Background noise?

Hello, all. I'm new to high fidelity music listening and recently put together a decent sounding system (for a beginner anyways). And for the moment all my music is being streamed via the Bluesound Node 2. I've only been listening to my new investment since this past Friday and have already noticed that I'm hearing new sounds in songs that I've listened to hundreds of times before. 

One song in particular stands out though: The Doors' L.A. Woman. Because it sounds like there is a tape reel recording in the background. It's most noticeable from my left speaker (if that matters). This is the only song that I've heard this on yet. Anyone have any idea what it is? Thanks.

From what it sounds like, you are hearing what's inherited in the recording.  Your new gear is revealing to the point that it's letting you hear everything, good or bad.  And that's what a properly setup  system should sound.  

If you continue to hear 'tape reel sound' from your left speaker on other recordings then there is a problem with left channel.  

You you may wanna read this article and try to isolate the problem.

Hope this helps!
Thanks for the input and the link, Lalitk. And I believe you are right in that the sound was inherited as part of the recording. Happy listening!  
Glad to be of help.  Enjoy!
By the way, The Doors album I listened to is part of The Complete Studio Set streamed via Tidal. So if you use Tidal you might be able to hear it. It's most noticeable around the 3 minute mark after the tempo changes.