Which is the most important part of a stereo system?


My system consists of a pair of B&W 630's, an old Denon 50 watt reciever (DRA-550) from the mid 80's, a Marantz CD5004 cd player, and now a Pro-ject Debut Carbon DC Turntable.  I'm pleased with the speakers and the cd player and while the Denon sounds good it has some issues and I want to upgrade.

I'm planning on returning the Pro-ject TT and getting a higher end TT.  I'm also looking into getting a new amp pre amp with a internal DAC.

Is the source the most important? The speakers? 

Please Help!
klimt
"We now return you to our regularly scheduled misinformation." Miller, that was good for a chuckle....keep em’ coming. Not enough lighthearted posting here. Everyone will have their own opinion on this topic. Personally, I subscribe to the speakers as numero uno and have always built my systems from them on out.
Larry
Hegel H190 should also work. I have only heard the H590 but that was good.

I did hear Arcam SA30 which is also an amp  with streaming (roon endpoint).
Did any one mension, your ears  I'm no spring chicken and before I would spend crazy money on cables and power cords etc, I'd get my ears checked. As you might not hear that much difference. I did have mine checked, not bad for my age, but not like they use to be!! 
It’s called a credit card....get one with zero percent for 21 months....then you can get a 2500 to 6000 dollar amp...credit cards are good tools if used wisely and lots of them give generous points back on purchases well a as a nice sign up bonus. For instance spend 1000 get 250 back or spend 500 get 150 back.....Like getting a nice discount on what you want. At 21 months @ zero % I’d say that’s a pretty nice deal. If not paid in 21 months, just transfer remaining balance to another good card offer and so on and so on....I always read posts whereas the person says I’ll never be able to get this or that etc...well you can if you use credit responsibly. Another good example is Music Direct. Every holiday they run a 0 % financing for up to 3 years!... probably the best deal in town. But, I guess I can see how some are afraid of debt...you only go this way once, life is short etc etc 😁
Audioguy is correct. Get 4 to 5 high limit credit cards with cash back or some kind of rewards. Max them all out on some high end audio gear. The amp is 10 grand but you make 60 grand a year? No problem use the card. Speakers 10 grand? Not an issue. Max another card out. Its the most important part of my system.