aleXmod - true audiophile tweak of cowon i-audio X5 DAP
Sep 15, 2009 at 9:00 AM Thread Starter Post #1 of 60

Alex_Nsk

Member of the Trade: aleXmod
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Hi for every music lovers!
Some times ago I look at the market of potrable audio and unfortunatelly just can't found any DAP which suit my taste in quality and perfomance. So I plan to make a true audiophile DAP with increadible sound quality!
As a base I choose a portable enoughth cowon X5L DAP - as a hardwire it suit all my needs, and when rockboxed it could be even better (almost any losless formats, cue, etc). The sad is it's own codec sound quality...
At first I eject the HARD from my DAP, and change it to the PRETEC 32Gb CF memory (aka X5 flashmode).
Then I research and made an upgrade plate whith micro DAC/headphone amp combo, which can be installed inside the X5L instead of it's second battery and connect it to the X5 processor via I2S bus.
The plate consist of two blocks: the first is the DC_DC converters based on TI chips which converts th 3.7v of LI-battery into the +/-5v bipolar voltage; the second is the DAC/headphone amp.
For DAC chip I choose almost top of line TI delta-sigma converter - PCM1798 (could be changed to the top TI chip - PCM1794 if any want). This is a single chip stereo 127dB SN DAC whith built in digital filter. As I/U converter stages I suggest to use some great in sound quality dual operational amplifiers in SOIC (LM4562, AD8620, THS4032, LT1364, LM6172 etc)
Some could choose from this list the only one which suit them at 200% in terms of sound quality..
As HP driver I use the TI TPA6120/THS6012 chip. Dynamic, ultrafast, great in sound quality!
Of course there are a good passive elements as well - Sanyo OS-Con G capacitors in digital PSU, The Black Gate NX/Nichicon MUSE in BIAS of DAC, BLACK GATE St/Sanyo WG/Chemicon KJZ in analog PSU.
The power of HP driver is big enought to drive the 300 Ohm senn HD580/600 (it gives aprr. 48mW@300ohm & 440mW@32Ohm)
And the sound quality of digital music become just as good as it can!
dt880smile.png


Right now there is 2 workin examples of aleXmod.
Else 3 pcs is in progress till the end of september.
Stay tuned if you are interestin' !
P.S. Below is the link to the russian thread about my way (in russian of course) and some pictures...



 
Sep 15, 2009 at 12:30 PM Post #4 of 60
There is intrisict problem with bass roll-off because of blocking electrolityc CAPs which staying in headphone and line-out jacks. As is X5 isn't goog sounding DAP for me.
However with my mode it's sound quality reaches the sound quality of top hi-fi home CDP's and above it! Just nor any ipod-imod-sansas etc come around!
I can made it for everyone interested. Total upgrade of your own flashmodded X5L at the price appr $250-350 depending on parts used(for example the Black Gate NX Caps isn't a cheep toy and rare by the way)
 
Sep 15, 2009 at 2:24 PM Post #5 of 60
Would that include the X5? I am getting interested, but would rather talk it out quite a bit first. I am very sceptical of the word Sound Quality here. It means too many things to too many people and has led me to disappointment many times. Your mod, however, looks great since the X5 needed something to enter audiophile territory.
 
Sep 16, 2009 at 12:45 AM Post #9 of 60
interesting, but this is not the correct venue for an ad
 
Sep 16, 2009 at 4:55 AM Post #11 of 60
Quote:

Originally Posted by Alex_Nsk /img/forum/go_quote.gif
So which one is correct? DIY? If so please move me into the DIY Discussions forum...


if it were DIY then yes; but you are clearly selling a product. To advertise a product on this forum (especially so blatantly) you must first apply to become a member of the trade (MOT) and then pay for a sponsored thread in which to flog your wares. if you werent selling this, but simply sharing it with the community, then there would be no problem and the DIY forum would be perfectly fine, but as you are not doing that, you are in breach of the rules. it is not fair to the paying sponsors that you advertise for free.

nice mod though and once you sort it all out, then i'm sure you'll do fine
 
Sep 16, 2009 at 6:20 AM Post #12 of 60
I'm sorry if unfortunatelly break the rules, im just junior here )
This project started as a DIY hobby, i just want to made and complete the best soundin DA player ever (when I started at april 2009 neither AMP3 nor HFM wasn't presented on the market) BTW to keep project in budget I made some quantity of upgrade printed circuits to suggest it to everyone interested (for minor payment of cause).
But til' 1st july (the aleXmod's birthday) i have seen that many audiophiles want to make the mod, but just cann't because it isn't so easy to deal with smd parts & chips. So I plan to suggest the aleXmod as complete thing for them who want, and don't want to deal with DIY work. For another ones I can sent the plates, the kits with smd parts and so on.
IT ISN'T A TRADIN, IT'S A KIND OF IMOD TWEAK but more complicated and resonable in terms of price/quality of cause...
 
Sep 17, 2009 at 12:50 PM Post #13 of 60
hey thats cool man, I get it, I was you one day as well, but thats the way it works here. if you wish to advertise here you must contact jude; the forum administrator. when you get the circuit boards and BOM happening I would be interested to try it out for myself (not finished product, but just boards; I can do the work. I assume it needs a mod firmware as well?? or is standard RB FW enough??
 
Sep 17, 2009 at 12:58 PM Post #14 of 60
Quote:

it needs a mod firmware as well?? or is standard RB FW enough??


From what i have heard it works well with rockbox; however, rockbox doesn't supports 24-bit audio out-of box, so SQ is not as great as it could be. Some guys from this mod's team are writing patches to rockbox to get 24-bit audio support.
 
Sep 18, 2009 at 5:26 AM Post #15 of 60
aleXmod works very well at standart RB firmware.
You'll have a DAP with almost all lossless formats acceptable, gapless playback, cue playback, picture flow and so on with sound quality increadible for portables.

P.S. It's sad to say but our programmer sent me an information the original CPU of X5 couldn't sent data in 24bit I2S format. So it has a hardware limitation in 16bit. It isn't a problem when not using rockbox DSP modules ( EQ, pre-cut and so on), just listening for a music as is on HD580-600. When using high sensivity, low impedance IEM, there is a need to decrease the volume in DSP (digital domain). It is possible to pre-cut it in RB DSP module. So possible degradation in LSBs could occur dependin on how the procedure of pre-cut in RB has been realised.
 

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