A tale of 3 digital transports (shootout with Unison USB and AES)

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by rlow, Jan 11, 2020.

  1. MisterRogers

    MisterRogers Ethernet Nervosa

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    Ha! File that under 'lies our wives tell us old farts!'. Great discussion / thread; thanks for all the time you're putting in on this @rlow - much appreciated.

    As one given to nervosa of all flavors (USB, Ethernet, etc.), and exotic PS overkill - I'll circle back here later (when I'm not at work) and share some of my experiences (read 'hard lessons learned') on power supplies.
     
  2. bixby

    bixby Friend

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    Very informative thread! :punk:

    I have heard my win based old desktop next to Allo USB Bridge with 2 ifi power supplies. Roon endpoint run on both from core roon server downstairs on pc via ethernet. Yup, Allo nudged out ahead of "me ole desktop" as expected but not by a big margin.

    This brings forth a question about a non-Roon setup with Pi or another computer that can run a player with a local ssd based library of files. Any experience and/or thoughts on alternate HW & Players with a simple Linux OS that is rather straightforward?

    Either with attached storage or shared storage on a drive hooked up to a win pc?
     
  3. rlow

    rlow A happy woofer

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    Yep it was the AES. I put the input/output used in parenthesis after the device in the title before each compare. Don’t have a BNC cable, but I assumed AES would be the best next to i2s.
    As much as the power supply thing can go way into nervosa-land (as some of the funny/sarcastic comments on the previous page highlight) we all know that power supplies matter in just about everything. However, the amount and type of improvement from a better supply is device dependant no-doubt. And you need to consider the cost of some of these supplies relative to the cost of the transport - the ratio needs to make sense, otherwise you may just want to move up to a device that does a better job with a cheaper (or included) supply.

    The one good thing about a good seperate power supply though is that they can be potentially be reused for another transport in the future, assuming they meet the voltage/amperage requirements.

    That’s one thing that kind of annoys me however about the Sbooster and some other power supplies is that they don’t support more than 1-3 voltages for a particular supply. Is it that hard, or more expensive, to provide a wide range of voltage options in a single unit to make it more flexible in the future? Is It kind of a cash grab to have a bunch of SKUs that only differ by voltage? I can understand this with the cheaper switchers, but why can’t a premium LPS support anywhere from say 5V to 24V?
     
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  4. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    The output voltage supported by a linear power supply is almost always determined by the main transformer that converts the AC input 110 or 220 V to lower AC voltage that is a bit above the desired output. This is then regulated with a linear device which must absorb the extra voltage times the desired output current as heat. As such it is not very practical to have an output voltage range of more than a couple of volts unless you use a more expensive transformer that offers multiple taps.

    Michael
     
  5. rlow

    rlow A happy woofer

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    Figured that was probably the case, thanks Michael!
    How much more expensive are we talking
    about relative to a single tap transformer? And would that multiply some of the other parts as well?
     
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  6. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    I am afraid I can’t really answer that for sure. The Transformers themselves are probably double the cost, and then you need some adjustability or the ability to switch the values in the linear regulator section to be able to pick different voltages. Conceptually quite simple, but in practice it could be more challenging. Especially because the whole purpose of this is to achieve very low noise.

    I think the only way is to research linear power supplies and see who offers adjustable or selectable voltage outputs.

    Michael
     
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  7. drgumbybrain

    drgumbybrain Science Nut

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    Someone had any experience with metrum ambre? How about the sound quality vs those options @rlow described?
     
  8. msommers

    msommers High on Epipens

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    Apparently Ambre is slightly better, but that was also AES vs I2S iirc and the two in the same format haven't been directly compared. @MisterRogers ?
     
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  9. MisterRogers

    MisterRogers Ethernet Nervosa

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    Ambre vs. PI2AES (powered via an Illuminate v3), both I2S... either is better depending on the rest of the chain and my mood. Both are extremely high performing. Ambre is currently in my main chain, feeding Morpheus, which is feeding both 3F and SW51+. I have an EtherREGEN (pure, un-fettered Nervosa) upstream from Ambre. chain is stupidly good and is scratching the itch this week. I could swap in PI2AES and the sonic character would be different; better in some ways worse in others, but still very good.

    While I'm feeding PI2AES with an expensive PS, the sonic drop-off with the supplied switcher isn't that huge, making PI2AES one hell of a value.
     
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  10. earnmyturns

    earnmyturns Smartest friend

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    At work, I use a Pi 3 running moOde with a Pi2AES, a PiTouch screen, and a 2TB USB SSD (ext4 format) feeding AES to a Soekris dac1541 and downstream components. The Pi 3 and Pi2AES are powered by the Meanwell SMPS that Pi 2 Designs sells, the PiTouch screen by a random USB power wart I had around. It all works very well. I bring the SSD home periodically to update it from my master FLAC repository.
     
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  11. Raicorl

    Raicorl Acquaintance

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    Which OS do you use for both Ambre and PI2AES?

    off-topic : Is EtherREGEN worth it? (price wise) Asking for a friend..:p
     
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  12. skem

    skem Friend

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    I own two Allo DigiOnes, which I used for my DAC shootout (which incidentally compares Eitr to DigiOne for those interested. One DigiOne is powered by good Li-Ion cells. The other by ifi wall warts. I could not hear any difference between these power supplies.

    This remained true with my steady-state DAC choice (Adagio) even after replacing the XA30.8 with the more resolving XA25. I would like to try with CS Solaris, as it was the only DAC I tried that was even more resolving (and more responsive to) source choice than Adagio. But overall, Adagio is a pretty responsive DAC, and that leads me to believe that I’m at the limit of what DigiOne can do.

    Although batteries are cleaner DC under constant current applications, they do have a small source impedance, so spikes in current demand can cause small voltage dips. I don’t know if Hands was operating anywhere near the regime where this matters, but this is a possible reason why batteries might not always sound better.
     
    Last edited: Jan 19, 2020
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  13. MellowVelo

    MellowVelo Friend

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    Has anybody compared a Pi2aes to a Lynx soundcard, like the E22? I’m currently using a MacBook Pro connected via Thunderbolt to a Lynx E22, which then connects to Yggdrasil via AES. It sounds great, but I would love to set up a Raspberry Pi and a Pi2aes in order to go totally wireless in my system. Does anybody have experience comparing these or similar setups? Thanks.
     
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  14. MisterRogers

    MisterRogers Ethernet Nervosa

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    I'm glad you framed your question subjectively :) Yea, to me it's worth it. The CO crew will get a chance to weigh in at our meet as to whether they hear a difference and it's a positive one, but in chain I notice a lower noise floor, tighter bass, and more analog presentation (I read that as more accuracy or stability in the time domain).

    But what do I know - I'm given to Nervosa.
     
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  15. Raicorl

    Raicorl Acquaintance

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    No worries, Im also down to this road tinkering around what I have.(no more $$$ buy). PI2AES and Digione are enough to keep me busy with power/software swap for fun. Then I saw discussions around CISCO 2960 switch, with a used price at 25USD I was like "why not?" and I could hear a difference..

    Keeping audio chain (also network) simple still hold true to my believe but yep. I just need a 'better' one.. :D
     
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  16. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    I don't activley discourage two power supplies. I understand the desire (obsession/addiction/pathological need?) to improve and tweak and would never think poorly on it. As a commercial product with cost/performance trade-offs we did what we could to immunize the PI2AES from external power supply noise. There is always some room for improvement, but as @rlow said, there are many links in the chain that would gain you more bang for your buck.

    Cheers,
    Michael

    P.S. Sorry @msommers , you praised my participation and then I missed posting this reply for way too long!
     
  17. JonnieD

    JonnieD Acquaintance

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    Useful thread!

    I'd like to hear the differences between my Pi2AES vs the SMS-200 when Unison is available for my Yggdrasil.

    But in the meantime, did anyone else try lead acid batteries to power their Pi2AES?

    I've got two large 12v batteries in series sitting in my office (speaker based) system. And listening using those vs. the Mean Well supply gives me some of the improvements @rlow reports for the SoTM over the Pi2AES. There's really a useful level of improvement to my ears.

    Whilst I've got the slightly more powerful Mean Well power supply, according to the manufacturer mine does have a lower level of noise vs. the one that Pi 2 Design sells. I'm guessing the improvements I hear are from the very low noise levels from the batteries, and also the unlimited current available with those (>100 amps!).
     
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