Could I make use of a DAC with my setup?


I stream music (Spotify Premium) from my PC via 3.5mm cable into a Parasound P5 preamp, which is hooked to a Parasound A23 amp, and from there to Klipsch Fortes that I purchased new in 1986, I think. 

I had the impression that if I use a DAC before the P5 preamp, the DAC's output would be "reprocessed" by the DAC in the preamp, and, therefore, useless.

Is my impression correct?  Thanks!
forsooth
That's why I was curious as to why you  didn't use the usb on the P5. Since you have plans to upgrade the computer you could continue what you do and when you get a new computer try it with usb if it doesn't perform like you want then try a seperate dac. The dac in the P5 is a pretty good one.
I too am waiting to try Qobuz I hope my integrated amp will support it like it does Tidal. For info purposes my amp is a Micromega M100 which is a streamer as well makes things a bit easier. I am all for ease of use. 
OP... I'm not sure what PC you are using, but the 3.5mm output on a Mac is digital when fed to a digital device.

@djones51 I looked up the Micromega M100, and that looks like a pretty awesome piece of equipment.  They are not giving them away, either.  :'>  The company makes an array of audio products - cd players, DACs, etc. - pretty impressive.  Have you tried their MyDAC?
@lowrider57  I'm using an old Acer desktop that originally came with Windows 7 (I think) and now has been "upgraded" to Windows 10.  Every time I get an MS software update, the USB keyboard and mouse stop working and I have to unplug and plug each to get them work again.  Definitely long in the teeth, but, overall, it is like my 2001 Toyota Echo -- it just keeps going and going.