Is it worth it to add a music server just for FLAC files?

Hopefully someone can help with my question.

My current system is a Krell Digital Vanguard Integrated Amplifier and Wilson Cub Series 2 speakers. The Krell has a USB input that I have connected to an external hard drive that contains all of my FLAC files. I control what is playing with the mconnect app on my phone and can stream from Qobuz/Tidal/Spotify if I need to. It all works fine and sounds great to my ears.

My question is other than some GUI navigation improvements what would be gained if I ran my FLAC files through a music/network server (Aurender, etc) before inputting to the Krell? My intention at the moment is to continue using the DAC in the Krell. Not interested in Roon.

What would a music/network server add in my situation?

I know the real experiment would be to get a music server and let my ears tell me, but just trying to think this through right now.

Difficult to say.  I have a NAS connected to my router, which is picked up by my Lumin U1 Mini via MinimServer. All the files: Flac, AIFF, etc play well through the Lumin; however, I do not have a preamp, so cannot bypass the U1 to hear if there are any differences.  My gut says the music server would have a better (less noise) storage device than your hard drive, but that's only a guess.  Maybe someone else has first hand experience.
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@mastering92 What would the tiny desktop add to my setup? SSD -> Krell Digital Integrated which includes a DAC.

BTW - I meant to say I am using an SSD not a HDD. Also I am not contemplating building a server, I would be buying something like an Aurender. :)

I will leave the FLAC/WAV discussion to the many different threads - I am aware of the pros and cons. But long story short for me is that I like the metadata that goes along with FLAC which WAV is not capable of.

Also should mention that it is my understanding music servers like the Aurender’s use regular off-the-shelf SSD drives like what I have in my current external drive.
A Rasberry PI 4 with a free program like Volumio would provide a nice looking  interface and  usb out for not much money.

There are also hats that can change I2S output to a multitude of digital outputs. 
I own a Bluesound Vault2, it’s basically what you have in one package with a DAC and a really nice user interface, in my option much better the Mconnect. My personal opinion is, I love my Bluesound vault, and I use an outboard DAc with it now, but you may not get a big boost in sound quality going to the Bluesound from what you have, but you would going to an Aurrender like an A10 with DAC or better, a N10 that can be run into any outboard DAC. 
Relax your doubts. I don’t think you’ll gain anything in SQ. mconnect is better than BluOS although I prefer piCorePlayer. People that love BluSound don’t know any better since it is dedicated and they are stuck with it.
“What would a music/network server add in my situation?”

A streamer with an internal storage like Aurender N100 going to offer better sound fidelity and excellent user experience (interface) in accessing your rips and Qobuz / Tidal streaming via its proprietary Conductor app. You can pick up a used N100 and let your ears decide :-)
I don’t think that there will be a gain in SQ by adding a server.  If you add a second system, then the server will be able to “serve” the files to that system as well, but if it’s one system only then you aren’t going anything
I have found servers make an enormous difference.  Usually a little less for local files but much more for streaming.  Getting control over things coming in from a very volatile internet is big and the processing power their matters.  Though I did notice that local files sounded smoother with a bit more air.  

^^^DSP is a compensatory tool for less than optimal audio systems and for rooms without proper acoustic treatments :-)

Any use of electronic manipulation or artificial correction of the original signal at first may sound easier on your ears but ultimately it renders music unnaturally. DSP is best for headphones, smartphones or car stereo, there is simply no place for DSP in a well appointed home audio systems.
One of the most profound changes in the digital end of my system was to finally put in a high end music server. The first step was a Auralic.. then I moved to Aurender. The difference was profound. Now the sound quality of CD player played, LAN stored, internally (on streamer), and Qubuz have the same sound quality… well the Qobuz is frequently better as they are higher resolution files.

For years I upgraded DACs and amps, speakers, headphones… passing over the source. My first dedicated music streamer changed all that. Now I recognized the source, like the turntable in analog reproduction is the first critical step in getting great sound quality. My streamer is now the most expensive component in my system (well, equal to my tube amp). Worth every penny. I never play those albums on storage. I listen to Qobuz and have access to more music to explore than I could listen to in a lifetime.

After owning a couple good steamers, audioning a bunch, and several Aurender, I favor Aurender. They really get how to do streaming. The critical importance of the power supply. The audio circuit in mine runs on battery.
I believe the OP was asking specifically about his files stored on a HD.  The query wasn’t about streaming services.  So then the question becomes do files stored on a HD sound better if played back on a bog standard personal computer vs.a dedicated server/streamer.  This goes back to the issue of whether dedicated server/streamers sound better than computers.  In general, they do, but PCs can be optimized for audio playback using a relatively inexpensive program such as Audirvana Plus.  
We have sold aurender and they did sound better then direct streaming

However the innous and 432evo servers offer far better sound then aurender

Roon gives you the ability to upconvert 16 44 to high res or even dsd

We are a krell dealer and the addition of a good server dramatically improves the dac

We can even send you a server to audition

To date anyone who has demoed our 432Evo servers have bought one

They sound that good

Davea And troy

The real question seems to be whether a new streamer platform can offer improved sound. Others have said it here, but just agreeing that 'yes' you can improve your sound by upgrading your streamer. I have been experimenting with standalone streamers this year and keeping everything else the same (i.e. DAC, etc.) there are noticeable differences between streamers.
@ mahler You are correct. I am mainly interested in local FLAC files from a hard drive. Since Qobuz is only about 5% of my listening that is not part of my equation.

The 'less is more' side of me is telling me to stick with just the hard drive -->> keep it simple, less moving parts, cables, etc.

The other side of me is thinking that maybe an Aurender model might smooth things out like is mentioned above.

Am I correct that the hard/solid state drive in a commercial streamer is an off the shelf drive? Meaning like one you could buy off of Amazon or is the storage a specialized/audio centric storage device. 

I really do appreciate everyone's feedback. Thank you.

I'm in agreement with those stating that different servers can dramatically improve your sound quality. Great power supplies and low power dedicated devices have an inherent advantage over devices doing multiple tasks, including most PCs and Macs. Standard computing drives(e.g. Western Digital) can work and sound fine in a NAS or other server. Aurenders, Innous, etc. will sound better than most other one piece servers if cost isn't much of a factor. For those of us on tighter budgets, a NAS in another room with standard drives and an optically isolated streamer like Sonore Rendu is sonically at or near the top class at a lower cost.

Software user experiences also vary widely, so I'd try to get a good idea if whatever is offered will satisfy you from an interface standpoint or you will not be happy in the long run. IMHO, the Roon experience can't be beat, but if you aren't interested, Aurelic, DCS and a few others satisfy many. Lumin is known for good hardware, but IME, there app, relying on standard DLNA/UPnP protocols can be a PITA maintaining network connectivity. It's free and works w/any DLNA/UPnp device, as do other apps from Linn and others. Cheers,
I completely understand where you are coming from. I was there, thinking I just want to use what I have. But at some point I broke through that mind set and realized there was a whole new world out there… It completely blew me away. I look back now and just can’t believe how wonderful this new world is.

I daily listen to music two to three hours a day with incredible musicality and virtually none of it did I listen to a year ago, or last month. I discover new groups an genera constantly exploring whole worlds of music I had no idea existed and with astonishing sound quantity that constantly inspires me.