[lantian]

Did you mean the internal board to chassis screws on Max ?

Internal board on dx220 normal one though imagine max has the same size ones there.
Thanks

 

[lantian]

A small update for my amp7 changed the audio note kasei polar one 50uf16v to bipolar ones 22uf16v and added a couple of vishai smd polymers for the power smothing to bring the total up to 1740uf. Somehow felt it was really needed to have the large reservoir for amp7. The bipolars are a massive step up from the polarized ones. Who ever is considering audio note Kasei for line smoothing, go straight for the 22uf16v bipolars. Will not miss a thing in comparison just get more. The midrange and depth are on another level.
Next month hope to be able to finaly do the whole smd caps on amp7 and have the whole 227ex package to be on the same level as 228ex. Thanks @Whitigir this combo is like nothing else out there. To bad i no longer posses any of my 300ohm cans.

 

[orys]

Anyone selling a modified amp8 guys? PM me.

 

[Lohb]

Modified Amp8 for sale...
https://www.head-fi.org/classifieds/ibasso-dx200-dx220-amp-8-card-heavily-modified.5525/

 

[justroya]

Thank you to @bden59 for helping me to enable the EX modifications for DX220. The goal is to preserve bass slam, timbres density, further enhance them in controls, dynamic and punches, improving clarity, details, trebles extensions.

There will be 2 parts of the EX just like Dx200.

Disclaimer: by modifying your unit, you risk permanently damaging your dedicated player, and you are sure to void the warranty. Only proceed when you are ready to lose your player and take all the risk as a man wearing his pants **. To anyone who can and will perform these modifications, please keep in mind that it was developed for enthusiasts and by enthusiasts, so please keep the labor reasonable.

1/ part 1: Hardware Modifications

You will need
https://www.mouser.com/ProductDetail/80-T543B107K010TE150
3x of those
https://www.mouser.com/ProductDetail/80-T543B227K6AHW35
2X of those
https://www.mouser.com/ProductDetail/80-T520A226M10ANE080
2X of those
https://www.mouser.com/ProductDetail/80-T520A107M006AT
4x of those
https://www.mouser.com/ProductDetail/80-T527I476M06ATE200
4x of those

You will replace a total 15 capacitors and 5 different values

Layout is as in the pictures. Ask if any questions

Tips: in order to open up Dx220, you need to take out the Amp module. There will be 2 screws with 1 under the warranty label. Unscrew then, then use a sucker to split up the back from the side of the 2 screws. It will be a bit tough to get it in and out.

*tape the side buttons up* or else they will come loose and give you some funky business. Remember to take out the MicroSD

After unscrewing 4 screws, and remove ribbon cables (only 2) .... Lift the PCB from the bottom from side to side with a tweezer, be patient as there are cooling thermal plaster which keep it attached to the back chassis. Then push in the SPDIF uptop and take out.






2/ Part 2 is TDK noise absorbing sheets. You will apply it upon IC chips similar to DX200EX

Hi Whitigir...wondering which 5 valves you mention was to be replaced? Was that canceled because of outdated or by other reason?
And I am also asking help on the un-labeled inductor's inductance... Cause i was screwed up 2 of that by squeeze more cap in my amp8...but i don't have any equipment to test those inductor...so if you can tell me that?

 

[Whitigir]

Hi Whitigir...wondering which 5 valves you mention was to be replaced? Was that canceled because of outdated or by other reason?
And I am also asking help on the un-labeled inductor's inductance... Cause i was screwed up 2 of that by squeeze more cap in my amp8...but i don't have any equipment to test those inductor...so if you can tell me that?

Hello, it have been so long that I haven’t touched the Dx220 (the published details is the most recent one). I also never got around to those inductors as it was never damaged. You may want to ask Ibasso directly ? I think there were a couple members who had similar encounters and solved it, but I can’t remember exactly. May be they still reading the thread and give some insight

 

[justroya]

Hi guys, AMP8 excellent amplifier. I recovered a schematic for it

Finally get the idea how this mod works...really need to omprove my ability of reading diagrams. hope i will have time to do this tonight. I've been miss the sound of amp 8 for so long.

 

[justroya]

BTW, I am trying to upgrade the oscillators on my dx220..do anyone have commend on replacing an oscillator?

 

[justroya]

I am recently keep studying my dead dx220’s PCB, and try to figure out how they work and react between each others. ICs, caps, inductors, resistors, regs, transistors, op-amps.....until last week I had find something interesting on the oscillator.


Blue circles in alphabets are crystals without power supply, I had not research on them yet. Red circles in numbering are our main characters - Oscillator.
(Head-fi forbidden my for posting photo, because I am new??)

https://www.dropbox.com/s/m545srw9wvk5rx4/1.png?dl=0
https://www.dropbox.com/s/jql7cjjn313kulm/2.png?dl=0

Oscillator_1&2
https://www.dropbox.com/s/8setuzee4g9ihz0/3.png?dl=0

Oscillator_3&4
https://www.dropbox.com/s/5pt2suf3jlct4l7/4.png?dl=0

Oscillator_5
https://www.dropbox.com/s/8a906geaojq1vk4/5.png?dl=0

Search components by thier marking was bored and weary. Especially when it comes together with a disappointing result. I started with the most important part (OSC 1&2) which serves our ESS9018 DAC chips, but it was much more difficult than I thought. I had searched for days, but there was no result by marking, neither from google or china network. That makes me gave up on the oscillators and put my mind on other “easier” components for a long time.

When I come back to the oscillators part, that was already a month later. I did the search again, still nothing comes out. It was weird. Cuz I remember that the oscillators in dx220 was not a “nobody”, indeed that were a “sounds very famous brand’s powerful low noise oscillators”(not offence, I was so ignorance about oscillators and how they works, let alone those brands).

So I visited the official web site.
https://www.dropbox.com/s/70g5rs2g3vqbs42/6.png?dl=0

Now I have the brand, I search on google, no result but a barely empty official site, switch to baidu (CN network), search again, no result but a barely empty official site.
Search on Mouser : Nothing
Search on Dxgxkxx: Nothing
Search on XX Components : Nothing

At the moment when I thinking if the“sounds very famous brand" and the "powerful low noise oscillators” was kidnaped by aliens, I find a clues on the CN audio DIY forum. That was an argument about comparing 2 OCSs in audio usage. The first one was the most famed OCS brand’s star that I’ve heard many time when I search about OSC “Crystek - CCHD” And the second one is....AS318-b.

That’s much enough about the searching story. After that I realize this “Accusilicon” is not a leading brand in OSC’s field, not even a middle one. It was a PRC factory with a US address but nobody know them in US....and recently takeover by "XiaoMi". Beside that this company is more like a urban legend spread around audio lovers and DIYers in CN. by “Crystek - CCHD" beated quality with 1/3 of it’s price”. And I also find many CN’s DAP factory are now using this OSC.

Happy ending? Not yet, I’ve got my OSC with clear marking “AS318-v3P” but not “AS318-b”...... After research of ICs for months, I find a patten of the IC's part no. that normally, when a IC has a "B" at the end of part no. it means.....
https://www.dropbox.com/s/2vxuho1jg0kb47h/8.png?dl=0

As Expected (Thanks google translate for the easier quoting)

 

[Whitigir]

I am recently keep studying my dead dx220’s PCB, and try to figure out how they work and react between each others. ICs, caps, inductors, resistors, regs, transistors, op-amps.....until last week I had find something interesting on the oscillator.


Blue circles in alphabets are crystals without power supply, I had not research on them yet. Red circles in numbering are our main characters - Oscillator.
(Head-fi forbidden my for posting photo, because I am new??)

https://www.dropbox.com/s/m545srw9wvk5rx4/1.png?dl=0
https://www.dropbox.com/s/jql7cjjn313kulm/2.png?dl=0

Oscillator_1&2
https://www.dropbox.com/s/8setuzee4g9ihz0/3.png?dl=0

Oscillator_3&4
https://www.dropbox.com/s/5pt2suf3jlct4l7/4.png?dl=0

Oscillator_5
https://www.dropbox.com/s/8a906geaojq1vk4/5.png?dl=0

Search components by thier marking was bored and weary. Especially when it comes together with a disappointing result. I started with the most important part (OSC 1&2) which serves our ESS9018 DAC chips, but it was much more difficult than I thought. I had searched for days, but there was no result by marking, neither from google or china network. That makes me gave up on the oscillators and put my mind on other “easier” components for a long time.

When I come back to the oscillators part, that was already a month later. I did the search again, still nothing comes out. It was weird. Cuz I remember that the oscillators in dx220 was not a “nobody”, indeed that were a “sounds very famous brand’s powerful low noise oscillators”(not offence, I was so ignorance about oscillators and how they works, let alone those brands).

So I visited the official web site.
https://www.dropbox.com/s/70g5rs2g3vqbs42/6.png?dl=0

Now I have the brand, I search on google, no result but a barely empty official site, switch to baidu (CN network), search again, no result but a barely empty official site.
Search on Mouser : Nothing
Search on Dxgxkxx: Nothing
Search on XX Components : Nothing

At the moment when I thinking if the“sounds very famous brand" and the "powerful low noise oscillators” was kidnaped by aliens, I find a clues on the CN audio DIY forum. That was an argument about comparing 2 OCSs in audio usage. The first one was the most famed OCS brand’s star that I’ve heard many time when I search about OSC “Crystek - CCHD” And the second one is....AS318-b.

That’s much enough about the searching story. After that I realize this “Accusilicon” is not a leading brand in OSC’s field, not even a middle one. It was a PRC factory with a US address but nobody know them in US....and recently takeover by "XiaoMi". Beside that this company is more like a urban legend spread around audio lovers and DIYers in CN. by “Crystek - CCHD" beated quality with 1/3 of it’s price”. And I also find many CN’s DAP factory are now using this OSC.

Happy ending? Not yet, I’ve got my OSC with clear marking “AS318-v3P” but not “AS318-b”...... After research of ICs for months, I find a patten of the IC's part no. that normally, when a IC has a "B" at the end of part no. it means.....
https://www.dropbox.com/s/2vxuho1jg0kb47h/8.png?dl=0

As Expected (Thanks google translate for the easier quoting)

Accusilicon is not a brand name, but it has very respectable measurements and performances over other brands. Anyways, welcome to the fun parts of looking up for OC. When speaking about OC, there are ways more to take in consideration than just pull and replace.

 

[justroya]

My Amp8 is still waiting for me, so I will say it in short form.

1) I had searched for days to purchase the "AS318-b" in 2520 case but failed. I am trying something off label. If I success, I will post the method for free, or I may start a group purchase if in needed.

2) My "AS318-b" is on the way, they will replace the stock "AS318". Once if I finish the replacement, I will update the status no matter Success or Fail.

3) If the "AS318" replacement success, I may further think of replace the stock 4x mhz pair of OSCs, the part no. & datasheet link as below

"NDK - NZ2520SD"
https://www.digikey.hk/Site/Global/Layouts/DownloadPdf.ashx?pdfUrl=A3744E4855F046779A5DD222DABCDE94
"Accusilicon - AS318-b"
http://www.accusilicon.com/docs/AS318BM.pdf

they were in the exactly same frequency, both work in 3.3v, but other data are too difficult to me to understand, and I had no experience of replace OSCs, so I can't expect the result of replace by a different brand or what so ever different OSC. If anyone tried, please comment.


PS) It feels so amazing...spending weeks to figure these out, hours to posting them for free.
@Whitigir you mush been gone through this many time, thank you for sharing your amazing thoughts.

 

[justroya]

Accusilicon is not a brand name, but it has very respectable measurements and performances over other brands. Anyways, welcome to the fun parts of looking up for OC. When speaking about OC, there are ways more to take in consideration than just pull and replace.

What? I found the home page of it with the datasheet of "AS318-b" in it.
http://www.accusilicon.com/cn/asic_and_module/xo.html

To your anyway, I think I am still way too far from talking about techs, data, advantage/disadvantage of replacement, that I was still standing out of the door. but this time, or say this MOD, seems different, that is more like replacing OPA627AP to OPA627BP. still in risk of cause, especially I can't find the Datasheet of stock "AS318", but at lease the risk is much lower and worth trying now. And not to mention, remember that I have really plenty of spare parts?

 

[justroya]

Here's an article by IBASSO, translated by Google translate, forgive google if the translation is not accurate.

Audio indicator science popularization from IBASSO
This article is officially authorized by ibasso to reprint, the original title "Scientific HiFi Talk 3-How to Read the Parameter Chart of Digital Audio"

After entering the digital Centry, the storage/transmission of analog electrical signals is gradually replaced by digital signals. Storage and transmission in the form of quantization as a digital signal has the advantages of less resource occupation, high fault tolerance, strong anti-interference and so on. However, our human body’s perception of the world is still “simulated” and “continuous” (in fact, the signal transmission inside the organism also has a quantitative process, and the world is not continuous in nature, but now we don’t need to discuss this kind of micro-physics. model). Therefore, digital-to-analog conversion has become a very important link in electronic information engineering, which needs to be involved in communication engineering, signal processing, automation and control, and so on. Electronic engineers meticulously design and develop various ICs and circuits to improve the accuracy and performance of DA/AD, especially for electro-acoustic systems.

The core component responsible for digital-to-analog conversion in an electroacoustic playback system is the DAC chip. Whether it is a traditional R2R current addition type DAC or an SDM integral interpolation type DAC, all have certain requirements on the quality of the input digital signal.

Clock and crystal
8 years ago “Colorfly” C4 uses a dual-frequency crystal oscillator and FPGA to solve the distortion caused by re-sampling, that is, SRC, portable HiFi players and even mobile phones have begun to popularize dual crystal oscillators, and slowly add CPLD or FPGA control logic to control the clock signal Perform synthesis and processing. Up to now, high-end portable HiFi players have begun to promote "femtosecond crystal oscillators" just like desktop devices. In publicity, the Jitter real-time basis error is always taken as a very important publicity point, and many digital audio engineers or senior audiophiles will tell you that the Jitter value is actually not as important as the phase noise. What has actually happened?

The relationship between "femtosecond" crystal oscillator and phase noise
First of all, we must know that phase noise itself does not refer to a kind of noise, but a random change in the phase of the system output signal caused by the system under the action of various noises. It is a kind of "error", which is a measure of the stability and accuracy of the frequency source. An important indicator of sex. The method of expressing this kind of error is to express the random changes of different error amounts separately, which forms a phase noise map. Let's look at an example:

The above picture is the phase noise diagram of the famous femtosecond crystal CCHD-575 100MHz. You can see that the abscissa in the figure is Hz, which is the offset frequency. The offset frequency is relative to the carrier frequency, which is the operating frequency of the clock itself. In an ideal state, a crystal oscillator working at a frequency of 100MHz as shown in the figure should have an equal interval (10ns) between each oscillation to accurately output a square wave. But the reality is that every output of the crystal oscillator may be faster or slower than its intended position, and the corresponding frequency will be higher or lower.

If the output frequency is 100.0001MHz at this time, the frequency will be 99,9999MHz or 100.0001MHz after the frequency offset by 100Hz. The above figure indicates the phase noise level at 100Hz-121dBc/Hz, that is to say, the power of 99,9999MHz and 100.0001MHz (±100Hz) output frequency, the proportion of the total output power is 0.000089% per Hz. The reason why it is dBc/Hz rather than simply dBc is to make it uniform according to frequency, because the power ratio at different frequencies is different. The phase noise diagram is a complete expression of the clock frequency stability quality in the frequency domain, and of course it can also be simplified into a numerical expression in the time domain-Jitter. The calculation method is similar to the method of calculating the value through the THD curve, that is, the phase noise-frequency curve is integrated, but to get the Jitter, the hexadecimal conversion is required. In actual engineering applications, in order to avoid complicated calculations, the integral is simplified to area calculation, as shown in the following figure:

Since it is an integral (area calculation), then the upper and lower limits need to be defined. For audio crystal oscillators, the industry usually uses 10-1MHz integral upper and lower limits, while communication crystal oscillators often pay attention to the performance in the 12kHz-80MHz bandwidth. For timing circuits and systems, they pay more attention to the longer-term accuracy of the crystal oscillator (in fact, it can also be determined by the phase The noise figure is obtained by integration, but generally another measurement method is used, which will not be discussed here). In the datasheet of the "femtosecond crystal" AS318B, which is almost universal in high-end portable HiFi players, the official Jitter value under these two integration bandwidths is found, and the corresponding frequency point of 100MHz, 12kHz-80MHz The jitter value is only 71fs, which is lower than the nominal 82fs of CCHD-575.

The choice of common active crystal oscillator
Here are a few of the more common active crystal models in portable HiFi players, and make a simple comparison.

1) CCHD-575/CCHD-957 - Crystek
This is the second-generation femtosecond crystal of Crystek, an established crystal oscillator. It is an optimized product developed after the first-generation femtosecond crystal CCHD-950 was used in HiFi audio applications. The difference is that CCHD-957 is a dedicated audio frequency crystal oscillator, which can only achieve 49.152MHz, while CCHD-575 can achieve 100MHz, but the near-end phase noise is slightly inferior to CCHD-957. Generally speaking, it is very A good crystal oscillator, there are many high-end desktop decoders used.

2) AS318/AS318B - Accusilicon
AS318B is a femtosecond crystal oscillator launched by Accusilicon, which is better than Crystek's CCHD series. But AS318 and AS318B are not the same model, they are low-precision versions, used in mobile phones, communications and other electronic devices.LeTVMobile phones have used AS318. Both are available in three packages, 2520 is mostly used in portable players , SMD1409 is used in desktop devices, and DIP14 is in-line package. The excellent phase noise of -100dBc/Hz@10Hz makes AS318B the first choice for high-end HiFi players.

3. NZ2016SDA / NZ2520SDA / NZ3225SDA - NDK
NDK's NZ series crystal oscillators claimed to have the lowest phase noise in this volume when they were released. From the official datasheet, it is indeed very good. The frequency of 45MHz and 49MHz is almost equal to the phase noise level of AS318B. But NZ-SDA can also achieve frequencies below 26MHz (22MHz/24MHz), and AS318B has no choice of low frequency, so NZ-SDA series can be said to be the best choice for CS series DAC.

4. DSO221SH series - KDS
A product of KDS, another Japanese crystal oscillator manufacturer. The Japanese naming crystal products are very straightforward, and usually put the package directly into the name. Although DSO series crystal oscillators also use names to distinguish packages directly, they are not named after packages. It is easy to confuse people. If you are interested, you can find them. The crystal oscillator used for audio in their home is not excellent, and is often taken out by the MEMS crystal oscillator.

5. SiT8208 - SiTime
This is SiTime's newly launched MEMS silicon crystal oscillator. Unlike a quartz crystal, it does not require precise temperature compensation or shock absorbers. It also has excellent long-term stability, very slow attenuation, low remote phase noise, and good anti-interference performance. However, in fact, because the near-end phase noise of MEMS silicon crystal is not good enough, it is obvious for high-end HiFi applications. Effective Can't catch it.

 

[justroya]

Okay.....its 3am in the morning and i don't know how to say goodbye.....(Lyrics)
gotta go to sleep, hope I will have time with my AMP8 tomorrow.

 

[justroya]

D