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The Zishan dsd's corner

Discussion in 'Portable Source Gear' started by neog007, Nov 17, 2016.
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  1. Merlin-PT
    I always double check the PCB paint, with the position of capacitor that was soldered in there and the meaning of it's polarity markings.

    See the bellow wikipedia picture text:
    In non solid electrolytic capacitors the line/mark in the capacitor identifies the negative - capacitor side.
    In solid electrolytic capacitors the line/mark in the capacitor identifies the positive + side.

    This wikipedia picture is worth a thousand words:
    https://en.wikipedia.org/wiki/Capacitor_types#Polarity_marking

    So in the photo I posted the white line in the stock solid capacitor is the positive (+) PCB pad.

    Note: With circuit power on, we can also use a multimeter to find the voltage polarity at the caps legs.
     
    Last edited: Mar 19, 2019
    DBaldock9 likes this.
  2. AxelCloris Administrator
    Please keep the discussion focused on the Zishan DSD and not one another. Thank you, everyone.
     
  3. nesty
    Hi @Ivan TT , on item#5, you mentioned there are four capacitors around the lpf opamps... may we know the value of these capacitors and type? thanks
     
  4. DBaldock9
    I think he's talking about the 100uF electrolytic audio series pass capacitors, between the DAC chip and the LPF op-amps. They're the large ones that are laying down over the OP275 op-amps.
     
  5. calico88
    what happend if using 220uf or 470uf in this case ?
    what happend to the sq ?
     
    HeyManslowdown97 and DBaldock9 like this.
  6. Ivan TT
    Off the top of my head they are 100uF 10V caps.
    Since there is a 10kOhm resistor to ground on their output they form a HPF, cut-off frequency 0.16Hz
    AK4497 evaluation board has 10uF/20k arrangement (0.8Hz cut-off frequency)
    So based on this I don't believe increasing the value would improve anything sound quality wise.
    Also, I believe 6.3V caps could be used here as AK4497 output is well below that voltage.
     
    Themilkman46290 and DBaldock9 like this.
  7. calico88
    @Ivan TT,
    would you repost your Mod List that has been deleted on page 152 ?
    I just want to try other parts than can bring more detail.

    I can see the "future"
     
    Last edited: Mar 17, 2019
    HeyManslowdown97 and DBaldock9 like this.
  8. Ivan TT
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  9. calico88
    yess, why it's on page 149 ? it was #2276 page 152.
    nevermind, thank you.

    I'm getting parts from arrow and ae ... let the mod and the mood continues
     
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  10. DBaldock9
    While the Thread was locked, several pages worth of off-topic posts were purged.

    Has anyone here experimented with using a pair of cascoded N-Channel JFETS, to provide Class A biasing for your op-amps? - https://tangentsoft.net/audio/opamp-bias.html
    The article refers to 2N5484 / 2N5486 devices, but the TO-92 package style is obsolete now, having been replaced by the SOT-23 package (MMBF5484 / MMBF5486) transistors.
     
  11. Ivan TT
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  12. DBaldock9
    Out of curiosity, what is the size of the footprint for the DAC VREF capacitors (the ones where you used 2x 220uF)?
     
  13. Merlin-PT
    I used 2 in parallel for each side, for a total of 2x220uF = 440uF each side:
    https://www.arrow.com/en/products/t55b227m6r3c0025/vishay

    I measured the PCB pads distance and PCB space before I ordered them, then I searched for a cap size in arrow that could fit the space.
    From the arrow link, this cap measures:
    size (mm): 3.5 X 2.8 X 1.9

    The larger size is 3.5mm, that fits on top of the PCB pads, with only a tiny bit of the PCB pads still showing.
    2.8mm is how tall they will be in the PCB, because they are soldered side way.
    1.9+1.9 =3.8mm is the 2 caps in parallel sandwich size, this size fits without any remaining space left in the PCB.

    I can't measure them now, because they are soldered, but the datasheet has all the details.
    I also found much more expensive options with higher capacity that could fit the space.
    The ones I got had a good price/capacity/size relation, they are "ultra low" ESR and I like the brand.

    The 100uF stock cap that was there measures 3.45 x 2.88 x 1.92 mm.

    The second photo here has a better view of the caps I used:
    https://www.head-fi.org/threads/the-zishan-dsds-corner.826185/page-137#post-14816714
     
    Last edited: Mar 19, 2019
    DBaldock9 and HeyManslowdown97 like this.
  14. PochoLaPantera
    Hi but without mods the sound of the zishan dsd ak4497 is like wich dap? Maybe in the future with more experience i will be dooing the mods!
     
  15. Themilkman46290
    Hard to really say, without mods i would go for ak4495 or even the ak4490 version because they have lower output impedance and go well with everything where the ak4497 really only sounds right with high impedance gear, in stock form i like my ak4490 much better with iems and heaphones like audiotechnica m50x, grado sr80e, or hifiman he4xx. The ak4497 sounds ok with the headphones i mentioned but they get a bit boomy, and distort like crazy if you go above 25-26 out of 31 on the volume, and lose out on sub bass. So if you have high z gear, go for the 4497 or or get it modded to work better with low z gear like some have done, or get the 4495 version that sounds great stock i have heard them all, and i felt 4495 and 4497 are both fantastic. But one thing i can say is if you dont have high z gear and dont want to mod then the 4497 doesnt really make sense, but then again somepeople like b.a. drivers on high z gear, and some love the boomy midbass from low z dynamic drivers on high z sources, and pretty much all heavily marketed gear that you hear about (audiotechnica, sony, fiio, campfire audio, and all iems ) will be low impedance, so a majority of gear will sound different then its supposed to, only high z headphones (beyerdynamic, akg 601,702, sennheiser hd600 and up) and high z earbuds (anything over 100ohms) will work best

    As far as what it sounds similar too, well i also couldnt say, but the ak4490 is better sounding (less digital, better soundstage, seperation, and more dynamic) then the hidizs ap60ii, fiio x1mkii,shanling m1, any ipod, and basically any player in its price bracket
     
    Last edited: Mar 19, 2019
    Merlin-PT, endia and Ivan TT like this.
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