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Jupiter Station High End Media Playback Deck

edited September 2016 in DIY
I've mentioned it in passing before, but since I'm about to build the beast next week on my vacation, I figure I'll detail the design here. Let me start with the overview and then the block diagram of the overall system.

Simply put, the design is simply a costly HTPC focused on audio performance. The core is a Windows PC, driven by a power adapter fed from a laptop power brick. The audio is converted by an audiophile grade AKM4495 dual mode DAC (one DAC per channel to reduce the noise floor). That output is fed into a Burr Brown PGA2311 preamplifier, which is a single chip stereo analog solution controlled digitally. The controller for this will be an Arduino based board, written by me. Here is the block diagram:



The deck requires an annoying three power supply solution. I avoided using a single R-Core for the DAC and Preamp because I'd rather buy the toroids from AnTek.

If you notice, I've chosen to use a splitter to pull the PCM audio from the HDMI feed rather than use a usb connection. This is a choice I made to make the audio experience more transparent, since any device on the HDMI output end will get the same audio feed that the high end output gets, without having to switch any settings in the windows software.

Two additional RCA, line-level inputs all the preamplifier stage to act as a preamp for other attached devices.

The back panel will offer: 2x USB 3.0, 2x USB 2.0, HDMI, Gigabit Ethernet, Wireless N antenna, RCA analog out, 2x RCA analog in. The nice thing about the USB and analog in, means direct level-matched comparisons between USB external DACs can be easily made.

The whole device will be controllable via a 2.4ghz wireless keyboard/mouse, as well as via webpage using local network and devices such as your phone.

The clincher: If I can get the programming for the arduino right, and rig up a simple quality MIC, the preamp stage will be able to automatically level match for DIY events.
= Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
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Comments

  • I'll attach some photos of the PGA2311 and AK4495 boards for viewing pleasure.
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • While the bottom of the boards are not particularly clean, the solder work looks good to me. The caps on the boards are all quality too. I see Vishay, Panasonic, and Chemi-con.I was slightly surprised at the PGA2311 board, as with all the easy connections to hook it up quickly all over, the output is just soldered holes on the board itself. Seems a peculiar choice.The layout of the PCB on the DAC board is very tight around the chip and output stage itself. It also uses minimal bypass capacitors. I see a lot of crazy Chinese dac boards with billions of bypass caps everywhere.

    The input transcoder that feeds the AK4495 is the AK4118, known for being a good low jitter solution. The output stage for each channel is one JRC NE5534 opamp in a minimalist design. I think the board is looking good, can't wait to hear and measure it.
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • edited September 2016
    Jason,

    If you configure the mic input to use a 3.5mm jack and a dynamic microphone, the calibration mics supplied with the better AVR units will work just fine. In fact, I will donate one I have sitting around. Frequency response is not hyper critical when setting levels - since it is applied equally across all DUT. 
    I have a signature.
  • One could also use the iMM-6 by Dayton Audio, in which case I will gladly lend mine for testing purposes. 
    I have a signature.
  • What is the purpose of the HDMI splitter? The audio signal is going from dac to the preamp. How is the audio signal used by the Arduino to control the pre amp?

    Can the mic in be used to control and set the appropriate spl automagically?

    Regards
    Ani
  • JR, that is a good point. I have a Mic like that from my Onkyo in fact.

    Ani, the splitter pulls the pcm audio stream  out of the HDMI output of the PC. The reason for this approach is to make computer operation simple. If you are watching a YouTube video, the same audio stream going to the tv feeding into the DAC.

    There is no audio stream going to the Arduino, it just programs the PGA2311 volume. And yes, with a calibrated Mic on it, we might just have automatic level matching. Which would be awesome.
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • Ok, got it... I thought the red arrow from the splitter was going into the Arduino... and assumed you had some real fancy optimised code on that tiny arduino which was doing bass management, room correction on the pre-amp... oh well, maybe in the next version.
  • Neato, looking forward to watching this build 
    deadhorse - leviathan - harbinger - shockwave (wip)
  • It would be interesting to see how the automatic level matching would work and the resolution that it would have.  Good luck with testing.
  • Jason, where did you get the DAC and preamp?
  • edited September 2016
    I picked them up via ebay. The PGA2311 board is from minishow0328, well known distributor of weiliang dacs on diyaudio.

    The dual DAC was harder to find, but I found this design eventually, with a couple mods that the provider was willing to make for me. Researching it looks like yuan jing designed this board, though it isn't listed on their store.
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • Updates:

    I have all the parts and have started laying out the physical design. It will be two "decks", meaning a two layer design. On the bottom deck/layer will be all the computer components: motherboard, psu, ssd. On the top deck will be all the audio components: DAC board, Preamp Board, Arduino controller, toroids for power. The top deck will have its own power switch, independent of the computer core on the lower deck.

    Here is what I've drawn up for the layout (minus wiring guide) in my trusty draw program:

    Top Deck:

    Bottom Deck:



    The overall box dimensions will be 18" wide, 12" deep, and a little over 5" tall given the two decks. There is some wasted space in the layout but I don't dare push smaller over concern for ventilation and wiring. If you notice there is a hole between the two decks, allowing the CPU cooler for the motherboard to have enough air space to do its job. The top deck will have its own power switch, so that the core can be operated with or without it on as needed.
    greywarden
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • Oh and I've taken care to isolate the power from the signal as much as possible. All the power is located on the right side (top and bottom deck) away from the signal as much as possible. Under the DAC board I'll use copper foil sheeting to enhance separation from SSD and motherboard below.
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • What is the plan for cooling components?
    deadhorse - leviathan - harbinger - shockwave (wip)
  • I don't expect any real heat issues, but the basic plan is a 120mm silent PC fan at the top under a nice grill to draw air into the case. Then some vent slots on the sides of the case on the bottom deck. I feel heat won't be a real issue. It not like any of the non-cpu parts really require serious ventilation, you don't see fans running on dacs for instance :)
    greywarden
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • Recording of the fans in operation:



    Stock Intel Haswell cooler and Antec 120mm True Quiet case fan. All you can hear is me in that video, I couldn't hear them at all from a few inches away. NIce!

    All the machining on the panels for the box was completed today. Pics to come this weekend when I glue up the box.
    greywardenjr@mac
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • Nice, yeah I've done way too much research on cooling fans, and that antec truequiet is at the top of the list.
    deadhorse - leviathan - harbinger - shockwave (wip)
  • edited October 2016
    Lots of work done this weekend, quite close now. Only a few more days and I can test the bad boy out!

    Flickr Album: https://flic.kr/s/aHskEE2L3T

    https://www.flickr.com/photos/jasonp75/albums/72157671272685023
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • edited October 2016
    kennykgreywardenjr@macBryan@MAC
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • Cyclops with a rectangular mouth. You should name it Cyclops.
    ............. could you hum a few bars.
  • Looking great Jaason!
  • "Balcony" for the audio pcbs and toroids installed, now just the top and some serious sanding tomorrow and I can assemble.

    https://www.flickr.com/photos/jasonp75/29511733123
    greywardenjhollanderNicholas_23
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • Badass man.  Love it.
    My signature goes here
  • edited October 2016
    https://www.flickr.com/photos/jasonp75/30139497256

    Assembled with the top on.

    Now to get it all together, tested and in working order. The fancy cutout on top is for the 120mm silent fan to cool the components. Air flow exits from the small quarter-inch holes on the sides.

    I hope to have the start of the distressed metal finish on the birch ply before Iowa!
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • For easy of access, upgrades, or just showing off the internals at events I am using magnets to snap the top on.

    https://www.flickr.com/photos/jasonp75/29545225874
    greywardenNicholas_23kennyk
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • Cool.  A removable, transparent grill cloth for electronic gear.  Can't wait to see, photograph, and hear this thing next week!
  • greywarden
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • greywarden
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • greywardenani_101
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
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