Audio-GD DAC19mk3 + BNC and RCA mods = damn, this is actually pretty nice!

Discussion in 'DIY' started by ohshitgorillas, Jun 28, 2020.

  1. ohshitgorillas

    ohshitgorillas Friend

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    I got this DAC used for around $325, I think? and while I certainly liked a lot about it, it never could compete with my last gen Bifrost Multibit. In particular, I was a fan of the rich, thick, and intimate sound, but ultimately it just sounded a little soft for my tastes and was noticably less clear than the Bifrost. Second, the seller never mentioned that the DAC was limited to 48 kHz sampling rates, which kinda irked me because some of my favorite albums happen to be in 96 kHz. I decided I was just going to sell it on, after upping the resell value with a small amount of effort: the output jacks were cheap, the bare wires connecting the two jacks had rusted over, and for the coaxial S/PDIF input, they used two random wires instead of 75 ohm coaxial cable. While most people get USB nervosa, but I actually get coaxial nervosa, mostly due to the widespread use of RCA connectors for SPDIF on anything but DACs that are mostly out of my price range.

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    The process was really easy. For the coaxial input, I installed a Canare 75 ohm BNC connector, and wired it to the PCB using some 75 ohm silver-plated copper coax wire. I used low-mass KLEI Copper Harmony RCA jacks for the outputs, wired to the circuit board with a combination of Duelund's silver in oil and silk, and Jupiter's cryogenic 6N OCC copper in cotton. I used both because I couldn't decide which would be a better complement, and because the two wires were mechanically much stronger than just the one. I thought about replacing the IEC inlet with Furutech, but that would have required significantly more disassembly, and I wanted to keep this simple.
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    I've been meaning to get some photos of the insides now that the whole job is finished and the unit is cleaned up, but I also don't want to turn it off. My phone's camera loves focusing on dust rather than whatever is right in front of it.

    The results are actually really impressive. I currently have both the DAC-19 and Bifrost Multibit hooked up to the Saga so I can switch back and forth. Both are being fed with the Pi2AES via BNC (1 BNC output and 1 AES > BNC trafo). By far the most obvious difference is in the bass, where the DAC-19 has better definition, heft, and slam; bass guitars sound more real with a more pronounced attack. Other differences aren't night and day, but the DAC-19 now sounds more well defined and focused, with better resolve, textural detail, body/presence, placement, and separation... these add up to a sound that, to me, is more believable and realistic, and that makes for a way better and more enjoyable listening session. I've never heard my speaker system reproduce this level of textural detail and definition, and it's proven to be very lovely and addictive. I did these mods to fetch a higher sale price, but fuckin' a, this is a keeper.
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    Yes, it's still a super warm, thick, tubey sounding DAC, but it's at least now it's a reasonably detailed, textured, and well defined type of warm, thick, tubey sound.

    Yeah, the sampling rate thing is annoying, but in the end it's a small trade-off for such an improvement. In my experience, the amount of focus lost to down/upsampling is tiny relative to what's lost by the use of RCA vs BNC for coaxial S/PDIF. Also, this DAC which is supposedly limited to 48kHz has no issues playing 88.2kHz files? I'm still wondering if there's a way to get moOde to play around with different filters, or to set rules, e.g. 44.1kHz files play bit perfect but 96kHz is automatically downsampled to 48. Maybe that's something the Gentoo player OS could do? For the time being, I'm not too worried about it.
     
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  2. fastfwd

    fastfwd Friend

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    I'd be surprised if that's true -- as far as I know, the PMD100 is limited to 48 KHz plus a little bit.
     
  3. ohshitgorillas

    ohshitgorillas Friend

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    I don't blame your skepticism and have no explanation, but I do have at least a few albums at 88.2 kHz and it plays them directly with no issues whatsoever. I even forced the output sampling rate of the Pi2AES to 24 bit / 88.2 kHz and played back several albums at different sampling rates. The only issue I had was some weird, quiet static during very quiet passages from downsampled 96kHz files.
     
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  4. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Some of the older Audio GD stuff can be pretty decent. I have one of their older, low-cost, Wolfson DACs, and there are some things it does very well.

    You could always consider looking for a DF1704 based SRC, or even use a combo AK4118 and AK4137 SPDIF/SRC board if you can identify power output pins and I2S pins.

    But the PMD100 should have some unique, desirable traits that make it worth the redbook sampling rate limitation.
     
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  5. YMO

    YMO it's not drinking alone if you're on Zoom

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    Agreed. I had their Compass2 Fun DAC/Amp with Dual WM8741s, very good for the price at the time. I used that on some local meets and people prefer that box over various $2k+ DACs at the time.
     
  6. ohshitgorillas

    ohshitgorillas Friend

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    Yeah, I actually emailed with Kingwa about this when I got the DAC and discovered that it definitely can't do 96 kHz files. I gave it some thought but in the end I decided it wouldn't be worth the trouble since I wasn't going to keep it. Now that I am planning on keeping it, I'm content just to run with the PMD100 since I actually do like the sound.

    An I2S input board, on the other hand... that is seriously tempting. But I do not have the casework skills to carve an HDMI port in the back panel.

    Edit: Emailed Kingwa about the I2S input anyway. If half of the praise I've read about I2S is true, it's worth a shot at least.
     
    Last edited: Jun 29, 2020

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