[twister6]

So what your asking is if the dual stereo channels of the "2ch" AK4490 dac are each hooked to their own amplifier. From what I see on AK4490 pin out, no, they are not, the AK4490 outputs a single set of balanced signals the same way a balanced stereo dac like the "1ch" PCM1792A.

Also I think your terminology is potentially confusing, we should be calling AK4490 a 4ch dac and PCM1792A a 2ch dac.

It's not up to what you or I want to call it, it's how AKM refer to it in a datasheet. AK4490 is 2ch DAC with, each channel having balanced (+/-) outputs, not single ended referenced to a common ground, but rather balanced. So you are processing L/R channels separately, similarly like you would with 2 separate dacs. At least that's my understanding.

 

[T.R.A.N.C.E.]

It's not up to what you or I want to call it, it's how AKM refer to it in a datasheet. AK4490 is 2ch DAC with, each channel having balanced (+/-) outputs, not single ended referenced to a common ground, but rather balanced. So you are processing L/R channels separately, similarly like you would with 2 separate dacs. At least that's my understanding.

 
They literally mean 2 channel though, PCM1792A is also 2ch, it has balanced +/- outputs for each L and R. The AK4490 can process each stereo set (L/R) of channels separately like a dual dac (aka 4 dac channels) which has advantages, but it still outputs a 2ch set of balanced outputs same as the PCM1792A... So it is not like having 2 separate dac outputs.

 

[Andykong]

Thanks for your candour Andy. Indeed the N6 on low gain do drive my HD650 to a very loud volume if required.

Are you implying your opinion that the N6 also lacks the power to make the HD650 sing properly? If so I'm a bit confused, as to me the N6 has maybe 2-3 times more power than I can ever use (I am not interested in permanent hearing damage).


Were any full size or on ear headphones used as reference points for calibration of the N5 in addition to the IEMs you mentioned previously?

Cheers

I believe Philips X1 and HD650 were used as reference during the product development stage of both N5 and N6.

I didn't use HD650 with N6 myself, but I have tried HD540G (600 ohm) and find it enjoyable, but no where near the performance when driver by an appropriate desktop headphone amp.

In terms of power rating, N6 is not significantly more powerful then N5, but the BTL (Dual Mono) design in N6 provides much higher voltage swing at the same power rating, and that's what it count when you are driving high impedance cans.

 

[Andykong]

@Andykong
, regarding N5 design topology:

I'm curious why LO output comes after headphone amplification.  Shouldn't it be after DAC section?

Also, do I read this correctly that audio signal is being processed as dual-DAC balanced output all the way through to HO output?

A while back they mentioned there was issues creating a separate line out in conjunction with balanced topology, so they decided to do what you see in the block diagram, Pono player also uses a shared line out (no coincidence it also has balanced output), although the N5 also has the line out going through the volume controller chip which is probably not as ideal. I would also like to know what the 8th opamp does which isn't shown on the block diagram.

The line out from N6 was directly from DAC output bypassing the volume control, voltage amplification and headphone amplification. N5 started off with the same approached but run into difficulties that can't be resolved promptly, I have explained this issue previously, for those who are interested might refer to the post below:

http://www.head-fi.org/t/771208/cayin-n5-dap-release-imminent-product-information-and-discussion-thread/300#post_11843814

 

[Andykong]

[COLOR=0C0C0C]I think LO must be done this way: DAC -> I/V -> LPF -> LO[/COLOR]

[COLOR=0C0C0C]In the PCB pic there is a 8 op-amps, but in functional framework only 7?[/COLOR]

Yes, only 7 Op-Amps in N5 design.

 

[T.R.A.N.C.E.]

Yes, only 7 Op-Amps in N5 design.

 
 But there is 8 opamps in the pic you released. Was it just a prototype that has been changed since?
 

 

[twister6]

 

It's not up to what you or I want to call it, it's how AKM refer to it in a datasheet. AK4490 is 2ch DAC with, each channel having balanced (+/-) outputs, not single ended referenced to a common ground, but rather balanced. So you are processing L/R channels separately, similarly like you would with 2 separate dacs. At least that's my understanding.

 
They literally mean 2 channel though, PCM1792A is also 2ch, it has balanced +/- outputs for each L and R. The AK4490 can process each stereo set (L/R) of channels separately like a dual dac (aka 4 dac channels) which has advantages, but it still outputs a 2ch set of balanced outputs same as the PCM1792A... So it is not like having 2 separate dac outputs. Correct me if I'm wrong.

 
You are right, I should have been more clear that I was making a "functional" analogy.  I usually tell myself not to go into a technical talk cause it will generate more confusion.  After all, component selection is important but it's all up to a manufacture how they are going to use these building blocks, and especially when it comes to a design of amp section which can make or break the final sound.  Take a look at Aune's recently announced M2 DAP with AK4490 DAC.  As we all know, when that going to become a reality, it will sound nothing like N5

 

[twister6]

 

Yes, only 7 Op-Amps in N5 design.

 
 But there is 8 opamps in the pic you released. Was it just a prototype that has been changed since?
 
 

 
Maybe one opamp used as a buffer...  Just speculating

 

[T.R.A.N.C.E.]

v  ok thanks for the info Andy.

 

[Andykong]

 But there is 8 opamps in the pic you released. Was it just a prototype that has been changed since?

Ah, I see what you refer to now.

There is a date code on each PCB, its marked on the left side of the MCU, check that out and compare the date code and you'll figure out the answer.

Up until early August, the line out of N5 was different from where we are now, it was direct from DAC, to an Op-amp, and then to the 3.5mm line out connector. Since they have changed the design, this Line Out Op-amp is no longer needed.

 

[milesjunkie]

Thanks Andy, appreciate that

 

[sodesuka]

Any sound impression/review yet?

 

[nmatheis]

Might want to check this thread on Lowyat every once in awhile: LINK.
 

Spoiler: Interesting table from that thread comparing N6 and N5.

 

[nmatheis]

@Andykong: Can you elaborate on the 4 Digital Filters in N5 vs. 2 in N6? I'm assuming (perhaps incorrectly) that it's referring to the sharp vs. slow DAC filter. If so, what are the other two filters the N5 has?

 

[T.R.A.N.C.E.]

^ The AK4490 comes with 5 digital filters listed below, Cayin has implemented all of them on N5, should be fun times