[kmhaynes]

Back to OP's original question, Yes the S4 will be a pretty good improvement over the EP630.  Everything will be stronger on the S4, and you will do best letting them play connected to a repeating CD for about 2 whole days (40-50 hrs.) to let the drivers settle down a bit.  The S4 can seem harsh straight out of the box -- you can certainly listen to them for a bit to see how you like them, but let them burn in before you make your critical judgement on it.  Even then, you might still want to EQ down the bass just a tad, unless you like slightly overwhelming bass response.
 
Also, the Clip + S4 combo will be fine, and you won't need an amp to drive the S4's sufficiently.  Having said that, when you can afford even the little Fiio E5 for $25, it is a good improvement -- it will sharpen the sound going to the S4.

 

[kmhaynes]

Going back to your OP, yes, the S4 will be an improvement over the EP630.  Everything will be stronger on the S4, but cleaner and clearer.  You will do good to burn in the S4 for about 2 whole days, 40-50 hours (play them on a continuous loop on a CD player or something.)  This will let the drivers settle down a bit, and reduce some of the initial harshness and boominess.  Even after a good burn-in period, you still might want to EQ down the bass a notch or 2 -- it is pretty strong on the S4.
 
The Clip + S4 combo will be a good combo that won't need an amp to drive the S4's just fine.  Having said that, even a little $25 Fiio E5 will sharpen and clear the S4 sound even a bit more, when you can afford to pick one up off Amazon.com.
 
Either hold on to or forget about your wallet!

 

[kristianfredrik]

Oh. No. I never thought of actually buying an amp and I've already ordered the S4.
And to your little note: I think I will hold on to my wallet. 
 
BTW: Can the burn-in process be done in bulks? Burn in with a computer during the day, then turn it off when i want to sleep. ( the fans are loud )

 

[CoryGillmore]

Yeah somewhat. Any hard to drive over the ear headphone will need one when using pretty much any portable source. Certain IEMs can also benefit from an amp.

 

[David58117]

An amp for the S4 would be overkill, don't waste your money on it at this point. 
 
Burn in is just the driver getting used and air pushing through it - some people play certain files (white noise, pink noise, specific music), but just listening to it also works.  What you're talking about will work, but unless you're listening for specific changes (ie, the bass is said to tighten up after 100 hours), whats the point? 
 
Just listen and have fun. 

 

[kristianfredrik]

And I will. Don't have the patience to do a burnin annyway

 

[ketan7s]

Ohh comeone, in other posts, unrelated, people talk about the ep630 and S4 often. And now when the real question arrives dedicated to the same, people keep mum?
I have this and I have that where is it now?
 
KristianFredrik,
Tell soon, what you felt about the difference between the both.
see you.

 

[a_recording]

It can be fun to go through the burn in process listening to it anyway, since you get to keep track of the small changes in the sound over time. I think it helps you fall in love with your earphones! : D
 
*EDIT* And welcome to Head Fi! Sorry, your wallet has little chance.

 

[kristianfredrik]

I got them today
My first thoughts is that i had a little problem getting them to fit and make a proper seal, but the double-flanged ones worked allright. I will work more with the fit.
Sound: At first, i thought the sounded pretty much the same as my old ep630's, but with more punch in the bass. Then, I compared them directly, and I instantly HATED the old ones
S4 has more bass, and it is more accurate with more punch. The overall sound much more balanced and the middle (guitars) is just more fun. More crisp. 
Conclusion: Don't hesitate, just buy them

 

[kristianfredrik]

Add: A little personal experience. After using them for an hour or so, i find it hard to make them fit properly  
So far i can either use the double flages, which gives me bass, etc, but i don't feel that it blocks out all the sound. The other alternative is to use the double-flanges or the medium tips (oval) with the wire over the ear. What i would prefer is, of course, a tight seal with the wire straight down that don't require anny fiddle-faddle to make fit. 

 

[CoryGillmore]

Order some Comply Foam Tips for your fit problem. Problem solved.

 

[kristianfredrik]

Lol, the foams cost half of what i gave for the S4. Think I will pass for the time being.

 

[whistler]

You mentioned earlier the AKG K 450's try - http://www.soundearphones.com/deal-of-the-day at the bottom of the page. Also using site15 adds a additional 15% discount.

 

[kristianfredrik]

Lol, 99 USD is a lot more than where i live, in Norway. xp

 

[martinmach]

kristianfredrik, Did you get them online in norway?