[DaYooper]

I did get one, from Musicteck. I ordered it with the C9 but I changed my mind and got the HA-6A instead., But I kept the A02 and glad for it.

 

[bluestorm1992]

I did get one, from Musicteck. I ordered it with the C9 but I changed my mind and got the HA-6A instead., But I kept the A02 and glad for it.

I am receding an E02 in the afternoon. Curious to compare the LO performance between the two. Have you done any comparison between A02 and other motherboards?

 

[DaYooper]

Not yet.

 

[Whitigir]

Found! Thanks very much , will be happily joining the club soon

 

[Whitigir]

A02 Audio Motherboard, the last piece of puzzle to complete the N6ii platform

Cayin yesterday announced the fifth Audio Motherboard for N6ii. The well-received E01 and E02 Audio Motherboards have reinforced our rational on N6ii: pursue ultimate by focusing on one thing at a time. While a lot of DAPs try to support as many connectors/formats as possible, the E01 and E02 go the other way round by supporting only one headphone output on each Audio Motherboard. The A02 takes another big step forwards by not providing any headphone output at all. In other word, A02 won't drive your headphone or IEM. It offers shared line out and pre out (selectable by pull down menu) on both 3.5mm single-ended and 4.4mm balanced connector. In other word, the A02 transform the N6ii into a high quality analog source for portable headphone amplifiers, active studio monitors, integrated amplifier or power amplifier of home audio system, but you cannot use it for headphone applications directly.


A02 offers two shared Pre/LO connectors (3.5mm and 4.4mm)

A Familiar Digital Audio platform

The A02 Audio Motherboard adopted the same DAC architecture with N8 using two AK4497 in Mono mode and we had used this DAC chipset in the first Audio Motherboard A01 as well. We are very familiar with this high quality DAC chipset in portable application. The sheer resolution and density of the analog output from this chipset is impressive and in our opinion, a perfect choice for the A02 purpose.

The decoding capability is basically the same as A01 Audio Motherboard. It will decode DSD upto DSD256 (1Bit/11.2MHz) and PCM upto 32Bit/384kHz.

Line Out and Pre Out

Cayin N6ii users should be familiar with the concept of Line out already. When we launch E02, the unamplified 4.4mm balanced line out is well discussed and received, a lot of users even acquired 4.4mm to 3.5mm adapter in order to achieve 3.5mm single-ended line out from E02. The good news is, with A02 Audio Motherboard, you can have both 3.5mm single-ended and 4.4mm balanced line out without needing an adapter. Since headphone amplifier is completely absent in this Audio Motherboard, we have the luxury to install 3 line amplifiers (one for 3.5mm single-ended and two for 4.4mm balanced) and optimized for line out purpose, so rest assure these are very high quality line out among portable DAPs. As usual, we offered choices of output levels to Line Out so that users can always achieve best configuration with respect to the gain level of the connected amplifier. Users can specify High, Mid and Low from Line Out setting under Music Setup menu. The corresponding output level is document in the table below.



The other unique feature of A02 is Pre-amplifier output. We believe this is the first ever similar implementation among portable DAPs. Both output connectors on A02 are configurable into Line Out or Pre Out through pull down menu.

So what exactly is pre-amp output? How is it different from Line Out? In simple terms, Line Out is a fixed level output that is unaffected by the volume control. Pre-Amp output, on the other hand, is a variable level output that you can adjust through the volume control. In other word, you should connect the line level output to a variable gain audio device (i.e, with volume control) and connect the pre-amp output to a fixed gain audio device (e.g, power amplifier or power speakers)

In addition to volume control, the output level of these two options might also be varied. The Line output is, in many cases, a buffered output from DAC (and LPF) with little or no gain. Pre-Out varied significantly among different brands or different products line from the same brand. I have seen preamp with maximum output as low as 4V, and I have also seen preamp with maximum output as high as 20+V, and in this case, the maximum output of pre out from A02 is 8.2Vrms (4.4mm balanced) and 4.2Vrms (3.5mm single-ended) respectively. This is a relatively high output level for portable device and it should have enough gain (and flexibility in volume control) to mix and match with different power amplifier in home audio system. On the other hand, with a 4.4mm to dual XLR Balanced adapter, you can use the preamp output from A02 to drive active speakers such as ATC SCM19A (home audio System) or Dynaudio BM5 MK3 (desk-fi system)

To implement these features correctly, the pre-out from A02 has its dedicated line amplifiers (independent from line out). Again, we used 3 line amplifiers (one for 3.5mm single-ended and two for 4.4mm balanced) and they are optimized for pre-out specifically. Last but not least, we use a low noise and low distortion 4-channel resistance ladder electronic volume control from JRC instead of the digital volume of AK4497 in A02. This will ensure the pre-out can deliver stellar dynamic range even at low volume level.



User Selectable LPF

Sine we don’t need to include headphone amplifier circuit in A02, we have room to explore some new options to increase the versatility of the Audio Motherboard. In this particular attempt, we have installed two distinctive set of LPF, the DSD LPF is 3rd order RC Filter and the PCM LPF is 2nd order RC Filter. The DSD LPF is a sharper High frequency filter when compare to the PCM LPF. We call this DSD LPF because it can tame the excessive high frequency noise for DSD material effectively before feeding the DAC output to the analogue circuit.

It is worth noticing that using DSD LPF for DSD material is not an absolute requirement, nor is using PCM LPF for PCM material. After you installed A02 to your N6ii, you can find three LPF settings available from pull-down menu: Auto, DSD and PCM. When you select Auto, the system will select the predefined filter according to the format of current playback. On the other hand, you can select DSD LPF or PCM LPF manually. By controlling the level of high frequently filtering, you can achieve your preferred sound signature. For the record, T01 Audio Motherboard employs 3rd orders LPF and A01, E01, E02 employ 2nd order LPF. So there is no such thing as 3rd order is better than 2nd order, or vice versa. It's a matter of optimization and since we happen to have ample space in this particular Audio Motherboard, we offer both so that you can make your own choice.


PCBA of A02 Audio Motherboard


Functional Framework of A02 Audio Motherboard.

So N6ii with A02 is a DAP without headphone output. This is a bold move even for Cayin, we’ll never be able to do that with regular DAP products, the modular design N6ii is the only platform that allow us to try out innovations like this, nevertheless this is a niche market within the personal audio niche market, we do not expect a lot of N6ii users will need this, but we believe this is a good inclusion in N6ii Audio Motherboard family. When we launch N6ii, we adopted the slogan of “Unlimited Possibilities”, and we think the A02 just opened up a lot of possibilities to N6ii users.

In view of specialized features, the A02 aims at a very niche market and we'll only commit one production batch of 500 units. The suggested retail price of A02 is US$419 and available by mid-October 2020.

PS. Cayin will take a short break from 1-8 October for Chinese National Day and resume duty on 9th October 2020.

PPS. We do not have any Audio Motherboard in our development plan after A02, so unless a very innovative and feasible idea comes up down the road, this is it.

You know Andy ? Why don’t Cayin start working on any R2R and GAN Fets technologies? Those should be “Very Innovative”

 

[Andykong]

You know Andy ? Why don’t Cayin start working on any R2R and GAN Fets technologies? Those should be “Very Innovative”

GAN Fets or even class D amplification is not included in our plan so far. We'll rather wait and see for market response before we jump on board.

We have studied R2R DAC and we like it, but implementation is a nightmare, especially for portable application.

 

[justsomesonyfan]

GAN Fets or even class D amplification is not included in our plan so far. We'll rather wait and see for market response before we jump on board.

We have studied R2R DAC and we like it, but implementation is a nightmare, especially for portable application.

if the implementation can be anything near the r2r2000 level with the cayin package that's a summit giant killer in my eyes.. multibit ones tho, not the new d-s chips

 

[Whitigir]

@Andykong , is there a way to rotate the screen on N6II?

 

[bluestorm1992]

@Andykong , is there a way to rotate the screen on N6II?

You got your N6ii and A02?

 

[Whitigir]

You got your N6ii and A02?

Yeah, it considerably shaves down the weight from the Max. It also offers more filters options, which is great. The Max and the A02 is at least on par, with different tuning. Surprisingly the A02 doesn’t have that recessed vocal and mid as much as other AKM players I have been through.

 

[bluestorm1992]

Yeah, it considerably shaves down the weight from the Max. It also offers more filters options, which is great. The Max and the A02 is at least on par, with different tuning. Surprisingly the A02 doesn’t have that recessed vocal and mid as much as other AKM players I have been through.

Exactly. I think it has really nice synergy with C9. The vocals are just in the right place. Also, some people compared A02 with E02’s line-out and concluded that E02 is in fact too narrow; of course it is a ESS chip.

BTW are you charging the N6ii and C9 at the same time? Looks like the case in the pic.

 

[justsomesonyfan]

Yeah, it considerably shaves down the weight from the Max. It also offers more filters options, which is great. The Max and the A02 is at least on par, with different tuning. Surprisingly the A02 doesn’t have that recessed vocal and mid as much as other AKM players I have been through.

very very interesting, do you have / plan to make a full review on the a02?

 

[Whitigir]

Exactly. I think it has really nice synergy with C9. The vocals are just in the right place. Also, some people compared A02 with E02’s line-out and concluded that E02 is in fact too narrow; of course it is a ESS chip.

BTW are you charging the N6ii and C9 at the same time? Looks like the case in the pic.

Yes, I do charge both at the same time

very very interesting, do you have / plan to make a full review on the a02?

I probably will, but it will take sometime

 

[bluestorm1992]

Yes, I do charge both at the same time

I probably will, but it will take sometime

I remember Andy said in C9’s thread that it is not ideal to charge both of them simultaneously - this may short C9.

 

[Whitigir]

I remember Andy said in C9’s thread that it is not ideal to charge both of them simultaneously - this may short C9.

He said this, So I am only charging it from wall charger and not the same PC with multiple USB. I have been doing this, and don’t see why it would be a problem though. Just as long as both devices is off

1. The Battery module and the C9 audio circuit did not share a common ground, so it is likely that there will be potential different between the two grounds. Therefore it is very important to charge the battery with a separate USB charger. Using the USB from connected audio source equipment (such as computer or media player) to charge up the C9 batteries will trigger the short circuit protection, and might even damage the device and/or connected source equipment.