Best Stereo Upgrade Value

obviously lots of caveats all noted above. But assuming you dont have some piece of junk along the signal path, and understand that big changes demand (proportionally) big spend, its almost always either:

1. Speakers

or

2. Setup

you can sometiems get a dramatic *change* from, say a powerful but cold solid state amp to a warm and flabby tube amp, but now you are in the realm of "i prefer this distortion to that distortion".

And i dont mean this badly, i KNOW what distortions i prefer.  Consonant ones.

 G

Clean records. Anything is better than nothing in regards to equipment 

IME, which is considerable, it’s the speaker/room synergy and its relationship to your listening goals and expectations. The rest are details. If you want the singer/songwriter and their acoustic guitar or piano to pay you a visit vs. wanting to relive your one concert hearing AC/DC or Led Zep live makes a huge difference.

Believe it or not, ny best "Bang for the buck" improvement was a $150 USB cable. Almost everything I listen to goes thru that cable. The difference is huge. Try one from Wireworld, Furuteck, or Zavfino.

Anyway, you choose the best source and speakers you can and then fill in everything in the middle. Tuning the room is additional direction. But not all of us can convert the room into a concert hall. Unfortunately.