Computer Audio Asylum

• We do requests: How to use iFi units for USB Audio - Thorsten 06:32:13 02/23/14 (0)
  In Reply to: RE: How to get the best out of a USB Dac? posted by racerxnet on February 22, 2014 at 11:52:48

  Hi,
  
  > wondering if Thorsten could chime in here regarding his products
  
  Okay, first I would suggest looking at the iFi-audio.com Website:
  
  http://ifi-audio.com/en/improve.html
  
  This gives general context and connections etc.
  
  You may also find the various notes we posted on Facebook useful, they go into more detail on features etc.:
  
  http://www.facebook.com/iFiAudio/notes
  
  You need to be on Facebook to access them. You could e-mail info at ifi audio for copies if you cannot access Facebook.
  
  You can read a fair number of reviews of iFi Gear over at Head-Fi and reviews/discussions over at computeraudiophile, just do a search on either side:
  
  http://www.head-fi.org/
  
  http://computeraudiophile.com/f8-general-forum/
  
  Now a quick, what do they do list:
  
  iUSB Power
  
  http://ifi-audio.com/en/iUSB.html
  
  Provides squeaky clean power on the USB Bus, break Earth/Ground loops and thus reduces differential mode noise from earth/ground loops. In many ways the first line of defence, especially for devices (DAC / DCC) operating on USB power.
  
  Prepared ready for the use of "Split Link" USB Cables that separate power and data into separate cables and on separate connectors.
  
  Also the solution if the USB connection adds a lot of buzz and you do not want to use cheater plugs on earthed gear for electrical safety reasons.
  
  iTube
  
  http://ifi-audio.com/en/iTube.html
  
  Tube Buffer, removes loading by cable and load totally from your sources output (use very short low capacitance cables to the iTube to retain the benefit), thus keeping it always in Class A. Outputs are Single ended Class A and can drive 600 Ohm loads without problem.
  
  Add's "Tube Magic" (for want of a better word). Note THD + N is very low (independently measured as 0.004% IMD+Noise), this is not a "2nd Harmonics distortion generator". With optional 6dB gain and volume control to act as single source preamp.
  
  Plus Digital Antidote, an improved version of Tony Taddeo's design from the 1990's.
  
  Plus 3D Sound, this is based on the work of Blumlein and EMI on stereophonic sound recordings and corrects fundamentalproblems with "pan-pot" and "minimal miking" Stereo.
  
  Each of the features addresses specific issues, please see the whitepapers on facebook for details.
  
  iLink
  
  http://ifi-audio.com/en/iLink.html
  
  If you have a great older DAC without USB input or with a very limited quality USB input and you like the way it sounds but want to go computer Audio, this one is for you.
  
  Async USB and outputs include JET Jitter reducer and different output levels and are explicitly and specially designed to get the best (read lowest jitter in the recovered audio output) out of the "common garden" SPDIF input using AKM, Burr Brown, Crystal/Cirrus Logic and Wolfson Micro Receivers in the real world, as opposed to designing for some abstract platonic ideal that actually degrades real-world performance.
  
  Also works great with greatly elaborated SPDIF inputs, such as the Tube SPDIF inputs on the DP-777 (though this does not benefit from using SPDIF over USB, so iLink is not recommended).
  
  iPurifier
  
  http://ifi-audio.com/en/iPurifier.html
  
  Re-balance the USB signal (USB is a balanced transmission line at 480MHz and very sensitive to imbalances).
  
  It also reduces differential mode noise on the ground/USB Power lines and reduces common mode noise on the Data lines.
  
  This one is really more for the final touch to get the last few percent from a USB based Audio device and usually other measures should be taken first.
  
  Mercury USB Cable
  
  http://www.musicdirect.com/p-161062-ifi-mercury-usb-cable.aspx?source=igodigital&
  
  Currently back-ordered, next delivery planned in late March.
  
  The Mercury cable is the "Single Link" version of the more elaborate Gemini Cable. Using the same data cable it has less elaborate grounding and no separate power section. "Full Metal Jacket" USB Plugs.
  
  It is best used with DAC's that do not use USB power at all or for example as PC link upstream from the iUSB Power. Extensive filtering of common mode noise - includes "tunable" noise filters.
  
  Gemini USB Cable
  
  http://ifi-audio.com/en/Gemini.html
  
  Split link cables has completely separate cables for power and power ground and differential USB signal and signal ground. "Full Metal Jacket" USB Plugs.
  
  It is best used with DAC's that use USB power as auxilary or main power source or for example as DAC link downstream from the iUSB Power. Extensive filtering of common mode noise - includes "tunable" noise filters.
  
  Real world Examples
  
  Past that in practice for which gizmo's in which context in order importance. Forgive me for only using iFi/AMR products in this list, it is not to promote them, but rather to avoid any appearance of criticising or putting down competing products by suggesting they need our "fixes".
  
  A) USB DAC, no Tube output, uses USB Bus Power as main power source (e.g. iFi iDAC - runs 100% on bus power)
  
  - 1) iUSB Power - in most cases nothing will help more than clean power
  - 2) iTube - if the cost of the DAC justifies it
  - 3) Gemini USB Cable downstream from iUSB Power
  - 4) Mercury USB Cable upstream from iUSB Power
  - 5) iPurifier - optimise USB side to the max.
  
  Note, the full upgrade set costs nearly three times as much as the example DAC. This is just an example of the different optimisation steps applicable to any DAC using USB power and without Tube output.
  
  It may not be very cost effective to get the "full monty" package, though the resulting performance is quite special. Plus, the "full monty" package remains completely usable if the DAC is later upgraded. I would advise to be cautious and proceed step by step, preferably with home audition.
  
  In my own office system I do not use the expensive cables and the iPurifier, only iUSB Power and iTube (also as preamp) with iDAC and find the results very satisfying.
  
  B) USB DAC, no Tube output, uses USB Bus Power as auxilary power source (e.g. iFi iDSD - internals run on Battery, but charging from USB Bus)
  
  - 1) iTube - nothing like Tube Magic and Digital antidote to cure digititis
  - 2) iPurifier - optimise USB side to the max.
  - 2) iUSB Power - test first for improvements
  - 3) Mercury or Gemini USB Cable - if the cost of the DAC justifies it
  
  In my office system when playing the iDSD nano (which operates from the internal battery even when on USB power) I use iPurifier over iUSB Power (actually bigger upgrade in that context) and iTube (again, also as preamp). I will add a Mercury Cable when the next delivery arrives.
  
  C) USB DAC that does not use USB Bus Power at all and has tube output (e.g. AMR DP-777)
  
  - 1) iPurifier - Clean up RFI, Re-balance Signal
  - 2) Mercury USB Cable - better USB Cable, strictly for signal
  
  The above is exactly what I use in my system, I find no difference between Mercury and Gemini Cable in this system but the iPurifier is a no-brainer given the level of improvement. I am actually using one of the first prototypes, I refused to give it back after it was in my big system... ;-)
  
  D) High End SPDIF DAC and has High Rez capability via SPDIF but not USB (e.g. AMR CD-77.1/777 via SPDIF Input - undocumented and unsupported but can operate up to 192KHz despite being rated as 44.1/48KHz only)
  
  - 1) iLink - provide SPDIF signal from PC
  - 2) iUSB Power - clean power for iLink
  - 2) Optional for Non-Tube (and even many tubed) DAC - iTube - Add "Tube Magic etc.)
  - 3) Gemini USB Cable downstream from iLink - better USB Cable
  - 4) Mercury USB Cable upstream from iLink - better USB Cable
  - 5) iPurifier - optimise USB side to the max.
  
  The above will allow an older, but nevertheless exceptionally musical and great sounding DAC (okay, the specific items are CD-Players in DAC Mode) to give the same high performance while running Computer Audio including High Resolution Audio. With both units and other similar "level" DAC's from other manufacturers I would probably go "full monty" right away, no point messing about.
  
  I hope all of this helps a little and gives background and context.
  
  Ciao T
  
  Sometimes I'd like to be the water
  sometimes shallow, sometimes wild.
  Born high in the mountains,
  even the seas would be mine.
  
  (Translated from the song "Aus der ferne" by City)
  
  

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• RE: How to get the best out of a USB Dac? - jsalve 15:28:33 02/22/14 (0)
  In Reply to: RE: How to get the best out of a USB Dac? posted by racerxnet on February 22, 2014 at 11:52:48

  You've got quite a system there, congrats!
  
  Yeah hoping too the experts here would chime in.
  As I'm getting cross eyed reading/looking at all the options...
  

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• RE: How to get the best out of a USB Dac? - Roseval 13:07:49 02/22/14 (3)
  In Reply to: RE: How to get the best out of a USB Dac? posted by racerxnet on February 22, 2014 at 11:52:48

  2. Upgrade to an ESI Julia Card (isn't this what Bryston BDPs use?)
  
  Won't do in case of a USB DAC :)
  Beside it is a bit dated (drivers)
  The Well Tempered Computer
  
  

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  • RE: How to get the best out of a USB Dac? - jsalve 15:03:19 02/22/14 (2)
    In Reply to: RE: How to get the best out of a USB Dac? posted by Roseval on February 22, 2014 at 13:07:49

    Thanks Roseval...
    I thought Bryston use Juli@ for USB out. Hmmmnn
    Just curious, what do you recommend?
    
    Thanks
    

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    • RE: How to get the best out of a USB Dac? - Roseval 15:20:10 02/22/14 (1)
      In Reply to: RE: How to get the best out of a USB Dac? posted by jsalve on February 22, 2014 at 15:03:19

      The juli@ is a sound card so analog and SPDIF out, no USB of course
      http://www.esi-audio.com/products/julia/
      
      I would simply start with the USB from the PC.
      Try different media players but most of all try drivers like WASAPI for bit perfect output and automatic sample rate switching.
      
      If you go the JRiver way, some setup instructions can be found on my website
      http://thewelltemperedcomputer.com/SW/Players/MC14/MC_Playback.htm
      
      USB interfaces can be found here: http://thewelltemperedcomputer.com/HW/USB_Interface.htm
      
      
      
      The Well Tempered Computer
      
      

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      • RE: How to get the best out of a USB Dac? - jsalve 15:31:27 02/22/14 (0)
        In Reply to: RE: How to get the best out of a USB Dac? posted by Roseval on February 22, 2014 at 15:20:10

        Checking out your site now, thanks Roseval!
        

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