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iBasso DX50 MODS

Discussion in 'Portable Source Gear' started by babs, May 27, 2014.
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  1. jazzwave
    So, which you prefer to change for 1st mod; LO or HO caps? I have 32 Ohm and 300 Ohm cans
  2. babs

    I am already changed the HO decoupling cap; the 3x47uF oxicaps are gone and I put one 330uF 10V POSCAP (#10TPE330M)
    This cap fit nicely to the original pads
    Bass seem tighter, and go definitively lower
    For the HO OP amps, I recommend the model I put on my DX50: the ADA4897-1ARZ
    For the LO OP amp, I don't recommend the model  I have installed on my DX50 (ADA4896-2); too difficult to solder correctly this small package
    But the ADA4841-2YRZ seem equivalent and have the good package (SOIC-8)
    Changing HO OP amps give me more punch and bass
    Changing LO OP amp give me lower distortion and better imaging
    But its just me...
    CoiL likes this.
  3. CoiL
    Thanks! This will be first thing I do. Next will be HO opamps and then lo opamp.
    Have You tried this Yourself on Your modded DX50 or just recommendation?
  4. babs
    I have not try the ADA4841-2, just a recommendation
  5. CoiL
    Thanks again! :wink:
  6. CoiL
    Any particular reason why You went with 330uF 10V POSCAP (#10TPE330M) instead 220uF 10V (stock caps spec) POSCAP (#10TPE220MIL) ?
    330uF vs. 220uF poscap:
    ESR - 25 mOhms vs. 18 mOhms
    Leakage current - 330uA vs. 220uA
    Ripple current - 3000mA vs. 2800mA
    Anyway, I ordered #10TPE220MIL and will report back after installing.
    Are You still using oxicap there or also replaced it with POSCAP?
  7. polyrhythm
    Regarding change of Dual Differential Amplifier I think this might be a worthy upgrade:

    JRC: MUSES8820E


    maybe it is not suitable though to be positioned in the circuit straight after the DAC? Babs any thoughts.....?

    2 x HO single amps will probably still be:


    Like you Coil I am going to do the HO decoupling cap next and then tackle the main amp section.

  8. CoiL
    For differential opamp decoupling cap I ordered POSCAP in both cases D2E (# 6TPE100MI ) and B2 (# 6TPE100MPB).
    Will try to fit D2E in that position because it has very good specs: ESR 18, ripple current 2800.
  9. polyrhythm
    so are you experimenting with these as well as the ones you stated earlier?:
    100μF vs 220μF
  10. CoiL
    No, for HO decoupling cap I`m going straight with # 10TPE220MIL. I prefer to stay in original values and it has littlebit better specs than the one babs used imo (better ESR, lower leakage current and ripple is almost same). I already have it ready on my table for soldering but will wait for HO opams.
    Previously I was thinking about using 2x100uF 10V (# NOJD107M010RWB) http://eu.mouser.com/ProductDetail/AVX/NOJD107M010RWB/?qs=E%2F%2FhvbtCqpPbHFa5iD7IhQ%3D%3D
    but my local electronics parts dealer doesn`t offer them and I don`t bother to order from internet and pay for transport.
    Now I discovered POSCAP thanks to babs and going to use # 10TPE220MIL Poscap.
    For DAC differential opamp decoupling cap I`m trying to fit # 6TPE100MI (larger D2E case) first. If I don`t succeed, then going to use # 6TPE100MPB (smaller B2 case).
    Would try some oxicaps also but I can order them only by 5pcs min and cost is going to be too high. 
    For that place babs used #NOSB226M006R0600 (he hasn`t answered to my question yet if he is still using it or also changed to Poscap):
    NOSB226M006R0600 vs. 6TPE100MI vs. 6TPE100MPB vs. stock TAJB107M006RNJ
    ESR- 600 mOhm vs. 18 mOhm vs. 25 mOhm vs. 1700 mOhm
    Leakage current - 2.6 uA vs. 63 uA vs. 63 uA vs. 6.3 uA
    Ripple Current - 412 mA vs. 2800mA vs. 1600mA vs. 224mA
    I`m not sure if those Poscaps leakage current will be a problem? I know that in coupling application leakage current should be low as possible but with decoupling?
    I hope babs has time to answer. 
    Another option would be TA series Poscap # 6TAB47M which has half lower leakage current than TPE series Poscap: http://eu.mouser.com/ProductDetail/Panasonic/6TAB47M/?qs=r271rpOLewslPGukLYfMHA%3D%3D
    This one has following specs: ESR 70 mOhm, Leakage Current 29.6 uA, Ripple Current 1100 mA
    But it is new product and again my local dealer has problems - not offering it atm, so no go for me ;(
  11. babs

    No, I change de LO decoupling cap for a POSCAP: 6TPE220MAZB  (220uF, 6.3V)
    this is more capacity than the original cap (100uF) but all seem OK, power supply didn't crash at all
    Not sure of the improvement, maybe better separation, but Its just an impression
    I buyed 10 of these caps, so I decide to try to change the decoupling caps of the DAC analog power supply; same case, same voltage
    There is 3 analog power supply pins on the DAC: AVDD (pin 15), AVDDR (pin 9) and AVDDL(pin 20)
    These caps are located at left on the photo:

    The LO decoupling cap is just above the differential amplifier
    The 3 DAC decoupling caps are vertically aligned on the left of the picture
    No possible error; these 4 black caps have an big (+) on it
    I didn't expect lot,but I am surprised; there is a clear improvement: less noise and better separation of instruments
    I keep it!
  12. babs
    The dual differential OP amp must be an RRIO (Rail to Rail I/O) low voltage amplifier, the MUSE8820 is a high voltage amplifier (+/-3.5V to +/-16V)
    And he is not RRIO at all, so I don't think it will work, and if it work, it will be at the limit, not recommended...
  13. CoiL
    LOL, every time we are dealing with "old" capacitors change, You already have new mods ;D
    Since You used 6TPE220MAZB for LO differential amp decoupling cap then I assume leakage current isn`t problem
    because the one You used has it 138.6 uA which is over double higher than the one I`m going to use (# 6TPE100MI or 6TPE100MPB).
    Now I have to order some more Poscaps for  decoupling caps of the DAC analog power supply :wink:
  14. babs

    For the LO decoupling Cap, I don't think that the value of the cap will be so important, I change an 68uF Oxicap for an 220uF Poscap without big sonic différences
    These amplifiers drive an high impedance load, no need for lot of current
    I think that the main différences will be the ESR and the DF of the caps, and your 100uF have lower ESR that my 220uF
    Try your 6TPE100MPB before buying more caps
    For the HO decoupling Cap, the value is more important, and affect directly the bass response
  15. CoiL
    Ok. Thanks for the information!
    Will give little summary so that other readers/modders don`t get so confused who and what caps are going to use. Here are all the caps I`m going to use:
    HO decoupling cap - # 10TPE220MIL (7343 case)
    DAC differential amp decoupling cap - # 6TPE100MI (7343 case) or # 6TPE100MPB (3528 case)
    I ordered both and trying to fit larger with better specs.
     DAC analog power supply decoupling caps - # 6TPE100MI (7343 case) or # 6TPE100MPB (3528 case)
    I ordered both and trying to fit larger with better specs.
    Lol, I think we can call this whole capacitor overhaul as PANAMOD because all caps (LO&HO coupling caps also) are Panasonic`s ;D
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