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  1. #1

    Lightbulb Improving Google Chromecast Audio Sound Quality

    Okay, I have been using the Google Chromecast Audio (heretofore CCA) for quite a while now. Mostly with the Tidal app via iOS, but also with the Neutron app streaming lossless FLAC files from my NAS (44.1/16 to 96/24). Streaming the exact same FLAC files from my old Panasonic DMP500 BD player yields fantastic results. However, grit/grain, reduced depth and width of sound stage, and a reduced sense of air was always present when switching to the Google CCA. Even when both were using optical toslink (the Panny is typically used with a coaxial S/PDIF connection) into my Arcam AVR300 (which I use as a pre/pro). The std Google CCA power supply adapter was plugged into my Belkin PF30 Power conditioner (as was the improved adapter below).

    Same basic lack of enjoyment via Tidal. This is as compared to using the Tidal desktop app into my FPGA based RME Babyface Pro USB DAC into my Blue Sky Designs Sat6D studio monitors in my lab/studio at work. Same negative traits on a totally different setup listening to the same titles.

    So, I experimented with a better quality AC->USB power adapter, USB micro cable, etc.

    I switched to a spare current-gen Apple iPhone std wall cube charger, Anker Powercore/Powerline micro USB cable, and a ferrite choke located approximately 2.5" from the Google CCA on the cable (a 3mm choke IIRC).

    Now, I haven't placed this setup or the first one on an oscilloscope, so if you're looking for lab analysis, you can shop elsewhere. I'm going to relay my educated, expert listening opinions as a Forensic audio engineer and that's all you're going to get. I'm not interested in objectivist absoluteism. I am friends with far too many professional musicians (defined as people who receive money to perform and this is their primary source of income) to have some person I've never met tell me what I am or am not hearing. I get paid to help judges and juries do that. So spare me, please, if that's your bent.

    Onto listening impressions:

    I noticed an immediate improvement in the form of a reduction of grit/grain, less of that high frequency glare, and a slightly widened and deepened sound stage. And when I say immediately, I mean that in the most literal sense of the word. The difference was striking. So I put all the the usual albums on to test (Holst The Planets via Dutoit in Montreal, Trio Pim Jacobs, etc), and the improvements held. Then onto some high bitrate lossless from my NAS and, again, the same improvements were experienced.

    So, between an Apple iPhone std charger cube, Anker Powercore/Powerline micro USB cable, and a strategically placed ferrite choke, I basically fixed the huge issue that sapped my pleasure from the CCA.

    You're not going to get a better front end for TIDAL for $35. And with some cheap "mods", it actually sounds decent.
    Last edited by BufordTJustice; 05-06-2018 at 09:27 AM.

  2. #2

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    Quote Originally Posted by BufordTJustice View Post
    I noticed an immediate improvement in the form of a reduction of grit/grain, less of that high frequency glare, and a slightly widened and deepened sound stage. And when I say immediately, I mean that in the midst literal sense of the word. The difference was striking. So I put all the they've albums on to test (Holst The Planets via Dutoit in Montreal, Trio Pim Jacobs, etc), and the improvements held. Then onto some high bitrate lossless from my NAS and, again, the same improvements were experienced.
    Great story, BTJ. You've confirmed some fundamentals:

    1. Assume everything has a sound because everything shall. Whether X is humanly audible to Y is what varies.
    2. Assuming good parts and design, good sound depends largely on what we take out.
    3. Outcomes really shouldn't be predicated on preconceptions.

    Hifi isn't an abstract and it's not perfectable; it's humanistic. Plug some stuff in and give it a whirl...
    J. Lane

  3. #3

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    I've been using the Google Chromecast HD and suspected there were shortcomings. I use an android phone and always opt for highest Google music quality setting but not sure what the file format is. I wish there were better wireless options. Maybe I need to use the USB for optimal sound?

  4. #4

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    Quote Originally Posted by Chane M&C View Post
    Great story, BTJ. You've confirmed some fundamentals:

    1. Assume everything has a sound because everything shall. Whether X is humanly audible to Y is what varies.
    2. Assuming good parts and design, good sound depends largely on what we take out.
    3. Outcomes really shouldn't be predicated on preconceptions.

    Hifi isn't an abstract and it's not perfectable; it's humanistic. Plug some stuff in and give it a whirl...
    So true, Jon!

    Also, a well researched little piece on the quality of electricity as sent by several USB power supplies. The enormous breadth of performance (from outstanding to it-might-break-something) shocked me. Pun fully intended.

    http://www.righto.com/2012/10/a-doze...le-is.html?m=1

  5. #5

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    Quote Originally Posted by kabin View Post
    I've been using the Google Chromecast HD and suspected there were shortcomings. I use an android phone and always opt for highest Google music quality setting but not sure what the file format is. I wish there were better wireless options. Maybe I need to use the USB for optimal sound?
    The Chromecast AUDIO is a little different than the std Chromecast. Same internal processor, but it has no visual interface outside of the Google Home iOS and Android app.

    Still, providing better quality power to the device simply cannot ever hurt performance. And, in this case, the price of admission is so low there's basically no downside.

  6. #6

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    A full tear down and analysis of the previous generation std iPhone cube charger from Apple. For a Google CCA that only draws 200ma, it may be the perfect supply at any reasonable price point.

    http://www.righto.com/2012/05/apple-...ality.html?m=1

    And I really need to give kudos to Ken Sheriffs blog. Dude is an over achiever.

  7. #7

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    Quote Originally Posted by kabin View Post
    Maybe I need to use the USB for optimal sound?
    Quote Originally Posted by BufordTJustice View Post
    ...providing better quality power to the device simply cannot ever hurt performance.
    What's happening here apparently isn't related - or isn't completely related - to the digital bitstream. The audible artifacts come from switching noise on the power supply, whether inbound to the DUT or reflected to other components back down the supply rail.

    In other words, dirty power from cheap supplies is highly audible. It seems counter-intuitive until you realize that an audio amplifier is just a valve on a power supply and the supply is the driver for the load. Therefore noise in the supply will contaminate the signal. And the cheaper the supply the more audible the effect.

    Those oscilloscope captures at BJT's link are very, very telling.

    Lynn Olson writes about this on his Nutshell HiFi, and how what BTJ calls "absolutist objectivists" have missed its mechanism. In a sense there is no "properly designed amplifier" category to lump amps into so as to assume they will sound good.

    Mainstream AES-school engineers have ridiculed "audiophile" power cords for many years, but EMI emission from solid-state-rectifier power supplies is no joke. It's hard to identify on a scope (the trace just looks a little thicker), but a wideband spectrum analyzer clearly displays the comb spectra created by the switching devices. The fancy power cords may be doing their greatest benefit by partially shielding the dirty power supplies from other solid-state equipment and CD players.


    Of course, this begs the question: why tolerate dirty supplies at all? The broadband noise is radiated in all directions: into the circuit boards, the grounds, inside the chassis, and out the power cord. If any partly-filtered digital residue is floating around (and this is inevitable in even the costliest DAC's and CD players), the power supply noise will cross-modulate with digital residue as soon as the first nonlinear circuit element is encountered. How linear are most op-amps at 1 MHz? Not very. That's video-amp territory, not audio.


    Every time you see a transformer, solid-state bridge, and input cap, you have a noise problem.
    I've spent years looking at amplifier circuits and while that's all beyond this scope, the lengths you can go to to make a "proper" audio power supply are remarkable. Completely innocuous audio power supplies, if any even exist, are as expensive as they are rare.

    Run your sources from the best power you can. In the case of these tiny low current sources, even consider large batteries. The odds are if your system has enough resolution you'll hear just what BTJ is experimenting. Watch out because it's a rabbit hole...
    J. Lane

  8. #8

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    Here's a picture of what I've done. If you place the ferrite choke too close to the CCA, you'll interfere with its WiFi antennas. This is about right and no negative effect on WiFi.

    Can't say how much I'm actually enjoying this thing now.


    15945567-0DC5-4040-A28E-BA19D0E1C736.jpg
    Last edited by BufordTJustice; 06-01-2018 at 10:01 PM.

  9. #9

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    I realize this thread is somewhat old.

    Interesting observations nonetheless. I recently bought Chromecast Audio, so I thought I'd try changing to a known quality power adapter and USB cable with ferrite choke on the cable. Alas, I can't say that I hear any difference when streaming FLAC files to my receiver via optical cable. Granted, my ears may not be too discerning.

    FYI, the Google supplied USB adapter can deliver up to about 1A of current, alas, I don't know how cleanly it delivers it. The CCA only draws about 0.2A. In my normal setup, I use a USB port on my receiver to power the CCA.

    The Google supplied USB cable does have a lot of internal resistance though - about 350 mOhm. My nice (and short) USB cable is under 100 mOhm. Again, at such low current, it shouldn't matter a whole lot, but who knows...
    Last edited by e-2-m; 01-07-2019 at 04:40 PM.


 

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