Head-Fi.org › Forums › Equipment Forums › Portable Source Gear › DAP-off: Astell&Kern AK240, HiFiMAN HM-901, Sony ZX-1, FiiO X5 + Chord Hugo & Calyx M from June.
New Posts  All Forums:Forum Nav:

DAP-off: Astell&Kern AK240, HiFiMAN HM-901, Sony ZX-1, FiiO X5 + Chord Hugo & Calyx M from June. - Page 21

post #301 of 932
Quote:
Originally Posted by T.R.A.N.C.E. View Post
 

 

The top left of the picture is the ZX1's custom digital amplifier chip presumably made and designed by Sony, while other daps use an off the shelf dac chip. The significance is that Sony's chip works like no other dac, being a digital amplifier rather than a digital to analogue converter. Those 4 capacitors in the picture work with the digital amplifier in a phase locked loop charge pump configuration, another design unique to the ZX1, not found on other daps. Not saying its a better design, but it certainly is a very modern and interesting design. The design is only in its infancy being the first time something like this has ever been implemented in a dap, I really look forward to Sony innovating further on this design in future daps and lessening its short comings.

I don't understand.  Why would you amplify a discrete signal which serves no purpose in driving?  Digital is for information only, not a signal for purpose to drive mechanical function(headphones) like any amps.  

 

Well, modern DAPs do not use electrolytics in the path except some audiophile DAPs such as Ibasso and etc.  I think the Sony's uniqueness is custom chip, but has been don with Apple, which hasn't turned into audiophile grade DAPs.  The custom chip alone doesn't have any merit. We know as high-end uses parts from shelf DACs such ass the ESS9018, and etc..  The AK uses off the shelf and it's very successful. As for the Electrolytics, Id like more details on that. You have any links discussing the design?  

 

Just because they use PLL charge pump doesn't mean it provides more power as ZX1 is speced low power than others in it's league.  What you measure is what you get, charge pump doesn't magically increase the power.  Where is PLL being used?  Is it for the clock?  It's purpose is to keep deviations of timing(or phase).  Charge pump is part of PLL, it's keeps the timing.  If this is the case, charge pump has nothing to do with power delivery.


Edited by SilverEars - 5/28/14 at 4:18am
post #302 of 932

Essentially ad speak for how a dac that feeds a class-d amplifier works.  If someone pasted the how a dac that feeds a class-a amp works as marketing people would be just as impressed.  When you dumb it down... less so.  My point for the photos was to illustrate that despite it's size, that space is for the most part not being used for pcb real estate much like the Apple offerings.

post #303 of 932

ZX1 uses a class D digital amp chip, which takes a digital signal and using PWM amplifies it, the PLL is the clock, the Charge Pump converts the signal into frequency output via voltage oscillator.

post #304 of 932
..

Edited by SilverEars - 5/28/14 at 6:03am
post #305 of 932
Quote:
Originally Posted by T.R.A.N.C.E. View Post
 

ZX1 uses a class D digital amp chip, which takes a digital signal and using PWM amplifies it, the PLL is the clock, the Charge Pump converts the signal into frequency output via voltage oscillator.

Just looked up Class D amp.  It takes in analog, modulates it, and stretches the modulated signal and outputs the analog after filtering. I guess it's called Digital amp because the analog gets modulated to PW.  It has higher power efficiency that's all.  The problem is if there happens to be a timing glitch..


Edited by SilverEars - 5/28/14 at 6:02am
post #306 of 932
Quote:
Originally Posted by Solude View Post
 

Quote:

Originally Posted by 62ohm View Post
 

Does anyone have the specs for the ZX-1? What DAC chip(s) is uses and its power output? I couldn't seem to find it. 

 

Sony like Apple doesn't have to use off the shelf parts.  They use these:

 

 

And yes like Apple most of the space is screen and battery.

 

Quote:
Originally Posted by shotgunshane View Post


It doesn't use a dac chip like most daps. Here is a post about its class D type setup: http://www.head-fi.org/t/680853/sony-nwz-zx1-35th-walkman-anniversary-model/285#post_9842562

 

This clears out any interest I had in the Sony :D

post #307 of 932
Quote:
Originally Posted by SilverEars View Post
 

Just looked up Class D amp.  It takes in analog, modulates it, and stretches the modulated signal and outputs the analog after filtering. I guess it's called Digital amp because the analog gets modulated to PW.  It has higher power efficiency that's all.  The problem is if there happens to be a timing glitch..

 

Class D can also take digital signals and convert to PWM, there is no analog input signal in the ZX1,  just digital.

post #308 of 932
Quote:
Originally Posted by T.R.A.N.C.E. View Post  The top left of the picture is the ZX1's custom digital amplifier chip presumably made and designed by Sony, while other daps use an off the shelf dac chip. The significance is that Sony's chip works like no other dac, being a digital amplifier rather than a digital to analogue converter. Those 4 capacitors in the picture work with the digital amplifier in a phase locked loop charge pump configuration, another design unique to the ZX1, not found on other daps. Not saying its a better design, but it certainly is a very modern and interesting design. The design is only in its infancy being the first time something like this has ever been implemented in a dap, I really look forward to Sony innovating further on this design in future daps and lessening its short comings.

 

May I ask where you got this information from? The language is somewhat misleading --- that is to say, PWM principles are very similar to those of a charge pump, but to my understanding, not in the way you're describing it. Either that, or I don't understand your wording.

 

First, the caps shown (Sanyo OS-CON) actually are linked with the inductor behind them as the analog LC low-pass filter. This is the most critical part for the subjective sound of the whole system because it filters away switching noise caused by the MCU IC, and needs to be low noise enough for a high-quality audio signal. That's why Sony chose the OS-CON for the analog section.

 

With regard to the PLL, while I'm no electronic engineer, the PLL is synchronized in step with the clock oscillator (which acts as a transport clock for the digital data), which locks the PWM timer (aka the Sony MCU IC) in phase to pulse modulate a high quality voltage reference (e.g. 3.3V), regulated by LDO linear regulators. To my understanding, the "charge pump" that modulates this specific generated voltage is contained within the surface-mount POSCAP capacitors (which is more suited for high-frequency switching applications than the big round OS-CON caps, and can't really be seen in the pictures shown).

 

S-Master HX works in a "full-bridge" manner, meaning it uses differential input for both L and R channels, so it processes half the signal with negative voltage and the other half with positive voltage and the result is summed. [EDIT: Yes, this means the ZX1 can somehow be modded for balanced output] Volume control is determined by directly altering the analog voltage output. Assuming a perfectly stable voltage reference, this means zero loss of dynamic range at any volume. These are the two diagrams that are most telling regarding the design of S-Master HX on the F880 series and the ZX1 are these two:

 

 

 

The MCU IC in the pictures is central to the performance of the entire system because it determines and controls the switching frequency, as well as the stepping of each pulse. The finer the stepping, the greater the resolution, and the more precise the voltage reference, the greater the resolution. Sony seems to only be able to get S-Master HX to perform to 16-bit precision (which is darn good by PWM DAC standards; if you used an Arduino, chances are you'd get 8-bit resolution, or if you're lucky 10 to 12-bits).

 

The bottom line is, S-Master HX is cool, but it has a lot of technical challenges ahead of it. I find that my F886 is lacking in resolution, and the ZX1 similarly so. Sound output on the ZX1 is refined, however, pointing to the high quality power regulation (also why Sony was able to eliminate DC blocking caps at the output, as each differential channel is ground-referenced and centered) and good LPF design that Sony installed.


Edited by tomscy2000 - 5/28/14 at 9:31am
post #309 of 932

^ Your completely correct in your whole analysis, I had mixed up os-con with poscon before. You have outlined the ZX1 design very well! I do hope Sony continues development and engineering on the S-Master chip, the speed of the sound is unbeatable, although it does lack resolution and power, if those things could be improved Sony would be on to something big.


Edited by T.R.A.N.C.E. - 5/28/14 at 10:57pm
post #310 of 932

So, do any of these have a noticably easier to read in sunlight screen?  I use my DAP outside during breaks at work, and some are almost impossible to read in sunlight....

 

thanks for any suggestions

post #311 of 932
Thread Starter 
Quote:
Originally Posted by fzman View Post
 

So, do any of these have a noticably easier to read in sunlight screen?  I use my DAP outside during breaks at work, and some are almost impossible to read in sunlight....

 

thanks for any suggestions

 

 ?:D

post #312 of 932
Very Good:cool:
post #313 of 932
Looking to buy a new portable source for CIEM,s only. Is it with the trouble of the Hugo as needing a transport . I Have a iPhone 5 64 gig to,use. Now if I buy a ak240 I am done . Is the Hugo that much better with CIEMS. I could see if it would be used with cans as they would be more reviling .
Any ideas ?
Al
post #314 of 932
Quote:
Originally Posted by ALRAINBOW View Post

Looking to buy a new portable source for CIEM,s only. Is it with the trouble of the Hugo as needing a transport . I Have a iPhone 5 64 gig to,use. Now if I buy a ak240 I am done . Is the Hugo that much better with CIEMS. I could see if it would be used with cans as they would be more reviling .
Any ideas ?
Al
To me, for SQ purely, Hugo>901>AK240. As a whole portable package, AK240 will be the best, but I find it much too expensive for the SQ. Whereas Hugo is not. All IMO.
post #315 of 932
Thanks for the view it helps. As I would like the ak240 for its simplicity but as SQ is tops I have to do the Hugo .
I have a Hugo to listen to tomorrow in NYC. I am taking my HDP r10 as transport and a comparison for sound I have low and hirez and dsd as well . I will bring the jh13 fp and the Roxanne's so I have both ultra details and ultra dynamics to listen for . So I am ready
Al
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Portable Source Gear
Head-Fi.org › Forums › Equipment Forums › Portable Source Gear › DAP-off: Astell&Kern AK240, HiFiMAN HM-901, Sony ZX-1, FiiO X5 + Chord Hugo & Calyx M from June.