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I Basso HDP R 10 is IBasso DX 100 Japan Version impression and appreciation thread - Page 4

post #46 of 1326

hey guys, my guess is they are using a DC->DC convertor to get a bipolar output from the 4.2 battery, as such there is very little difference in the battery. a 4.2v 4800mAh is equal to a 8.4v 2400mAh, then some losses for the DC convertor and there is very little difference. the batteries will be practically the same size so it wont be bigger.

 

the opa627 and buf634 would not survive on 4.2v/2 (+/-2.1v) so there is a charge pump or DC-DC convertor there somewhere. truth be told even +/-4.2v is marginal; particularly as all of these battery voltages are nominal voltages, so they will be higher fully charged and considerably lower at the end of charge.


Edited by qusp - 8/22/12 at 8:54pm
post #47 of 1326
Qusp, that is brilliant info. I was trying to work out how they would use the same h/w yet with different voltages. I'd guess the DC<-> DC is tiny enough to fit in there without much changes required to the DX100 board?
post #48 of 1326

yup, wouldnt take up much space, it may even save space overall.

 

more info if desired

 

gratuitous detail (Click to show)

Given the published specs of the dx100, (which are a little vague) i'd say they are already using a similar circuit in that. the dac chip itself only needs multiple +1.2 and +3.3v voltages, probably similar for the clock, they are likely using a 3.3v clock generator. the only thing that will need more in either unit is the I/V convertor and amp section, perhaps the display may use +5v. the ESS because of only having positive supply voltages, means that its balanced output swings around a DC offset of 3.3v/2 (1.65vdc) rather than 0v. This can be cancelled in a number of ways in the output stages, but to avoid output caps they need a negative supply.

 

What it does mean however, is that the Japanese version will be using a virtual ground rather than a split battery with a real center tap like i'm assuming they use in the dx100. What this means is that the impedance to ground and current handling of the ground/return path for the headphones will be better/cleaner in the dx100, as its only limited to the current capability and impedance of the battery/ground plane. The virtual ground impedance and return current capability of the Japanese version, will be set by whatever DC convertor/device and caps they use. the power to source current is limited by and equal to the ability to sink it, ground is at least as important as the signal connection; myself I see it as more important.

 

as such I would take the dx100 over the Japanese version, there will be other trade-offs there too. having a split supply and real center tap means that they need to have some way of balancing the cells during charging, you know, so they dont go all explody from over or under charge on the negative rail. the Neg rail will have a lower power draw than the positive rail, as the dac, clock,  digital circuits and half the output stages are all running on the positive rail, while only the negative going swing of output stage is using the negative rail. This means that the cells negative of center will not drain as quickly as those on the positive side.

 

with all that sorted its preferable to have a split supply, but it does present some obstacles to overcome and perhaps added expense, so the Japanese version may not present an upgrade at all, rather a compromise.

 


Edited by qusp - 8/23/12 at 1:03am
post #49 of 1326

sorry for the info overload, i'm going to put it in a click to see window


Edited by qusp - 8/23/12 at 1:03am
post #50 of 1326
rolleyes.gif
Quote:
Originally Posted by qusp View Post

sorry for the info overload, i'm going to put it in a click to see window
Thank you....you are the man....cool.gif
post #51 of 1326

all completely on topic and I would think even moreso, given there is a direct comparison and people may want to have a basis for decision between the 2, but I realize not everyone wants to know what goes on inside their boxes … tending to choose moreso on the second hand lyrical musings of a third party


Edited by qusp - 8/23/12 at 2:24am
post #52 of 1326
Quote:
Originally Posted by qusp View Post

all completely on topic and I would think even moreso, given there is a direct comparison and people may want to have a basis for decision between the 2, but I realize not everyone wants to know what goes on inside their boxes … tending to choose moreso on the second hand lyrical musings of a third party


I've already ripped opened my DX100 & put pix up on the DX100 thread a few months back :-

http://www.head-fi.org/t/592076/ibasso-dx100-true-24-bit-for-bit-reviews-impressions-apps-imgs-video-pg-1-in-stock/5430#post_8342134

 

I've sorta lost my interest in the HDP-R10 when @takoyaki mentioned that it doesn't support DSD natively. Reading more of the Japanese articles, it turns out to be true that it just downsamples in real time :-

http://www.head-fi.org/t/592076/ibasso-dx100-true-24-bit-for-bit-reviews-impressions-apps-imgs-video-pg-1-in-stock/5430#post_8342134

post #53 of 1326

Yup, I've lost interest too. However, I'm still interested in acquiring one of the accessories that has been made for the HDP-R10, namely the docking station. Should be compatible with the DX100 I hope, or because of the different battery, in fact not?!

post #54 of 1326

qusp

 

i love technical :)

 

thanks for that

 

DC <-> DC conversion is very inefficent even today. I can see AC to DC but to bump the voltage up from the 4.2vDC. That will not be a cheap "loss".

post #55 of 1326
Quote:
Originally Posted by the wizard of oz View Post

Yup, I've lost interest too. However, I'm still interested in acquiring one of the accessories that has been made for the HDP-R10, namely the docking station. Should be compatible with the DX100 I hope, or because of the different battery, in fact not?!

 

Do note that the monoblock is not a docking station but only solid stand cum cable manager. That's all to it. It cannot charge the DX100 and there are no connectors on it.

post #56 of 1326

You mean there's not even a way to use the default charger plug as a discrete charging pin within that dock? Just one movement and charge?! One has to hold the DX100/HDP-R10 in one hand and connect with the other hand said plug?!
Not much to that aluminium mono-block then :( ...

post #57 of 1326
Quote:
Originally Posted by figgie View Post

qusp

 

i love technical :)

 

thanks for that

 

DC <-> DC conversion is very inefficent even today. I can see AC to DC but to bump the voltage up from the 4.2vDC. That will not be a cheap "loss".


No worries.

 

indeed, i'll take (and did so) an actual center tap any day, despite the charging complications. actually after looking at the pics that AnakChan posted, it appears they are using a charge pump or DC->DC convertor to generate the negative rail in the DX100 as well, at least I hope so, if they are charging the cells in parallel, but using them as a center tapped/series battery then there will be serious and possibly dangerous cell balancing issues.

post #58 of 1326

I got mine today.

 

R10 with silicon case

R10's GUI

 

Playing DSF file(DSD)

post #59 of 1326
Experiment to charge R10 with USB battery...

post #60 of 1326

As per DX100 thread. Please do keep up with your impressions. By the way, is the back rubberised? i.e. non scratch material?

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