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  1. abartels

    R2R DA M1 Ultracap powered build

    A huge improvement!!!!!
  2. abartels

    R2R DA M1 Ultracap powered build

    Superaps / Ultracaps have a VERY long life expectancy, if used correctly. They can easily cycled 1.000.000 times before esr rises to an unacceptable value, depending on your design. They have an INFINITE shelf life. One cycle contains 1x fully charging and 1x fully discharge. In hour...
  3. Burson V6 Vivid - Classic upgrade for DAC

    Burson V6 Vivid - Classic upgrade for DAC

    A few years ago I came across Burson opamp products. I contacted Charles at Burson, and fortunately he was willing to send me a sample of V5i Dual Hybrid opamp. After a burn-in period of 6 days I listened to this opamp and was very surprised of it's overall sound quality. I compared with...
  4. abartels

    The Zishan dsd's corner

    Search at ebay
  5. abartels

    The Zishan dsd's corner

    https://www.ebay.com/itm/Upgraded-version-Zishan-DSD-HIFI-fever-portable-lossless-music-player-AK4497-/273635649439?_ul=NL
  6. abartels

    The Zishan dsd's corner

    I have 250gb spread over 500 folders, no problems at all unless i stress device with pushing buttons too quickly
  7. abartels

    The Zishan dsd's corner

    All files in one folder?
  8. abartels

    The Zishan dsd's corner

    Opa1612 doesn't seem a good contender, at least not for HP amplification. Whitepapers show a series resistor of 100 Ohm. To me it looks like it doesn't have shorting protection. http://www.ti.com/lit/ds/symlink/opa1612.pdf Why not using balanced output with AD8620? Works great, just need to...
  9. abartels

    The Zishan dsd's corner

    When I received my Zishan, I charged it while listening and encountered same problem, it got charged only about 50%. After I switched it off and charged it, it went to 100%. Not sure if it was immediately or after a few times charging and discharging. Mine now charges to 100% even if listening...
  10. abartels

    The Zishan dsd's corner

    HE400i sounds terrific on balanced output! They are available for USD179!!! https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F253238435384 Buy the Defean Lambskin angled pads at AE, they make the HE400i sound even better, more open and more sub bass.
  11. abartels

    The Zishan dsd's corner

    i removed them and soldered wire on the pads
  12. abartels

    The Zishan dsd's corner

    Graph about Vref from Arduino site, taken from AKM whitepapers:
  13. abartels

    The Zishan dsd's corner

    the other cap values are correct, except for VrefH(L/R) to VrefL(L/R) Unit is deadquiet, no background noise.
  14. abartels

    The Zishan dsd's corner

    I removed 4x10 ohm resistors, sq is definitely better, especially bass output is much better About the 10uF value for vrefh to vrefl (both channels), this was also in whitepapers of 4490 and 4495, values of 10uF, as well in whitepapers of evaluationboard of 4495, BUT in whitepapers of...
  15. abartels

    The Zishan dsd's corner

    You are right! Also strange standard version has 22ohm resistors, just checked AD8620A datasheet, it has indefinite shorting protection, will short my 10 ohm resistors and try how it sounds with my HE400i and KZ-ZS10. Btw, have my HE400i balanced connected, sounds great! KZ-ZS10 sounds great...
  16. abartels

    The Zishan dsd's corner

    Those 100uF caps are part of it's low pass filter Also VERY important, caps used for Vref, between VREFHL-VREFLL and VREFHR-VREFLR, they must preferably be 2200uF or higher value. I know there's not sufficiant room for high values, but must try as high as possible. In my previously build...
  17. abartels

    The Zishan dsd's corner

    Does differential output of 4497 need coupling caps??? Very strange, will have a look at the whitepapers
  18. abartels

    The Zishan dsd's corner

    You could damage the opamps, but I really think they aren't necessary. Be sure to connect your hp's before powering on Zishan. Don't remove the resistors, just solder 4 short pieces of wire on their top to bridge them, or, solder second smd resistor's on top of them (parallel)
  19. abartels

    The Zishan dsd's corner

    Man oh man, how many times do i have to upload and post pictures of Standard version (the above is STANDARD) and Upgraded version..... Upgraded version has NO 4 electrolytics but 4 SMD caps, and i suppose these are bypass caps for psu and not coupling caps. In schematics it shows balanced output...
  20. abartels

    The Zishan dsd's corner

  21. abartels

    The Zishan dsd's corner

  22. abartels

    The Zishan dsd's corner

    you mean the modified version with 2xopa275 replaced with 2xAD8620 and other caps, and voltage of opamps cranked up from +/-9V to +/- 12V? No idea what output impedance is
  23. abartels

    The Zishan dsd's corner

    Thanks for explaining to me, didn't know this, will read more on this subject
  24. abartels

    The Zishan dsd's corner

    How could one of the negative channels reach a 15v positive level? And both negative outout pins are flowing
  25. abartels

    The Zishan dsd's corner

    Removed
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