quoted 18650 batteries from the C9 thread: Orbtronic, Sony VTC6, Samsung 35E, Panasonic NCR18650B, Sanyo NCR18650GA

 

[Andykong]

The Cayin C9ii product page is up and running now, you can check out the complete product information of C9ii HERE.

I have provided detailed explanations on the following topics

1. Gen5 Nutube 6P1 Vacuum Tube Audio Circuit
2. Fully Discrete, Fully Symmetric Differential Headphone Amplifier in C9ii
3. Our Secret Recipe: Direct Battery Power
4. C9ii Protection Mode
5. All You Need to Know about 18650 Batteries in C9ii

If you read through these topics, you should be fairly familiar with the design, technologies, and limitations of the C9ii. I am not an engineer, I wrote these from the user's perspective, which would make them easier to follow through, hopefully,

I have also pinned these articles at Post #2 Resource and FQA of C9ii.

MusicTeck will display the C9ii flagship portable headphone amplifier and the newly announced N6iii modular DAP (Engineering Sample) at CanJam SoCal this weekend, our other portable products N7 DAP, N3Ultra DAP, and RU7 Dongle DAC will also be displayed. If you are going to attend this Canjam, please schedule some time to check out these new products; your impression and feedback are most appreciated.

 

[ECKHUAAA]

The Cayin C9ii product page is up and running now, you can check out the complete product information of C9ii HERE.

I have provided detailed explanations on the following topics

1. Gen5 Nutube 6P1 Vacuum Tube Audio Circuit
2. Fully Discrete, Fully Symmetric Differential Headphone Amplifier in C9ii
3. Our Secret Recipe: Direct Battery Power
4. C9ii Protection Mode
5. All You Need to Know about 18650 Batteries in C9ii

If you read through these topics, you should be fairly familiar with the design, technologies, and limitations of the C9ii. I am not an engineer, I wrote these from the user's perspective, which would make them easier to follow through, hopefully,

I have also pinned these articles at Post #2 Resource and FQA of C9ii.

MusicTeck will display our C9ii portable headphone amplifier and an engineering sample of N6ii Modular DAP at CanJam SoCal this weekend, if you happened to attend this event, please make sure you schedule some time to check out these new products, and your impression and feedback are most appreciated.

Can we assume that our pre-orders are now shipping out to us ?

 

[Andykong]

Can we assume that our pre-orders are now shipping out to us ?

We have shipped C9 according to dealers order, but unfortunately we have no idea on the pre-order status of different dealers, you have to check if your preorder will be fulfilled in the first shipping batch.

 

[Bengkia369]

Had a listen to Cayin C9II using my Sony WM1ZM2 & Audio Technica ATH-IEX1, sounds really good for female vocals!

 

[Andykong]

A quick comparison between C9 and C9ii, hopefully this can help headfiers to "visualise" C9ii bases on their previous acquaintance with the Gen 1 C9.

 

[zolom]

I know it is a little bit early, but I will be glad to read a Sound Quality comparison between the Cayin C9ii and the Aroma A100TB amplifier (with / without its PS100 PSU).

Thanks.

 

[Bengkia369]

I know it is a little bit early, but I will be glad to read a Sound Quality comparison between the Cayin C9ii and the Aroma A100TB amplifier (with / without its PS100 PSU).

Thanks.

C9II is definitely warmer.
A100TB have more wider soundstage (using Burson V5i as output op-amps and HA8802 as input op-amps all op-amps are attached to Ufeel op-amps buffers) .
For female vocals, I find C9II is the winner, more emotional sound.

 

[zolom]

Thanks for the prompt answer.
My A100TB (with PS100) has the V5i-D on both input and output stages. I chose it a while ago, after reading comparisons vs. the original C9, where it was found superior.
Now, with the new hype of the C9ii, I am curious again.

 

[Bengkia369]

Thanks for the prompt answer.
My A100TB (with PS100) has the V5i-D on both input and output stages. I chose it a while ago, after reading comparisons vs. the original C9, where it was found superior.
Now, with the new hype of the C9ii, I am curious again.

Both A100TB and C9II are good amplifier just sound different.
It all depends on what your preference on the sound signature.
For me, as I listen to mostly female vocals C9II is better sounding to my ears more thicker mids and more focused sound.

 

[MusicTeck]

https://www.head-fi.org/threads/cay...the-fifth-ode-starts-taking-pre-order.974350/ C9II is ready to ship now!
https://shop.musicteck.com/products...adphone-amplifier?_pos=2&_sid=e60f8abc2&_ss=r

 

[ECKHUAAA]

https://www.head-fi.org/threads/cay...the-fifth-ode-starts-taking-pre-order.974350/ C9II is ready to ship now!
https://shop.musicteck.com/products...adphone-amplifier?_pos=2&_sid=e60f8abc2&_ss=r

My C9ii package just arrived from Musicteck, I am letting it Cool down a bit then I will fire it up and share first impressions later today. I will be driving it with N30LE AP and Caldera Open for now as headphones

 

[Deferenz]

My C9ii package just arrived from Musicteck, I am letting it Cool down a bit then I will fire it up and share first impressions later today. I will be driving it with N30LE AP and Caldera Open for now as headphones

Is that a heat sink stand beneath the N30LE?

 

[ECKHUAAA]

Is that a heat sink stand beneath the N30LE?

Yes it is a heatsink I bought from Amazon way back for the N30LE. I don't need it most of the time but I have it to provide an even better heat dissipation in my room

 

[buenahora]

My C9ii package just arrived from Musicteck, I am letting it Cool down a bit then I will fire it up and share first impressions later today. I will be driving it with N30LE AP and Caldera Open for now as headphones

Never thought of using the C9 to drive full sized planar headphones! That's pretty cool - I always thought it was primarily for IEMs only. Would love any additional feedback you can provide.