Benefits of an external DAC


I need a sounding board from you folks.  I have a slightly upgraded Oppo 103 CD player that was a big SQ improvement over my Consonance tube CD player.  I need a DAC to take the stream from my iMac, turn into an analogue signal to my preamp.  Lots of folks rave about the benefits of an external DAC so, in progression, I got a Jolida tube DAC, a Schiit Gungnir, and a Channel Island Audio DAC.  I connect the Oppo to the CIA DAC with a coaxial cable.  I input the analogue signal from the Oppo into my preamp with RCA IC's.    

It is easy to switch between DAC in the path vs. the Oppo analogue signal straight into the preamp.  I tell ya, I have done the comparison between all three DAC's vs. the analogue signal run from the Oppo to the preamp and have been unable to discern any difference.   Zero, zip, nada.  I have done the comparison with lots of audio pals and nobody hears a wits worth of difference.

There clearly are lots of devotees using external DAC, but in my system (with a Don Sachs tube preamp, Pass Labs First Watt F5, and Spatial Audio M4 Turbo S speakers, with good cabling), I am perplexed as to why the use of an external DAC makes no difference in the SQ in my system. It sounds exactly the same.  

I am awaiting a demo of a Denafrips Ares DAC to see if this well-regarded DAC does something to the SQ -- one way or another.  So far, the employment of a DAC to improve the SQ of the signal from my Oppo has been an utter waste of time.  What am I missing?
whitestix
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@shadorne. I don't really know where Stereophile ranked my two DACs, the Mytek Manhatten and Bryston BDA-3.  I imagine that since they reviewed each DAC very favorably that they have them high on the pecking order.
  Regarding cost, the Manhatten was going for 5K new (mine was a demo so I paid less) and the Bryston was $3.5 K.  I've written on this before so I hope that I'm not being redundant but I purchased the Bryston specifically because it has HDMI.  I own a lot of SACD and Blu Ray Audio and wanted to play the DSD and DTS streams in my two channel system.  I thought that I would be selling the Mytek but found I can't live without it!  If only it had HDMI it would have been the perfect DAC.  The Mytek is much more transparent than the Bryston on Redbook or when accepting digital feeds from my Bluesound Vault2, but the Bryston is no slouch with Redbook and has enhanced my SACDs.  The Bryston certainly bests the Oppo with both Redbook and SACD, and I lived very happily with the Oppo as a DAC for 2 years or so.
  So based on comparing the Bryston, the Oppo, and the Manhatten, my experience confirms that as one ascends towards the $5K mark in DACs they just keep getting better.  I wish that I could go all the way until dcs territory but I've hit my limit
Stfroth,
You have a solid take on my dilemma. so thanks for the erudite post.  The Denafrips Ares audition is in the works at the moment and I am keen to audition it.  What totally perplexes me is that in the comparison of my CIA and Gungnir DAC's to the Oppo straight into the preamp, I frankly could perceive no difference in the SQ either way.  Trying as I could, with a pal switching back and forth on the selector switch, there was absolutely no perceptible difference in SQ in any fashion with or without the DAC in the path.  Bring on the Denafrips DAC and let's see what I hear.   :-)  
If you don't hear a difference then be happy.  Chips have sound characteristics but it comes down to implementation such as the power supply, etc. already mentioned above.  My friend recently compared two R2R Dacs, one tube DAC $7500 and one SS DAC $2500.  The higher priced tube dac has a 30 lb power supply with top quality caps and resistors, chokes, copper chassis, etc.  While the SS R2R was nice sounding, it could not reproduce what the tube DAC did in his system.  I don't remember his exact words  but the tube dac had a bigger soundstage, tone was better, details and layering was better, definition was better and it was quieter, etc., etc.  Worth the extra money?  That is up to what you want your system to sound like. For a casual listener maybe not, to a person who really values those attributes, probably. 

He also tried the DACs direct into his amp and using a SS preamp.  Without the preamp the details were amazing BUT with the preamp the soundstage was much larger.  Again preferences.  

So it really comes down to what you are hearing and how the DAC is designed.  If you don't hear a difference than try something else or just be happy.

Happy Listening.

bigkidz,
I do have a Denafrip Ares en route to me for a demo, similar in price to my CIA DAC, so I will give the a listen to it in my system. I can hear clear differences in SQ swapping amps, preamp, tubes, cables and speaker wire, but I will be damned if I hear any difference with modestly-priced DAC such as I have or have had compared to my Oppo.

I will get back to you guys early next week with my impressions of the Denafrips DAC.  If it doesn't improve the SQ of my system, then as you suggest, I am going to "just be happy".  I am enthralled with the sound of my system as it is.   Thanks.