Ec-Designs Multi-Bit DAC

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by murphythecat, Dec 2, 2018.

  1. purr1n

    purr1n Desire for betterer is endless.

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    It looks like the DAC does have a shutdown mechanism before the 3.7V battery drops below a certain level. 24 hours of charging yields a 2.9V charge, which is insufficient. This battery completely charged should read 4V+ on a DMM.

    Attached is a photo. @murphythecat: I'd like to investigate looking into replacing the battery. The part number is there. (Anyone feel free to look it up). Actually, any other battery with similar spec will do. Preferably Japanese rather than Chinese manufacture.

    FYI, the battery was jarred loose during shipping, I actually put it back into place under the wire ties. Shock can kill these batteries.

    IMG_20190214_104821.jpg
     
    Last edited: Feb 14, 2019
  2. bilboda

    bilboda Florida boomer

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  3. purr1n

    purr1n Desire for betterer is endless.

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    TY. With permission from @murphythecat, I can purchase and install. Worth the extra effort as I like what I am hearing. With a full charge, it might sound even better.
     
  4. Scott Kramer

    Scott Kramer Friend

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    Is that an ak4113, dir9001 or wm8805 spdif input chip, and 74hc595 shift registers everywhere? Looks hand soldered.
     
    Last edited: Feb 15, 2019
  5. JustAnotherRando

    JustAnotherRando My other bike is a Ferrari

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    It's hard to tell on a phone screen, are there two bare copper wires running from the top capacitor across the width of the board?

    Edit: A couple more battery options, from within CA. Both are a bit longer, but look like they should fit. I used to use Batteryspace when I messed around with DIY lighting, and before shipping lithiums became a pain.

    https://www.batteryspace.com/custom-polymer-li-ion-battery-3-7v-1800mah-6-7wh-2a-rate.aspx
    https://www.batteryspace.com/polymer-li-ion-battery-pack-3-7v-1500mah-5-55wh-2-0a-rate.aspx
     
    Last edited: Feb 14, 2019
  6. mscott58

    mscott58 Friend

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    And 5% off with coupon E7SEA!
     
  7. purr1n

    purr1n Desire for betterer is endless.

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    Looks like this unit was tweaked with extra ground connections. Some of that stuff shouldn't be there. :rolleyes:

    The battery (-) was lifted from the plug and directly wired to a cap up at the top of the board. I'm restoring the battery connection so it charges properly. No, @murphythecat was not responsible for the tweaks.
     
  8. bilboda

    bilboda Florida boomer

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    I saw that and assumed it was a normal part of the circuit. You sure this connection is not necessary to complete the circuit in the amp ?
     
  9. purr1n

    purr1n Desire for betterer is endless.

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    There is stuff that I don't think should be there. At first, I thought the designer of the DAC was nuts, a solid engineer, but also a crazy audiophile DIY'er (we audiophiles tend to do nutty stuff like that right?) that couldn't resist adding random wires and possibly creating ground loops all over the place. But it turns out this is not the case.

    I'm still afraid to cut the bare wires at the left because I don't know if the modder cut the traces on the board and is relying on those copper wires. I don't like the bare wires there at all. Shipping, movement, etc. can cause an accidental short.

    I restored the black (-) cut wire on the connector with a green wire. I'm kind of curious what the direct ground connection to the cap up top would do to the sound (if anything), so I didn't make the final solder connection to the battery yet. I put a twist-on wire connector on the (-) leg in the meantime for an easy switcheroo. It's charging properly now. Monitoring for smoke and explosions.

    IMG_20190215_094010.jpg
     
  10. purr1n

    purr1n Desire for betterer is endless.

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    BTW, I'm geeked. Can't wait until I hear this thing on a proper charge. FWIW, a prototype of the MD x Airist RDAC board running on a battery (not a switcher) sounded fantastic: better than Gungnir A1 in terms of microdynamics, but not as good in microdetail or soundstage.
     
  11. murphythecat

    murphythecat GRU-powered uniformed trumpkin

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    yay or nay?
     
  12. purr1n

    purr1n Desire for betterer is endless.

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    Yay. Very much so. I'll move it to the more resolving (but screwier FR) OB/horn set up. Then off to @Hands?
     
  13. murphythecat

    murphythecat GRU-powered uniformed trumpkin

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    no rush! take your time to evaluate it!
     
  14. JayNYC

    JayNYC Friend

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    @murphythecat do you also have either of ECDesigns USB stick transport products (UPL16/UPL24)? In many ways, ECDesigns transports may be more 'profound' than their DACs. Would you be willing to send your transport to the 'Major Players' here for evaluation? I feel like a uniquely designed and optimized USB stick transport is special and more sufficiently differentiated than a sea of (Multibit) DACs.
     
  15. purr1n

    purr1n Desire for betterer is endless.

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    He already offered. I might not have the time and also because it presents a poor use case for me.

    Might be interesting to compare built-in stick source to good CD transports. The thing is, MOS makes it difficult to make a meaningful comparison. Toslink sounds like ass compared to SPDIF coax from the good CD transports.

    The whole galvanic isolation thing behind Toslink is nonsense because of the following: 1) It was always sounded worse than coax from a given CD transport; 2) AES3 or what is balanced SPDIF can provide galvanic isolation through the use of transformers.
     
    Last edited: Feb 21, 2019
  16. murphythecat

    murphythecat GRU-powered uniformed trumpkin

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    im in no rush, if you like I can send you the UTOS from ec designs so you can evaluate the entire chain as intended.

    edit: im awfully tempted to order the UPL16 and ship it out to you!
     
  17. lehmanhill

    lehmanhill Almost "Made"

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    @purr1n,
    Did you notice any warm up issues (ala Schiit and others)? I was curious about the limited play time of battery power combined with a desire to have everything warmed up for best sound. Or did the new battery/connection issue completely resolve the listening time problem?



    Just a few years ago you couldn't make that statement regarding multibit dacs. Interesting how much has changed.
     
  18. purr1n

    purr1n Desire for betterer is endless.

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    It seems good to go rather quickly after I got the battery issue sorted out.

    I will be buying a few pots with a switch for a level matched blind test of several DACs with this one.
     
  19. lehmanhill

    lehmanhill Almost "Made"

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    It seems like a pretty easy mod to change over from Toslink to coax SPDIF. In the pictures, it looks like a typical Toshiba Toslink receiver with accessible traces. I'm not suggesting that you mod Murphythecat's MOS 16, but it seem like the owner of a MOS 16 could remove the Toslink receiver, mount an isolated RCA connector to the chassis, and connect the RCA to the data and ground traces.

    One risk would be the dac having been voiced around the Toslink sound.
     
  20. soekris

    soekris MOT - Soekris Engineering

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    It's not that simple, a Toslink receiver outputs digital ttl signal level, while SPDIF Coax is a 0.5V pp analog signal....
    Anyway, a good Toslink implementation is as good as SPDIF Coax.... There may just not be that many good Toslink implementations....
     

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