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Grant Fidelity TubeDAC-11 capacitors

Discussion in 'DACs' started by mroboto, Sep 2, 2016.

  1. mroboto

    mroboto Super Member

    Messages:
    1,462
    Hello,

    Own it for a few years and want to upgrade some capacitors for Elna SILMIC II and make some decouping with CBB 2.2uf 250V for High Voltage 100V capacitors and ceramic maybe 0.1 , 2.2uf , 4.7uf and 10uf 50V for some of the 35V and 16V electrolytics, if the decoupling caps can fit under the board, approx ΒΌ" of an inch.

    One of the first thing that comes to my mind is to replace the solid capacitor for an audio capacitor for the analog power of the Cirrus Logic DAC chip that seems to be the pin #6 close to the dot, and seems to be connected at the left to a solid capacitor that have no black mark on top for negative side, so, have a question, is this a polar or maybe non polar 22uf 16V solid capacitor around the DAC chip 2nd from top in the middle of the board ?

    If you own it and/or know this circuit, some ideas comes to mind, please share.

    For picture, you can clic on FIcsQeEfIDq_TubeDAC-11.JPG at the right of "Document joint:" to enlarge and download.

    On this link: http://www.cjoint.com/c/FIcsQeEfIDq

    Thank you and have a nice day.
     
    Last edited: Sep 2, 2016

     

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  2. SoNic67

    SoNic67 Well-Known Member

    Messages:
    919
    You can download the datasheet for the CS4398 and check the capacitor requirements:
    https://www.cirrus.com/jp/pubs/proDatasheet/CS4398_F1.pdf
    Pin#6 is MCLK so no capacitor there.
    Pin#7 is VD (digital +5V) and pin#8 is GND, so maybe that is what you see. VA (analog +5V) is on the other side of the chip.

    The main thing that drags down that DAC is the Tenor TE7022 USB receiver.
     
  3. mroboto

    mroboto Super Member

    Messages:
    1,462
    I see and have the Datasheet of CS8416

    I use SPDIF , not USB.

    I found the mids and highs a little bit accentuated with most good tubes.
     
  4. mroboto

    mroboto Super Member

    Messages:
    1,462
    Ok, i found the CS4398

    So, what i was loking to another chip than the DAC, the big chip.

    Thanks.
     
    Last edited: Sep 3, 2016
  5. SoNic67

    SoNic67 Well-Known Member

    Messages:
    919
    CS8416 is the SPDIF receiver chip, not the DAC.
     
  6. mroboto

    mroboto Super Member

    Messages:
    1,462
    Yes, you set me on the right way, thanks.

    I think i am better to not mess with solid capacitors.

    I will replace the three no name 470uf 16V chinese capacitors and decoupling some capacitors i will be able to.

    I think that i see output coupling caps , 47uf 63V , that seems by the logo to be Nipon Chemicon, don't know to witch output they leads, will check this and replace them as well.

    Don't know if it's worth to replace the Rubycon 2200uf 35V for Elna Silmic (first gen.) , the standard Nichicon 470uf 100V for Nichicon Muse Fine gold, things that maybe i will try sooner or later.

    There is 2 red Elna Cerafine 47uf 16V for opamps (i think), that is one of the best, not sure if Silmic II can suits my tastes vs Cerafine.
     

     

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  7. SoNic67

    SoNic67 Well-Known Member

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    919
    OpAmps... those probably can be upgraded too?
    I am using ChipQuik for desoldering SMD's.
     
  8. mroboto

    mroboto Super Member

    Messages:
    1,462
    I am not knowledgeable in opamps technologies, Here's what i see: http://www.cjoint.com/c/FIemCXpQ4pq

    But it's too much sensitive for me, i don't want to take risks and scrap this unit.

    I ordered some caps, will hope and try .
     
  9. SoNic67

    SoNic67 Well-Known Member

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    919
  10. mroboto

    mroboto Super Member

    Messages:
    1,462
    Since yesterday, i use the Optical input with a 15' TosLink cable, and it seems to be a little bit better, cleaner, maybe less jitter or noise from the computerthan 15' SPDIF cable.
     
    Last edited: Sep 6, 2016
  11. mroboto

    mroboto Super Member

    Messages:
    1,462
    The 470uf 16V Elna Silmic II capacitors i received are twice as tall as the purple chinese no name (bizare code instead), like some of the capacitors i got with my Yaqin MS-300C, (replaced with F&T caps for this one).

    But they will fit.
     

     

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  12. SoNic67

    SoNic67 Well-Known Member

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    919
    The silk based separator layer is much thicker than the standard one, so all the Silmic caps will be bigger at the same capacity.
     
  13. mroboto

    mroboto Super Member

    Messages:
    1,462
    I have received almost everything and they will fit, in one way or another.

    The only thing that will not fit unless i run wires and use space in the left corner and glue the capacitors, are the Nichicon Fine Gold 470uf 100V

    I will also have much more space to bypass them with CBB 2.2uf 250V as i hope to be able to do.

    The 470uf 16V Elna Silmic II will probably be a good upgrade move.

    Will bypass the 2200uf 35V Elna Silmic with 50V monllytic ceramic capacitors, i have 10uf , 4.7uf , 2.2uf in stock, I think i will go for the 10uf, they are very small and will fit under the board.

    For the opamps Elna cerafine, maybe good old 0.1uf ceramic disc.

    Not sure when decoupling will be overkill, but at the low cost of these little capacitors...
     
  14. mroboto

    mroboto Super Member

    Messages:
    1,462
    Work have been done today, it sound beter, happy with results..

    http://www.cjoint.com/c/FJhaUDkGQqB

    I bypassed only the three 2200uf 35V with 10uf 50V and the two 470uf 100V with 2.2uf 250V as i previously tell you.

    Replaced the standsrd Nichicon for Nichicon Fine Gold, all 3 Rubycon for Elna Silmic, chinese 470uf 16V for Elna silmic II, as well as two others 47uf 63V in the back for Silmic II.
     
    Last edited: Oct 6, 2016
  15. rogerfederer

    rogerfederer AK Subscriber Subscriber

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  16. SoNic67

    SoNic67 Well-Known Member

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    Do you have other bypass caps on the back of the board? Because those long leads have an inductance that basically will cancel any benefits form the bypass caps located at their end (high frequency components will never reach those caps).
     

     

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  17. mroboto

    mroboto Super Member

    Messages:
    1,462
    Under the board i only added 10uf 50V Monolithic Multilayer Ceramic Capacitors to 2200uf 35V new Elna Silmic.

    There were no other bypass cap.

    The two big 2.2uf 250V CBB are too thick to fit under the board, and new Nichicon Fine Gold don't fit between the board and cover, missing a few millimeters, at least i found the needed space.

    I thinked about to put the bypass caps in the holes and joint only the electrolytics by the long leads, but i don't want high frequencies to be more sensitive or closer than the rest of signal spectrum, so i put everything far.

    This is copper, not steel, maybe i should find pure silver for best results.

    Result is soft in the higs and more articulated in the bass and mid bass, at least, i can tell it's beter now.
     
    Last edited: Oct 7, 2016
  18. mroboto

    mroboto Super Member

    Messages:
    1,462
    Adding another bypass cap of smaller value, closer, at the base of the lead on the board could be an interesting idea.
     
  19. SoNic67

    SoNic67 Well-Known Member

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  20. mroboto

    mroboto Super Member

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    Last edited: Oct 8, 2016

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