Cayin C9: Dual Nutube, Fully Balanced Class A/AB Portable HeadAmp

[Andykong]

Dead currious since im not the most knowledgeable about amp topology. If you significantly increase the discharge rate of the battery does the circuit just utilize the higher limit now? Or is there some form of current limit protection built in? Changing battery voltage is probably a missive no-go I would assume, but would you actualy get benefit in hard to drive panars from higher discharge batteries?

Also, there are a number of chemistries that give voltage output in the C9 designed range. Is your SOC calculation chemistry dependent (I would assume it is)?

Correct. The only worry of damage would be if the battery its self was used as a limiter (which would be a piss poor design). My question was if we would even see any benefit.

We are clearly talking past eachother. This is all else i will respond with for this topic. It is standard design practice to include current limiters when working with batteries to prevent overdrawing them. On top of this, tracing will be designed with certain voltage and current limits in mind. My question was simply if the c9 has limiters designed for the production cells that would get in the way of a higher discharge cell.

Theoretically, you can use the 18650 battery as a limiter if you use protected version battery, but since C9 use unprotected version of 18650, we have to develop our own version of current limiter for safety consideration. The current limiter is a fixed ampere design applied to all impedance loading, and when the output current has exceed this value, we will disconnect the amplifier circuit from the power supply subsystem.

The detail parameters are consider internal design detail, we don't have any plan to disclose such detail to public.

 

[Lu88]

Correct, we make a mistake in our description, we'll correct that ASAP.

The 4.4mm sockets (both input and output) of C9 are grounded, but the supplied CS-44C44 short interconnect is not grounded.

Sorry for our mistakes and we apology for all the inconvenience caused.

Thanks for the clarification. The 4.4mm socket on my DAP is also grounded, so I'll try a grounded interconnect.

(I'm waiting for the Eletech Socrates IC 4.4 to 4.4 with GND to be delivered.)

 

[zen87192]

By the looks of things I may have to revert to something like this as a travel bag/portable listening option.
Has the space, not massive, and I can also pack for all IC's, Batteries, Charger, IEM's with the C9 and DAP when going away. Sorry.... going well off thread with talks of bags/luggage.

 

[Whitigir]

I checked with our Engineers, the SE to BAL conversion circuit is designed to work with the input detection mechanism. C9 will detect whether you have inserted 3.5mm or 4.4mm connectors as input and output, and invoke appropriate conversion when needed. The detection involves applying a very low level signal to the Ground contact area (for both input and output 4.4mm socket, that will be the Sleeve of TRRRS). We cannot detect whether there is an active signal in L- or R- because that will involve applying a very low level signal to these two "rings" and this will introduce background noise that might be audible at low output level.

For these reasons, we always assume the input signal is a balanced signal when we plug a 4.4mm connector into the balanced input of C9. We cannot detect the absence of L- and R- signal and therefore cannot support a 3.5mm to 4.4mm adapter cable as C9 input properly.

Thank you very much for your confirmations

 

[Whitigir]

Correct, we make a mistake in our description, we'll correct that ASAP.

The 4.4mm sockets (both input and output) of C9 are grounded, but the supplied CS-44C44 short interconnect is not grounded.

Sorry for our mistakes and we apology for all the inconvenience caused.

I actually do not think the ground on the output 4.4mm is grounded. The input definitely do.

A02 is also grounded on both output

 

[Andykong]

Hi Andy,
would you mind expanding on how the Battery operation regarding Ampage discharge and any internal C9 protections and limiters that are in place work please?

Dead honest, with the operating voltages at play here, I suspect it was pretty easy for them to just size traces and components enough it is a non-issue. 35A discharge is already massive for the 18650 formfactor (given most 18650 cells are ~3.7V nominal and 4.3V max to keep interchangeability a bit higher). If it handes those dont realy worry about it. Its just nice to have explicet confirmation when possible. By the timer higher discharge sources with adequate lifecycles are avaible we will probably be wanting a different amp anyways

Will THIS serve your purpose?

There are always new battery technologies round the corners, we get that every month at the end of 6 o'clock news or gadget magazines. Unfortunately these reports only looks at new technologies at laboratory level. It will take ages for any of these technologies to become feasible for mass production, and take forever before it can be certified to use at consumer level such as flight, hospital, or mass transit system. I remember when I join Cayin back in 2015, fuel cell was a hot topic and it was supposed to be "round the corner". The question is, do you think there will be a battery-tray based fuel-cell portable headphone amplifier when you "wanting a different amp"?

 

[Andykong]

According to the sheets here, the C9 input sensitivity is 6V max for balanced in where the Dx300 is listing @ 7.1V maximum.

There were some user mentioning that the C9 was clipping and distorted previously before Andy and others have agreed that the powerful line out voltage was triggering the distortions

Did iBasso stated the output level of DX300 line out in their specification? Someone said upto 8V, and you have quoted 7.1V maximum.

 

[Whitigir]

Did iBasso stated the output level of DX300 line out in their specification? Someone said upto 8V, and you have quoted 7.1V maximum.

Yes, it is stated in their user manual pdf

 

[twister6]

Thanks for the clarification. The 4.4mm socket on my DAP is also grounded, so I'll try a grounded interconnect.

(I'm waiting for the Eletech Socrates IC 4.4 to 4.4 with GND to be delivered.)

and speaking of that, @Eric Chong just posted a few teasers of Eletech upcoming IC cables and leather storage cases. I think it will be perfect to match some of your man-purses Actually, it is kind of fascinating that their new product was driven by the demand from C9 owners.

 

[Whitigir]

and speaking of that, @Eric Chong just posted a few teasers of Eletech upcoming IC cables and leather storage cases. I think it will be perfect to match some of your man-purses Actually, it is kind of fascinating that their new product was driven by the demand from C9 owners.

Let me guess, the one up top is grounded, which is one single wire running from Sleeve to sleeve (ground) and not a complete (right shield ), because I counted 5 wires. The one below is non grounded

 

[twister6]

Let me guess, the one up top is grounded, which is one single wire running from Sleeve to sleeve (ground) and not a complete (right shield ), because I counted 5 wires. The one below is non grounded

Yes, I think he mentioned before that top one, their flagship Iliad cable, will use 6 conductors and the ground between Pentaconn plugs will be interconnected. Will it make any perceived difference in sound? I don't know, can't tell without having the identical setup with the same IC wires where one is grounded and another one is not.

 

[zen87192]

I'm a bit confused. Should I be buying grounded IC's or ungrounded IC's.
I see both being purchased or recommended.
Thick person (within electronic topology) making this question I'm afraid... sorry.

 

[Andykong]

A bad cables with L+ and R+ shorted would possibly be damaging the Dx300 amp....but that it would also damage the C9....and you wouldn’t be hearing music lol
Common mistakes happened when L- and R- are shorted to ground because the user mistakenly plugged Balanced out into a cables that has single ended end. But this can not happen on Dx300 stock amp as the Dx300 can differentiate and enable SE line out

**I never seen L+ and R+ to be shorted, unless possibly some mistake in DIY cables that wired 2.5mm into 3.5 mm under a wrong polarities** ? That would be some thing very special and unique instances though

I do not think there is any amplifier that has built in protections for shorting out the signals

I did come across a short circuit between R- and GND of 4.4mm connectors back in January. A tour reviewer didn't push in his 4.4mm phone jack into the amplifier completely, so R- ring of the headphone jack get into contacted with the GND sleeve of the 4.4mm socket. the amplifier last for 5 minutes and he can hear distortion after that, and the a complete dark out.

I am still trying to figure out the consequence of "C9 is grounding the negative side of the balanced circuit". Unfortunately my ignorance limited my imagination.

 

[RTodd]

I did come across a short circuit between R- and GND of 4.4mm connectors back in January. A tour reviewer didn't push in his 4.4mm phone jack into the amplifier completely, so R- ring of the headphone jack get into contacted with the GND sleeve of the 4.4mm socket. the amplifier last for 5 minutes and he can hear distortion after that, and the a complete dark out.

I am still trying to figure out the consequence of "C9 is grounding the negative side of the balanced circuit". Unfortunately my ignorance limited my imagination.

I was wondering about that, sounds like it could be the culprit to me.

 

[Shawnb]

I'm a bit confused. Should I be buying grounded IC's or ungrounded IC's.
I see both being purchased or recommended.
Thick person (within electronic topology) making this question I'm afraid... sorry.

Sane confusion here. Not sure what to buy either.