The amps do improve the headphone but not exponentially. The bass tightens, the highs smooth out, and the soundstage expands. But it's not like it's noticeable right away. Heck all my Grado's were ran off my Zune and the difference between amping and not amping were so small. The improvements aren't as big as some members would leave you to believe. Here on Head-FI.org, there are many subjective opinions on amps, headphones, and gear in general, but I'm sure you know this already.
When I had the RS1 I found they didn't improve much with amping. It was hard to discern the differences. Now the Magnums I had were different and benefited from an amp for sure. With the Magnums the bass became a lot more controlled and defined. Without an amp the bass was an loose animal with a mind of it's own.
Now with the "i" versions I have to say there is no difference in SQ. I had the SR-325i and SR-325is st the same time and there was absolutely no difference in sound at all. Same thing with the SR-225 and SR-225i. Many said the newer "i" revision sound brighter and had more bass but in reality there is no change. I would say do not worry about changes at all between revisions because if there is any difference in it's very small.
EDIT: I have an SR-80i and SR-3225is on hand right now and just tried them both amped and direct from my Zune HD and I gotta say there wasn't much of a difference.
Quote:
Originally Posted by
JPizzzle 
Well i'm happy to see your opinion zombie since i don't plan to amp. I do however think that a lot of the improvement that people experience may be due to the type of amp used. From my recent research, I've read that the grados drive well without an amp, but that an amp does provide some improvement. I don't think that it's at the performance gain that some of the other headphones may have from amping. Again, this is not based on my experience, just my interpretation of the different opinions out there.
Also, I believe that I have settled on the Alessandros. My only concern is that the "i" version came out about 7 years ago. How often are these grados updated, should I be concerned that they will soon be redone or something coming out that's a better deal for that price range from grado. Any opinions are again appreciated.
I may have considered the ps500's if I did not have to throw some money into my photography hobby this november and december :).
JP
Edited by Zombie_X - 10/16/11 at 3:22pm