another rookie question - preamp or or power amp

thanks @ellajeanelle I was hoping to get one component for about $400, to upgrade and then later on upgrade the other component

thanks OP ...

I prefer the look of my other Sansui AU 7700... But i use it no more for now ...

The alpha 607i is a notch over it though in all aspects save flexibility...

It was so amazing that he drives better my headphone K340 than one of the best tube headphone amplifier on the market ...It takes me minute to compare because he beat it on the spot... I never imagined that an headphone out of a 100 watts speakers amplifier will beat a top tube headphone  amplifier with not even a comparison because i lost near 300 bucks in this trial comparison ( save the ratio noise /signals was better on the tube amp because his separate linear power supply was a top notch one). but all others characteristics were better with the Sansui , for example the out of the head impression, the timbre, the deep bass the imaging and soundstage ... The alpha was the top of the Sansui history ... mine is only the first basic model ... Imagine the rare top one existing only in Japan at high price even after 25 years or more ... In my headphone it is evident that the sound is tube like even if it is an S.S. amp... The best realistic timbre i listen too speakers included ...

@mahgister the Sansui looks awesome!

I had always thought that conventional wisdom dictates that "getting it right up front first" yielded the most notable sonic improvements.  And by that logic, the preamp section would be the place to start.

Is there any possibility to try before you buy?  Or to possibly buy from some place like Music Direct and return if things don't work out like you want them to?

grislybutter OP: If looking for an amp only, take a look at a Vintage Denon POA 2200, if you can find one or an Adcom GFA 555.  They are around your price range used and in a different (higher) league than that Parasound. No offense to you or anyone, but Parasound is geared more toward home theater than hi fi. 

. . . to relate my own limited experience, I got into separates in '94 and it was an immediate entrance down the vacuum tube rabbit hole.  Except for the preamp.  Anyway, since then, I have only owned three different tube amps (I still own two of them) and 3 different preamps (and I still own all three of them), so I am not trying to come off as the know-all/be-all last word of wisdom.

My first upgrade (it was an amp ugrade) was a major equipment upgrade.  Definite expansion of width and depth and height of soundstage . . . but still sort of missing something that I thought/knew must be out there.  At that time I was using a B&K digital HT (Dolby Prologic) pre. It didn't sound bad, it didn't sound good, it just sounded. I came across a real affordable deal on a VAC two channel preamp with a pair of 12AX7s from Audio Advisor so I ordered it and I truly WANTED it to sound good.  It didn't.  Nails-on-a-chalkboard.  I sent it back.  In '99 I came across one of the few local dealers (he no longer exists as such) who had a used and wierdly modded Cary SLP90 for sale so I auditioned it for a weekend.  It had one of the six tubes basically out, and the cabling the dealer sent me home with (an adapter to go from RCA out to balanced in on the pre) was totally wrong, but despite all that, and the fact that all of the above made it sound like hammered crap, it truly sounded musical.  Based on the changes I felt I was going to have make, I made the dealer an offer that he accepted.  I replaced the tubes and got the right cable (balanced out to balanced in) installed, and it was really the great sound I had wanted.  (I later sent it to Cary to undo some of the previous mods.)

Down the road I changed amps again, not because of sonic quality but because of reliability issues, and about three years ago I saw what I thought was a decent price on a preowned preamp that I had always sort of been lusting for (plus the fact that I thought my SLP 90 was sounding tired), and the most recent new to me preamp I put in my system did impart sonic differences--not as sweet and warm as the preamp it replaced in my system, but more detailed and more "spacious" (if I dare use that word).  A larger sonic presentation.

Anyway, TMI I am sure, but this is what I have personally experienced with different preamps and amps in my system.