Help I have not bought equipment since mid 80's

I am new to the hi-fi world. My old stereo was purchased in the mid 80's when I was young and poor, therefore Lo-Fi (it survived a divorce, the ex didn’t even want it). I listen to music most of the day, so I want to hear music that makes me feel alive. Recently I decided to purchase a new stereo. Talk about overwhelming, and what a strange trip it has been. Going to the local stereo dealers is like walking onto a used car lot. They raved about B&K, and I ended up purchasing a PT5 and 4420. This thing sounds terrible, or at least it is not what I am looking for. When I told the guys at the local stereo shop this they look at me like I lost my mind. They are difficult to work with, they would like it if I just walked in, made a purchase, went home, shut up, and accept the crap I’ve bought. Anyway, this is what I currently have:

Pre: PT5
Amp: Krell 2250 (owned less than 30 days and can still return it)
Interconnects: audioquest viper
CD: Krell 280cd (owned less than 30 days and can still return it)
Speakers: Energy Veritas 2.4
Speaker cables: audioquest double bi-wire CV-6

I like the Krell sound, but I am willing to check other brands. I am considering a Krell 2250, 280p, and a 280cd. Is it worth the extra money or would a used 250a, 250p, and 250cd be a better choice? Or perhaps a mix of the two? Or would some other line of Krell be a better choice? Another brand perhaps? Any advise for a novice?
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Pre-amps are much more important than many people originally think. If you were to put something better than B & K in I think you would be much happier.

I'm not a real big fan of AudioQuest cable. I used to have all AudioQuest, but I got rid of it.

Those two are the weakest links of your system, IMO. It would sound better with other cables and a better pre-amp.

Krell is expensive, and sounds great.
I am in complete agreement with Rhum Runner. What you need is a competent guide through the crowded electronics marketplace. In the absence of a trusted friend with expertise in audiophilia, a good salesperson can be invaluable. A good salesperson can guide you toward identifying your musical priorities, and then setting up systems for you to audition that won't surpass your financial and domestic limitations. They should be patient while you educate yourself, and even encourage comparisons between their most suitable systems and those from other dealers. The best salespeople realize that helping a customer find happiness with a music system will mean return business and referrals, even if that means that the customer purchases an item or two from another dealer. Finding such dealers and salespeople can require patience, but the reward is substantial. It can even lead to gratifying longterm friendships.
1. Budget?
2. 2 channel or Home Theater(if so, what percent music vs movies)
3. Happy to buy used & demo to save 40-50%?
4. Where do you live...we can recommend dealers
5. Describe your sonic priorities

Lots of good advice here but here is where to start. Bring along your favorite music (a variety to listen to) and pick out a pair of speakers that you like first. Once you hear the pair you like then you can find out from other Agon members with the same speakers what amp to mate the speakers with. You DO NOT have to spend big bucks to get great sound, just system synergy. The Krell amp is very good for the used prices they go for but not for the $4K list price. Once you have the speakers and amp matched up, then focus on a source and then a preamp. There are some who will tell you that the preamp is critical for great sound and they are right but you need to hear what a good source will do first and then see what peramp will provide the best sonics and not reduce the sonics of the source.

Hope this helps.