I’m sure this question will raise a bit of controversy, but here we go…
I’m an all digital listener, and I have a streamer connected to an outboard DAC (PS Audio DirectStream DAC), the analog outs of the DAC connected to my preamp, and from the pre to my power amps, and then speakers… obviously.
I’m interested however in doing some room correction/ EQ. If I were to place a MiniDsp SHD in between my preamp and my power amp, the MiniDsp would take the analog signal my DAC created, run it through an ADC, apply EQ in the digital domain, and process the resulting signal through its internal DAC, before passing it on to the power amps. Does this completely negate the value of my PS Audio DAC, or would the initially improved analog signal it created by way of noise reduction, reclocking, DSD up sampling, etc., be of benefit to the final outcome? Would I only be hearing the “last DAC” located in the MiniDsp?
I would suggest using a miniDSP SHD Studio instead, unless you already own the miniDSP SHD. With the MiniDSP SHD Studio you should be able to keep everything digital until your DAC. Streamer to miniDSP to DAC. I think the PS Audio DS DAC is probably better in SQ than the one included in the miniDSP SHD. I think that avoiding an extra conversion through an ADC is better. I was originally using a miniDSP SHD Studio between my streamer and DAC. I eventually upgraded to using Audiolense XO room correction and ended up selling my miniDSP SHD Studio. Hope this helps.
That actually helps a lot. I wasn’t familiar with Audiolense XO either, so you helped twice!
Using Audiolense XO is a much more expensive route. I just wanted to make sure you understood that up front. With the miniDSP products you get a USB microphone to do the room analysis. With Audiolense XO you will need to buy a microphone (suggest not using a USB microphone, usually run around $400) and a microphone preamplifier. Also you need to figure out how to get your streamer signal into the PC running the Convolver (used to process the digital signal using the Audiolense XO room correction filter). If you decide to consider this route you can PM me for more specifics.
Definitely use whichever miniDSP/myDSP device does digital in and out and put it between digital sources and DAC. I have tried it both ways with a different “mid-priced” device, the behringer DEQ2496.
Using the analogue ins/outs was not as good sounding as using the digital ins and outs fed to a different (better!) DAC.
Even if you couldn’t hear the difference (and you probably will) it is still an antidote to audio-paranoia to do it the best way, otherwise in a year you will still be wondering if using the extra ADC/DAC is affecting the sound negatively or not 
p.s. for room correction type of stuff, the Behringer I mentioned is probably getting a little long in the tooth, it only has the simplest of room correction which doesn’t adequately handle bass (or at all, if you don’t force it to).
It’s been around for 20 years or more, but still made and sold because it is so useful for other things, AND it has a very nice spectrum analyser as one of its functions for those of us who like visual feedback 
I liked it so much I bought two (they are only 2 or 3 hundred UK pounds)
If you use Roon you can do it very easily with a convention filter. REW and a cheap mic fro miniDSP.
I have a bit of a different perspective (experience) than some of those posting above.
I send the analogue output of my DS Sr. (MK I) to the analogue inputs of my Anthem AVM50 v2 preamplifier/processor. The Anthem has room/speaker correction software, Anthem Room Correction, which I (and many users and reviewers) believe is an excellent product that can yield excellent improved results in a stereo and home theater set up.
I have noted among these threads previously that I have benefitted from (perceived) most, if not all, of the firmware updates @tedsmith and PSA issued for the MK I, despite the fact that I converted the analogue output of the MK I to digital via ARC and back to analogue via ARC before sending the signal along to my mono amplifiers.
So, as is often suggested, try “it” both ways and see what sounds best to your ears in your system.
FWIW.
No not at all. You are taking an Analog output and sending to an ADC for processing. I did this with my 1968 Bose 901’s and applying a slightly customized curve via the balanced input/output MiniDSP non HD version (no longer available). It worked astonishingly well. Seems silly to take a $5k DAC and shove into a $50/ch ADC. Basically no different that using exotic cables or changing the output Transformers inside the PSA DAC…I’m exaggerating a bit…but not really).
I once asked Ted if build me a special firmware update with my Bose curve…uhh…no can do Joe…LOL.
New Record Day Ron did build a custom curve for my 901’a via Roon but no good for me since I’m not a Roon user.