[Andykong]

Can it be used as Preamp to output toward large stereos Amplifier ?

No, you can't. The C9 only provided two output options: 3.5mm phone out and 4.4mm phone out, there is no line out feature in C9, and the output is too powerful to use as a pseudo Pre out.

 

[Andykong]

Should be easily replaced if it is standard 18650s and the 18650 has the highest energy density of any of the Li cells as for years it was the most commonly used cell so a lot of development went into it. LG, Sanyo and Samsung all make legit 3500 mAh 18650 cells but the rated current output of the Sony used here is higher than any of those so for high current applications like an amplifier so the CDR (discharge rate) was more important than overall capacity.

I can vouch for this seller if you need to purchase cells as I've used them for flashlight and RC apps in times past. https://www.batteryjunction.com/sony-vtc6-18650-3000-flat.html

For the record there are a ton of fakes out there of the higher priced cells so finding a reputable vendor is important.

The trick on the high CDR cells is most have much lower capacity with the highest being about 38A but only 2000mAh. The best LG cell at present is 30A if memory serves but only 2000 mAh. Panasonic hasn't released a cell over 10A (also from memory) instead focusing on high cap as they were the first to break 3000, then 3100, then 3400 mAh

as for button top vs flat top - it sometimes makes a difference depending on the size and shape of the contact pad in the device. if it is designed for a flat top, a button will usually work but those designed for a button may not work with flats as they fail to make a good contact. (Seen that too many times).

Wiljen is an expert in 18650 battery, you can tell by reading his very simple but right to the point posts on the subject.

I am almost ignorant about 18650, so please, give me a hand, you are my life jacket.

 

[svmusa]

Andy - any plans for a desktop version of this? Will be a nice to have an amp with tube and SS timber together without the hassle of a traditional tube setup.

 

[DarginMahkum]

So, I reached out to the German distributor today. The price will be about €2200. They haven't received them yet but hopefully next week or so. I asked about his sound impressions (he already tried a demo unit) and he said "sounds like a more powerful N8", but it wasn't a detailed evaluation.

 

[Whitigir]

So, I reached out to the German distributor today. The price will be about €2200. They haven't received them yet but hopefully next week or so. I asked about his sound impressions (he already tried a demo unit) and he said "sounds like a more powerful N8", but it wasn't a detailed evaluation.

Question of the day
What about an N8 + A more powerful N8 equal ?

 

[DarginMahkum]

Question of the day
What about an N8 + A more powerful N8 equal ?

N89C ?

 

[s6323859]

The C9 use unprotected 18650 batteries.

The C9 can charge itself, you don't need to buy a seperate 18650 battery charger for that purpose. In fact, the removable battery module can continue to serve as a 18650 charger on its own, after detached from C9. You can also purchase additional battery modules from Cayin, that would be very convenient when you want to change the C9 battery, just slip out your first battery module from C9, and then slip in your second battery module immediately, you can continue your listening and then charge your first battery module with a QC3.0 USB-C power bank. Or if you want to AB compare the sound signature of two different set of 18650 batteries, you can perform fast switching when you have two battery modules. In fact, for short term audition with C9 placed on a stable service, you can even left out the two screws that secure the battery module to C9 chassis TEMPORARILY.

Hi @Andykong where can buy battery module?

 

[xand]

I am torn :/ did I make the right choice ?

The way I like to determine the peak power a headphone requires, is to take the maximum impedance across 20-20k, and the lowest sensitivity across 20-20k, and put that into a calculator with an expected output of 115 dB SPL:

calculators e.g.
http://www.digizoid.com/headphones-power.html
https://www.headphonesty.com/headphone-power-calculator/

Using numbers for the HD 800 from https://reference-audio-analyzer.pro/en/report/hp/sennheiser-hd-800.php#rw2

The max impedance is a little difficult to determine, but it looks like maybe 610 ohms. Minimum sensitivity seems to be approx. 96 dB SPL/V.

These are the results:

I don't know what the C9 is rated at (or produces), at 610ohms, but if it does 320mW at 300ohms as rated, perhaps it'll do about half at 610ohms, which might be enough

 

[Andykong]

Looks like you just found a hole in the market.

Then, is it direct DAC output? I wonder the case with SP2000 that you select the output voltage - is it amped or DAC controlled.

Yes, we just spotted a hole, but .... sustainable?

The interesting thing with C9 is that you can AB compare the line out and phone out of SP2000 and pick the combination that you preferred. If you like the sound signature of SP2000 a lot, then the PRE-amp input mode probably will have a higher chance because the final sound signature will leans toward SP2000 in this mode. Alternatively, C9 will play a slightly more dominating role when you use Line input mode.

 

[Andykong]

The DMP Z1 is only 1/4 of the Cayin C9. It is 16Ohms, the DMP is 1500mW where C9 is 4100mW

I think that the DMP Z1 is 2x1500mw at 16 Ohms.. so 3000mw at 16Ohms to compare to the 4100mw at 16 Ohms of the C9..

My goodness, this is a very innovative way to interpret our specification. I have never come across any stereo amplifier manufacturer will quoted their power rating as TOTAL power of two channels in their specification table. I have seen that happens with PMPO (Peak music power output, or something like that) or rated output level (in Vrms). But I accept I can be wrong, so if you have seen something like that previously, please share with us, so I can learn to do a better job when I compile specification table.

By the way, on the C9 product page that you quoted previously, it stated clearly, on key vision page, that C9 will output 2600mW per channel @ 32 ohm. Isn't that just logical that the output at 16 ohm loading is 4100mW per channel?

 

[xand]

Haha love the snark.

 

[DaYooper]

Still haven't seen any expected time frame when I'll be able to put all the watts on my head though.

 

[xand]

Still haven't seen any expected time frame when I'll be able to put all the watts on my head though.

If it helps - my order left China yesterday (to my dealer), expected arrival at dealer is next Friday.

I'm in Singapore.

 

[Andykong]

It seems the C9 is with less than 10V output, around 2x1W for 42 Ohms (no idea if it's in both A or AB class).
I am afraid the C9 should be a bit under powered for some headphones (like HEDD's one at least to help to get some real kicks in low and ultra low frequencies and stay clear and deep without being muddy).

The Centrance M8V2 can deliver in class A more or less 11V and 2x1.4W for 42 Ohms (20V peek power)
The iFi diablo can deliver probably more than 12V and 2x1.8W for 42 ohms (Class AB probably ?)
Even the reference in transportable DAC Amps which is the DMP Z1 is 2x1.5W 16Ohms with good capacitors.. which can produce more or less 2x1.15W for 42Ohms (?).

I was expecting the C9 in a higher power class, like recent iFi's portable items.

Those figures are calculated with what I can read from the specs on their website for the M8V2, I translate it to 2x1.4W with 11V at 42 ohms ? I am using the hot side with XLR4 connection.
The cold side with the 2.5mm balanced plug is claimed to be something only half of the amps activated of what are used for the hot side (XLR4).
The cold side is intended to be used with sensitive IEM or for much longer battery life (15h with stamina activated too).

As it is coherent with my A/B comparison with my A&K Kann Alpha which is far to give the volume and clear and deep impacts as the Centrance M8V2 can produce with my HEDDphones, I think I must not be very far from my approximate calculations.

And for the C9, it seems to be clearly indicated on their website to be at max 2.6W for 32ohms, so I calculated it should be less than 2x1W at 42ohms with 9.2V


But I accept I can be wrong in those figures.

I am not interested to compare rated power output at micro level. In my experience, the different between 10V and 11V or 12V output is insignificant unless other factors such as output impedance, current capability, responsiveness of power supply, ... etc etc are all equal. Some of these parameters are not described from published information, let alone quantifiable and compare as if they are linear variables.

To further illustrate my point, I'll prefer a 10V high current headphone amplifier over 15V moderated current headphone amplifier if I were to focus on low impedance headphones. Different headphone designs have different driving and handling requirements. Take a 50 Ohm double-sided magnetic arrays planar driver and compare it to 50 Ohm dynamic driver, the planar will consume more current by design, and you need a very responsive power supply to control the movement of the dynamic driver accurately.

For the record, the rated output of C9 are the same in Class A and Class AB. We don't lower the output at Class A because our power supply circuit can sustain the output in regardless of Class A or Class AB. The downside is, the inefficient nature of Class A will drain more power when the output remain the same as Class AB. Take a closer look at the battery duration table in our specification if this is important to you.

Last but not least, your calculation/estimation are questionable. As you have pointed out, 2.6W for 32ohms is roughly 9.2V, but 1W for 42ohm is nowhere near 9.2V, that's only 6.48V, something is missing in your calculation.

 

[Andykong]

Thanks for the answers, a little late as I already bought 32x cells of 18650 LOL!!! I am glad it was unprotected. Btw, your recommendations of 300ohms or below headphones for the C9 has just vastly limited the applications for the C9. A lot of people don’t just search any further really. For the HD800s, 300mW@300ohms is enough. Or should I wait for the successor of C9 ? :/

Now I am a little more discouraged to get a C9 at this price, since 300ohms is not recommended (from @Andykong), and BX2 is a lot more powerful, also a DMP used can be found for less than 6K. If you get C9, a DAP and interconnect, it is already 4-5K

I don't know exactly with HD800 and even less with C9, but as far I could see with google, the HD800 is 300Ohms with 102db sensitivity .. the Cayin C9 seems to provide much more power than what the HD800 will be able to bear at 300Ohms.

For the HD800 theoretically the max power should be less 70mw à 300Ohms ... so it looks like the C9 can produce far more power (double ?) than what the HD800 needs.
With my HEDDphone, it is a totally different story with 87Db sensitivity .. Required power is monstrous compared the HD800, the C9 is just falling too short for such low sentivity.

Suddenly HD800 is all over the thread, I'll try to response them in one post.

Did I vastly limited the applications for the C9? A lot of people don’t just search any further? I don't really think so, but if this really happened, I'll continue without hesitation. To be honest, I have shared similar thoughts previously (e.g. HERE), I am pretty consistent in steering people away from using HD800 for portable.

To me, using HD800 with battery powered portable amplifier is workable, some portable amp are better then others for this scenario, but please accept the reality that there are limitation you can't solve by more money. If you only listen to "simple"music, with one of two instrument that does not required a lot of dynamic (bot macro or micro),

First of all, those who try to work out the power requirement of HD800 based on electrical engineering principles and specification, I can tell that you know nothing about HD800, or the real game of headphone/amplifier synergy. The reality is, the formula only tell you how much power you need to make is sound loud, but that is not our requirements, right? We want to hear it sing, not to hear how loud it can go.

The biggest problem with battery powered headphone amplifier and HD800 (or 300ohm headphones in general) is insufficient voltage swing. The impedance ranges of HD800 swing between 340 and 650 ohms (HERE), to handle this kind of impedance swing, you amplifier must have very respectable voltage swing. So what kind of voltage swing can you achieve if your amplifier is powered by one 3.7V lithium battery? Sure you incorporate DC to DC regulation circuit to boost the voltage to 10V, 20V, 30V, but experience amplifier builders will tells you that there are procs and cons in using booster circuit, especially when you are going for 20x or 30x voltage gain. The biggest question is, can the booster circuit response fast enough? will it compromise the transient of the playback? In desktop implementation, we can install arrays of capacitors as buffer to support short-term power requirement, the capacitors are not expensive, nor are they difficult to implement, but they need space to start with, something that portable headphone amplifier are lacking.

To certain extend, the power supply of C9 starts at a much better off situation. The four 18650 lithium batteries are connected as a ±8.4V (i.e., 16.8V) battery power supply, this is significantly higher than the commonly used 3.7V USB rechargeable lithium battery. We don't incorporate any DC to DC regulation circuit in our power line, making sure the power supply is direct, extremely fast responding and noise-free.

Yes, we are better than many portable alternatives, but still, when compare to ±24V power supply with a dozen of 20000 uF electrolytic capacitors (just make up some numbers for comparison purpose, please don't take it specifically), C9 is in a very disadvantage position.

There are other factors that makes HD800 or HD800S difficult on portable environment than other 250 ohms or 300ohms headphones, for example, its unique sound signature, huge soundstage, and music genre that are frequently associated with them, ... just to name a few. These I don't want to turn this thread into a HD800 mix and match thread, so I'll stop here. I hope I have make my point: the problem is not whether C9 has enough output power to drive HD800 to 96dB, its the voltage swing that matters, and low-voltage battery powered amplifier has a congenital defect on this issue.