I don't like the sound of my system. Help please.

When was the last time the CJ was serviced? That piece alone can have endless variables that affect the sound...

Some things you might want to consider, before replacing components:

If you haven't already done so, item one on your list should certainly be verifying that the Vandys are connected in phase with each another, as Mapman suggested.

Next, is the ARC 150.2 located close to (within a few feet of) the other electronic components? If so, I would try moving it as far away as possible from them. Apparently its implementation of Class T amplification results in its being a powerful generator of RFI (radio frequency interference), which could be coupling into the other components and affecting audible frequencies via intermodulation effects, effects on jitter in the CDP, etc. From this review:

I encountered one small glitch while using the 150.2. I use rabbit ears to grab the local CBS affiliate (channel 3) off the airwaves, and the 150.2’s digital circuitry interfered with signal reception on every TV in the house. Turning the amp off solved the problem, but keeping it on all the time improves its sound. In my case, I simply didn’t watch CBS for the review period! Audio Research says that the problem may have been eliminated due to CE testing for European sales, however.

Also, try plugging its power cord into a different duplex outlet than the one powering the other components, and keep its power cord and the speaker cables away from interconnect cables and other power cords.

Regarding the preamps, given that both of them are probably more than 20 years old it certainly seems possible that their condition is a factor, as Elevick suggested. And even if they and their tubes are in top condition, IME changing from one brand of small signal tubes to another (whether the tubes are vintage or currently manufactured) can sometimes mean the difference between disappointingly thin sound, and rich pleasing sound.

Regards,
-- Al

" Apparently its implementation of Class T amplification results in its being a powerful generator of RFI (radio frequency interference)"

Excellent point!

RFI noise from an older switching amp is quite possible. Physically and electronically isolating it as best as possible can only help.

"Sell the speakers to me. That's my suggestion. How old are they? That may not help your sound, but it would help me:)."

Then you would just be going from one mediocre speaker to a slightly better sounding mediocre speaker. Set your sights higher......

Shakey

I would let go of the Vandersteens. I'm not impressed with those. Rolled off highs, and a emphasized lower midrange/upper bass. This is my opinion, of course.