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iDAC 2 - Quad DSD256 / PCM 384Khz / USB DAC & headphone amp

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On 12/31/2017 at 9:07 PM, Les Habitants said:


I own this combo and use it in my bedroom system, you won't regret this purchase, it punches WELL above it's weight class.

thx, good to get some reassurance.  Do you think upgrading USB audio cables between both computer/iUSB and iUSB/iDac, will add any sonic difference?  The cables that come with the iFi units look to be good quality, are USB 3.0, and are very short.  My hope is that these cables will not pose an issue given such short length, especially with the reclocker in the mix.  And the USB 3.0 spec - no idea if that is superior to asynchronous transmission integrity.  My gut feeling tells me I'll be fine with the stock cables, but gremlins always seem to punch me in the gut when it comes to my audio fidelity quest.  


I read somewhere, can't remember where, that appliances like the schiit eitr or the iUSB3.0 have much more "apparent" effect on SQ than USB cables, and cables would only be the "cherry on top" if you will.  

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Been listening to the iDAC2 for a few nights now.  Not ready to share thoughts at this point, other than to say, so far so good.  I am not having buyer's remorse, let's put it that way.  I still have to allow my brain to adjust to it before I can make comparisons or really speak to its strengths/weaknesses.  

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12 hours ago, Em2016 said:


Can you remind me what your chain is, feeding the iDAC2? Only if you don't mind of course.


I found that the better quality the USB bus power (cleaner), the better the iDAC2 performed.


I got my old man (my dad) the iDAC2 and it's being fed by a Sonore ultraRendu & Uptone LPS-1 combination that I got him also, with all music being up-sampled by Roon to DSD256. It sounds incredible.


You don't NEED all that for it to sound great. The above is just to take an already great DAC another level up, sonically (to my ears anyway).





MacMini late 2014 , 8 gigs ram, I5 2.6ghz processor, SSD.  Audirvana plus 3.2.4 with a couple top shelf AU plugins (fab filter proQ2 and Goodhertz can opener studio).  USB cable to power supply/reclocker, then another USB cable to the DAC.


I opted for the nano iUSB3.0 power supply/cleaner and USB regenerator.  I haven't done any real A/B with and without it in place, but I hear the DAC as being devoid of any noise while using it.  I'm not sure how noisy Mac minis are in the first place, but figured it was an appliance that wouldn't hurt to have, being as serious about computer audio as I am.  That said, I certainly didn't pick up on any USB noise using my Schiit modi multibit when plugged straight into the Mac. 

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or jitter for that matter.  Actually, while I can hear the effects of transient smearing based on digital filters used, I can't say I've actually heard "jitter".  Not sure what to listen for.  Ditto USB noise.  Not sure if that's something that's readily apparent if there's a problem, or if all computers have it, and I just can't pick up on it.  


More testing on my end to come - with and without the regenerator on both of my dacs.  

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  • 1 month later...
On 12/11/2017 at 1:39 PM, AMR/iFi audio said:


Minimum/Listen Filter selected: 

  • 44.1kHz .. .48kHz -> No ASRC, synchronous oversampling to 352.8/384kHz using ultra short FIR (minimum ringing Bezier) digital filter 


Specifically for iDAC2 - When you say "minimum/listen" are you referring to minimum ringing or minimum phase?  I think the former is what is meant by these descriptions and also after reading the article on the nano idsd:



Is the "minimum/listen" setting still technically a linear phase filter but with reduced delay of the input signal (less pre and post ringing)?  The impulse response appears to be symmetrical, like a traditional linear phase sharp rolloff filter, but with visibly less ringing before and after the transient (see pic).  At least this is how it is shown in the idsd article.


When I think of minimum phase, I think of the filter in the dragonfly red (see other pic), which shows all the ringing post transient.   I'm still learning and may not understand the difference between minimum ringing and minimum phase so please forgive my ignorance. 


So is the iDAC2 impulse response symmetrical like the iDSD nano or does it dump all ringing after the transient spike like the minimum phase filter in dragonfly red?  Is it right to call this, technically speaking, a minimum phase filter?


ifi filter.jpeg

dragonfly ir.jpeg

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  • 2 months later...
On 12/11/2017 at 1:39 PM, AMR/iFi audio said:

Bitperfect filter selected (all micro products only):

  • 44.1kHz ... 384/768kHz -> No ASRC, no upsampling, no digital filter
  • DSD64 ... DSD256/512 -> No ASRC, no upsampling, no digital filter


so there is an analogue filter i'm assuming.  It seems that the analogue filter imposed by the "bitperfect" setting is static.  Meaning that it starts to rolloff well below 20khz regardless of sample rate being played (except 352.8 and 384khz)  


I've tried this with 2x and 4x PCM 44.1 content and I can hear the rolloff when in bit-perfect position.  Yet when I play 8x PCM (352.8khz) content, it sounds like it is extending the high frequencies further, without this noticeable rolloff.  


Am I hearing this correctly?  Is this what is happening?  The analogue filter is defeated (bypassed) when sending 8x44.1 or 8X44.8?  

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