[Lucky1]

Hi everyone, first post here so I'll try to keep it short and sweet
On my desk I currently use my HIFIMAN HE400S headphones and my Polk TSX 220B bookshelf speakers, but with a very old, pre-digital receiver with not so great headphone capability at all, everything sounds whisper thin and anemic, and I feel that the speakers could be better as well, and might get something a bit more high end. What would you guys recommend? Should I
1. Put up with it
2. Replace the receiver with something more modern (Will this make a big difference in sound quality?)(Around $400 USD)
3. Replace the receiver and upgrade the speakers (Want to spend around $700 USD)
* I only really use them with my computer
4. Ditch the headphones and go for a speaker that includes the amp in it
I recently listened to the KEF LS50 wireless and those were phenomenal

 

[ProtegeManiac]

2. Replace the receiver with something more modern (Will this make a big difference in sound quality?)(Around $400 USD

If you had no problem with the receiver for driving your speakers right now this is the riskiest for the lowest possible gains to your set up. Whatever speaker integrated amp or network receiver you get might not necessarily have more clean power than you need for your speakers over your receiver (ie you're limited by how loud you can go before the neighbours complain), and even if it has more power or higher gain for your headphones, nearly all of them out there have a high output impedance on the headphone output. They'll go louder but you either get bloated bass or a tin can with bass that still lacks refinement.

3. Replace the receiver and upgrade the speakers (Want to spend around $700 USD)
* I only really use them with my computer

You'll improve the speaker chain but you still have that problem with the headphone output as discussed above.

4. Ditch the headphones and go for a speaker that includes the amp in it

Why ditch the headphoones when you can get a DAC-HPamp-Preamp or DAC and HPamp-Preamp that will take the digital signal out of your computer then either send out its preamp signal to the speakers or into its own amplifier stage to drive the HE400i properly.

You can get something like the AudioGD NFB-11 or R2R-11 with the KEF powered speakers (you won't use the wireless this way though but at least you can use the smartphone as a source and even move it out of the room and into the patio during a BBQ).

 

[Monsterzero]

Normally vintage receivers make for awesome HP amps.In fact I own six of them.
Whats the make and model of your receiver?