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Are you computer audiophile? If so, Fidelizer will help you enjoy the music on computer even more.

    Portable Products

    Portable Products


    I started my audiophile journey around the time they founded iRiver company as a headphile first. Since then, I’ve been on this headphile road long enough to see the rise and fall of iRiver before being rebranded to Astell & Kern which is most popular digital audio player today.

    During this journey, I’ve indulged myself with many interesting projects such as optimizing ROM giving something market can’t offer. As you may already be familiar with Fidelizer, optimizing ROM can give unique improvement with great musicality.

    But that’s not all. I also modify many portable products from building cables, modifying DAP’s hardware too or even tuned earphone’s crossover. As a result, I gained many invaluable experience from fun experiements with headphile friends in Thailand.

    Now I think it’s good time to introduce these projects to worldwide scale with professional modding and services from maker of Fidelizer who get his Nimitra product featured in Stereophile’s cover and claimed many great awards and reviews worldwide in just one year.


    Fidelizer Purist ROM


    Fidelizer - Purist ROM


    I received requests from Fidelizer users from time to time about making Fidelizer for Linux platform. You may not believe it but I’ve been working on Fidelizer for Linux project for over 3 years. Now it reaches maturity to be released for supported devices worldwide.

    As for why I never mentioned this before, I have a proper conclusion from my long years of research. When I compared computer transport to Esoteric transport, it was only Windows platform that could provide satisfying performance as you can hear from Nimitra product.

    Also, each device in Linux needs specific optimizations such as supported governors and schedulers, root access, and specific tweaks with different hardware. It’d be hard to create multi-purpose utility. But for Android DAP, it’s possible with Purist ROM for supported devices.



    -Play Store and Apollo – Fidelity Edition added (If applicable)
    -Build configuration tweaks for better video and storage performance and improve battery life
    -Bundled audio effects removed but keep main engine (For Poweramp that rely on audio effects)
    -Some specific tweaks maybe added for important improvements


    Supported devices (installation instructions will be provided inside):

    iBasso DX50/80/90
    iBasso DX100
    iBasso DX200
    Fiio X5iii
    Fiio X7
    Fiio X7ii

    Since 1st October 2017, Fidelizer ROMs has PerfectDynamics Sound Optimizations applied as a major update. Please contact Fidelizer if you’re Enhanced or Advanced ROM users and haven’t received yours yet.


    Hi Keetakawee

    Thanks for the Fiio X5iii 1.1.7 firmware update, it sounds very nice.

    Many Thanks



    The reason I created Purist ROM is fix issues and improve performance in stock ROM helping users to appreciate the product better. Receiving message like Purist ROM saving someone from selling his device is meaningful enough for me to keep doing this for free.

    Just like Fidelizer, if Purist ROM works great for you, you can upgrade to Enhanced / Advanced Purist ROM with personal download link after purchase. I will continue to maintain these projects with most recent version from manufacturers.


    • Fidelizer - Enhanced ROM

      Only US $49.95


      Enhanced ROM is affordable services with additional enhancements.

      You’ll receive the following improvements:

      1. All features from Purist ROM included
      2. Kernel optimizations for audio I/O and remove non-audio services
      3. ฺFull Build configuration optimized for better sound quality
      4. Non-audio components de-bloated for dedicated audio platform
      5. ROM cooking support for troubleshooting services

    • Fidelizer - Advanced ROM

      Only US $99.95


      Advanced ROM is uncompromised services with finest enhancements.

      You’ll receive the following improvements:

      1. All features from Enhanced ROM included
      2. Applied low-level system/kernel optimizations for best sound quality
      3. Audio driver configuration optimized for neutral sound reproduction
      4. Optimized system libraries improving system performance
      5. ROM’s priority between Purist / Compatibility / Battery Saving


    Why does ROM cooking services cost this much?

    I think it’s understandable for some people to think $49.95 and $99.95 USD being costly for cooking ROM. Here’s the reason why.

    1. I need to cook ROM with actual device in supported list. I even bought some for research purposes.
    2. It took a lot of time and effort to research and improve ROM optimizations to its fullest potentials, sometimes even weeks or months.
    3. For each customer, I need to repack up to 1GB system image, prepare the ROM and upload with his name.
    4. When new version comes out, sometimes it took up to whole week for preparing update, fixing bugs and refining ROM.
    5. Giving direct download link has risks for ROM being leaked. One customer can leak to hundreds and that did happen before.

    I also asked manufacturers for their approval to provide after-market ROM cooking services. It took a lot of time and effort with very exhausting works at times to cook the ROM for one person unlike to free version with only safe optimizations for all devices.


    Will flashing Purist ROM void warranty?

    Flashing Purist ROM won’t void warranty. However, it’s recommended to flash stock ROM back before sending back for services.


    Will I receive ROM update when new version comes out?

    When new version comes out, you can ask for ROM update and I’ll re-upload a new version for you. You can also request to make adjustments too.


    Upgrade Purist ROM today

    You can purchase Purist ROM upgrade by selecting upgrade options below. Please make sure to select correct device model before purchasing.

    Purist ROM Upgrade
    Device Model
    ROM’s priority (Advanced ROM only)
    Special instructions

    Fidelizer, Nimitra, and returning customers can order Fidelizer Purist ROM products with $5-10 refund discount for Enhanced and Advanced ROM.

    If your desired device isn’t listed in supported device list, please contact [email protected] for inquiry about new device support.


    Fidelizer Mod


    Fidelizer Mod


    There was a time when I suspended my headphile journey and went back to basic smartphone because sound quality from highend stereo system is too overwhelming. I ended up asking myself if I should invest more on stereo system instead of headphile rig when you can’t find any satisfying ones.

    One day, my friend sent me iBasso DX90 for modification since he didn’t use it anymore. With experience from modifying a few highend digital sources, I found it’s possible to bring reference system performance to portable device. It was a huge success and DX90 has become his favorite DAP since.

    I’ve been working on various hardware modification projects. With over 10 years of experience, I have 3 levels of modification as below.


    Reference – fixing issues with hardware and upgrade parts with my own design while making it affordable. Mostly upgrading some opamps, fine-tuning capacitors or resistors, or apply some tweaks to fix some sound signature issues.

    Signature – Once I get device sounding good with reference sound performance, signature mod will take it to further levels with upgraded parts such as opamps, capacitors or resistors with some higher quality ones improving sound quality further.

    Ultimate – This is for passionate audiophile who looks for cost no objective upgrade. Using finest parts, clock modules upgrade, and intensive tweaks that for ultimate sound quality. It’s not about costly stuff together but the best that works together.


    I modified both device and Amp module (which has soft mute circuit bypassed for better sound than not to)

    I can say that this one can go up all the way in the same level as SP1000cu/ss only that the house sound is not the same character.

    SP1000 both …



    With these principles in mind, you can see up to 3 levels of my finished modification projects from the following devices. The cost is for Fidelizer Mod alone. I’ll contact you and provide shipping information after receiving your order.

    You can also buy a new unit with Fidelizer Mod directly too. Additional cost will beadded according to device’s MSRP price. Fidelizer, Nimitra, and returning customers can order Fidelizer Purist ROM products with $50 refund discount for Fidelizer Mod products below.


    iBasso DX200


    DX200 - Mod


    After DX200 launch event, a few DX90 users with Fidelizer Mod have been waiting for DX200 version too. I thought it would be easy peachy since I already modified DX90 intensively with every possible upgrade I can think of but I was so wrong.

    The first issue is AMP1 module is quite small but it drives with 10V capacitors. Some even need 16V ones so what I thought it’d go well didn’t fit. It was a lot of hard work trying to fit the best possible capacitors I could find.

    I also worked on a lot of challenging tasks until I did the best I could. Here’s how I concluded DX200 modification project with 3 levels mod.


    Reference – Replaced stock 2 x 470uF Aluminum capacitor with a single 1,000uF capacitor improving transparency with full sound dynamics. All outputs also have soft mute circuit by-passed with high quality pure copper wire from output stage directly.

    Signature – In this level, I re-designed op-amp implementation with completely different set of 6 opamps. iBasso uses 4 of dual buffer opamps and 2 of output stage opamps. With new set of opamps, DX200 can perform closer to reference digital sources.

    Ultimate – This level will have all tantalum capacitors upgraded with more than 20pcs of the highest grade tantalum capacitors that can fit inside. It’s very costly but improvement is very rewarding. Some even asked to modify main DX200 body too after hearing this.

    DX200 Ultimate – This is DX200 unit with ultimate modification level as my masterpiece. It comes with ultimate modification soldering over 50 points for whole DX200 unit with Fidelizer Advanced Purist ROM as below.


    DX200 - Fidelizer Ultimate Mod


    -Fidelizer Advanced Purist ROM
    -Over 30 of capacitors upgraded with highest grade of tantalum capacitor
    -Clock modules are upgraded high quality ones from Japan for processor and XMOS interface
    -Re-designed op-amp implementation in AMP module with completely different set of 6 opamps
    -Soft-mute circuit by-pass for purist signal transmission in AMP module
    -Power capacitor in AMP module upgraded from 2x470uF to 1,000uF capacitor
    -Some tweaks for power supply and internal damping in main unit

    Fidelizer Mod for iBasso DX200
    Special instructions

    The greatest part about DX200 Fidelizer Mod project is you can purchase modified AMP module to use with stock unit so it won’t void your warranty.

    There’ll be signal’s burst when trying to play the first track similar to when you open iBasso DX50 with headphone connected in safe level so don’t worry.


    Fiio X5iii


    X5iii - Mod


    Fiio X5iii is the most bang of the buck DAP I’ve ever seen in history of my headphile journey. Not only it offers all outputs and connections like iBasso DX200 has offered, it also come with the same dual DAC used in AK380 and Android ROM for only $400 USD!

    After inspecting its hardware architecture, I found uses very good architecture design such as dual stage amplification for low-pass filter and amplification stage for balanced circuit. And it has 4 upgradeable crystal oscillators for ultimate mod level for crazy improvement!

    After working on ultimate Fiio X5iii modification project for a while, I can polish this gem with 3 levels mod as below.

    Reference – To compensate many features offered in unbelievable price, X5iii has some weak spots for parts quality. After listening observation, the first priority is to get Advanced ROM installed with upgraded highest grade tantalum capacitors to lift veiled and bland sound signature.

    Signature – I didn’t put opamps in X5iii in reference mod because original parts are quite good and capacitors deserve more attention. With completely new set of 4 opamps and some treatments, you’ll get full sound performance capable of driving full size headphones decently.

    Ultimate – X5iii has very good implementation of clock recovery. It has dedicated system clock, audio interface clock, and dual audio reference clocks upgraded in total. It will become a fearsome beast that can compete many flagship DAPs out there.

    Fidelizer Mod for Fiio X5iii
    ROM’s priority
    Special instructions

    Fiio X5iii is very affordable so it’s a device worthy of giving serious hardware upgrade to make good uses of great features to its fullest.


    Chord Mojo


    Chord Mojo - Fidelizer Signature Mod


    I love Chord DACs but not all of them hits all my sweet spots. Mojo has good punches of dynamics. Hugo is very analytical for high performance unit. Hugo TT is perfect combination of Mojo and Hugo but it’s also too large for portable device.

    I also heard new Hugo 2 which is a good compromise version of Hugo TT but it’s still too big for portable in my book. I think the best way to bring very analogue yet musical and colorful Chord sound signature as portable unit should be something that fits in your hand like Mojo.

    I started researching on Chord Mojo modification since June to deliver uncompromised performance for Chord Mojo as below.

    Reference – The reason why Chord Mojo has powerful sound yet a bit veiled is because it can push 720mW at 8 ohm load but I’m not sure if resistors can really handle at full load so I upgraded 6 output resistors with 1% tolerance, 750mW output and 2 highend grade capacitors used in DX200.

    Signature – I upgraded 2 input capacitors for USB charging and battery then tap battery directly to Mojo circuit board with high purity copper for full sound dynamics. I also replace additional headphone jack with 2.5 termination using best silver-plated contacts.

    I wish I could make Ultimate modification with Chord Mojo but I couldn’t find clock module worth upgrading from stock ones yet. Also, for about $300 modification cost for Signature level mod is surprisingly great enough for me to feel satisfied with decent DSD tracks from David Elias.

    -Upgrade 6 output resistor with 1% tolerance and 750mW output for uncapped performance at 8 ohm load
    -Upgrade 2 output capacitor with the same highend grade ones used in DX200’s Fidelizer Ultimate Mod
    -Upgrade 2 input capacitor for charging and battery with best ones for solid sound performance
    -Modify battery module to use direct connection with high purity copper wiring for full sound dynamics
    -Replace additional output jack for 2.5 termination with silver-plated contact for balanced ground topology design

    Fidelizer Mod for Chord Mojo
    Special instructions

    I hope you’ll love Hugo-like improvements and 2.5 jack support with Fidelizer Mod for Chord Mojo. It’s truly a game changer device worth upgrading.


    If you want to send your unit to us for modification, please contact [email protected] so I can arrange some good offers for you. I’ve been modding hundreds of portable products and a few highend ones too so feel free to ask anything about modification project.