The law of diminshing returns?

But in my opinion toggling between DACs on the fly even with all cabling matching is at a minimum less than ideal way to compare DACs. This will only work if you are comparing a $200 DAC to a $5,000 one.

My conclusion is that our aural memory is short and the longer the time between our comparisons, the greater the opportunity for our predisposition toward a certain outcome to override what we actually heard, IMO.

I've purchased 10 DACs over different companies and in very wide price ranges (e.g. Wadia, Berkeley Audio, Bryston, SimAudio, Bricasti, RME, Topping, Mojo Audio, Meitner, Schiit, Weiss)  over maybe the last 5+ years and always compare them with my current one before deciding to keep or just re-sell.   For me, I've found some truth in both statements. 

For even song-to-song comparisons I find I need to take per song notes as often each DAC highlights different things and I find it easy for me to get lost in the differences if I don't have something to refer to, like maybe 'strong bass' or 'recessed high frequencies', etc..    If after going through my standard 'Demo' playlist I'm on the fence then I use a longer time to adapt to each and ultimately make a decision over more prolonged listening (in days) for each.

I personally didn't find I needed to compare similarly priced DACs to hear differences in my system (fairly resolving with Magico S or Spendor D series tweeters...) though.   e.g. RME ADI-2 FS vs (original AK4499) Topping D90 at the time were the measurement based darlings and the RME was something I could listen to long term with no fatigue but hear lots of detail where with the Topping I had to shorten my listening sessions and/or turn down the volume as I found it fatiguing, and returned it pretty much immediately.

The Yggy LIM to me with longer term listening sessions sounded very similar to the Meitner MA3, both very fatigue free and natural/relaxed sounding.  I was initially thinking why spend the extra $$ to keep the MA3.   But in song-to-song comparisons I could determine the LIM seemed to be many rows back in terms of hearing details in my demo recordings compared to the MA3, and decided the extra $$ was worth it to me for those extra details I liked hearing...

Now I have a Weiss that in both long term and song-to-song listening met enough check-marks for me vs the MA3 that I kept it and sold the Meitner. 

Personally, with the well engineered DACs of today from many good companies at very reasonable prices,  I wouldn't assume spending a lot more is going to give you a lot more enjoyment or sonic differences depending on your system and you hearing. With so many good sounding DACs I personally now prefer to spend my $$ on amplifier or speaker differences.    That of course doesn't cover DAC prices related to internal streamers, high quality volume control, etc...    Both the Berkeley, Bricasti, and Meitner sounded excellent to me driving my amplifier direct for instance which in theory could have allowed me to sell my preamp (but I slightly preferred it more in all cases :))...

@ddafoe I had Bricasti M3 when I tried Meitner MA3. I loved the more telaxed, easier flowing but more airy a detailed MA3. Unfortunately my plans for MA3 didn’t work out and I had to return it. I simply couldn’t appreciate the Bricasti any longer despite it being a really good DAC…it didn’t match the Meitner in my system. 
So after several calls to EMM labs, reading reviews and talking to dealers, I blind bought the new Meitner MA3i. EMM labs managed to retain the best qualities of MA3 while addressing a few critical aspects such as dynamics, bass texture and drive and more body in the mids. The new MA3i also seems to be slightly more resolving top to bottom.
These changes are both subtle and significant and were obvious and audible despite the break I had between these two DACs.

There are many factors in comparing components. I never had much luck flipping back and forth between DACs of similar high quality. 
And…probably the most critical aspect of it all is synergy. The overall voicing of your system when the new component lands and how it either disrupts it or enhances it.

@audphile1, I really liked my MA3,  but I guess I would say its dynamics and resolution were not as good as some of the other (even much cheaper) DACs that I've tried.  Like you I really appreciated its relaxed and smooth sound.   The improvements you mention for the MA3i makes it sound like a killer combo and one I would likely love in my system.    The MA3 and Mojo Audio were overall my two favorite DACs.    With 3 kids about to head to college, maybe I can pick up a used MA3i in like 4 to 6 years :)     Enjoy it!

Toggling between DACs is my way of testing DACs. I did this with the Benchmark LA4 preamp, and I used ROON to send a GROUPED stream to both of my fibre optic Sonore OpticalRendu’s. Each Rendu is then connected by USB into a DAC. The DACs go into the LA4 preamp via XLR. I actually had 3 OpticalRendu’s at one time but only tested 2 DACs at time since the LA4 preamp only has 2 XLR’s (and 2 RCA’s).

You can easily switch between the 2 XLR sources and hear in perfect synchronization with the music on each DAC. Now the GROUPED stream maybe slightly less audiophile than single stream. Don’t quote me on that, I needed to test that some more. However, in context of comparing it did not matter since both DACs were getting the identical stream.

My tests with a lot of DACs led me to believe most DACs $15k and under were not that substantify different, more evolutionary improvements. The best DAC was the Schiit Yggi+ OG (at under $3k).

Now I sold all my DACs and preamps and have bought what I think is a revolutionary DAC. It is the Imersiv D-1 and I hear a massive difference in sound from all the other DACs I have heard. The design of this DAC is different for all other DACs and the measurements on this DAC are significantly better than the former best measured DACs. Normally to my ears measurements do not equate great sound but in this case, you cannot ignore the substantial difference between the D-1 and the second-best measuring DAC.

When I got the D-1 I first tried it via the Benchmark HPA4 preamp (same as the LA4). To my surprise I found the HPA4 was limiting the potential of the D-1. That never happened before with DACs always better with the LA4 or HPA4 preamps.

There is no "point" of diminushing returns...

It is a surface whose complex area value is determined by the subjective biases of everyone and the objective qualities of design synergetical impact...

This surface cannot be reduced to a "point" ...

I am lucky with my Dac paid 20 bucks on Ebay bid which i could not upgrade with more modern low cost design for which i tried...SPS Nos battery dac TDA 1543...My system total low cost  is satisfying with no frustration but i cannot buy a costlier dac, it would be illogical and unnecessary anyway ...

Lacking money could be luck and an occasion  instead of fate....