Newbie with "bright" system

I recently bought a new power amp, and for the first time, my system now hints at recreating a music "venue" rather than playing songs. For this long-time music fanatic, this is incredibly exciting (I now realize I'm hopelessly hooked). Pushing onward, my current system seems "bright" and "harsh," causing listening fatigue at moderate to high listening levels. It also lacks believable bass detail and extension. Looking for low to moderately priced ($300-1500) incremental, high-value upgrades - I suspect cabling and receiver as pre-amp - what to upgrade first?
Arcam Alpha 8SE - CD player
Nakamichi AV-10 as pre/pro
Bryston 4BST
Bettercables IC's and biwire speaker cables
"Industrial" metal rack
Any insight/advice welcome. Thanks in advance for input. Mark
Like you, I had a bright system, and not being able to tweak the room (WAF is an issue) I had to try various gear and wires. Mark, you need tubes in your preamp in a big way and fortunately there's quite a selection to pick from. Some of the better Audio Research or Conrad Jonhson would fit the bill (I've owned several models of both), but if you can stretch just a bit more, I can't recommend Balanced Audio Technology enough. My BATVK30 preamp ($2100 used here on Audiogon) changed my system more than any other component I've ever had in the chain. My system is tamed now, thanks to the adding the BAT preamp, and then buying a "used" BATVK500 amplifier (with BATPAK). One other major change was going from a long run of single-ended interconnects, to Goertz Micropurl with balanced connectors. Musical? Oh YEAH!!!!!!
I agree with Jeff on the preamp. That would be an excellent place to start. I have no experience with the BAT gear, but you can pick up a used Conrad Johnson PV10AL for around $600 that would transform your system. It sounds like butter. I would hold off on the cables until you get a little further along with your system. Now this is something I do care about.
Simple dump the nakamichi and buy a neutral cable and you should be set. Nakamichi is brite sounding gear... Good luck and dont get stressed.
If you are worried about loosing the features that the "NAK" has by going with a tubed pre amp, try a Sonic Frontiers Pre amp. It's tubed but it's a neutral sounding unit with a touch of warmth that if sort of gives you the best of both worlds. It has a remote, surround bypass if you would like to venture into HT and a host of connections including Balanced ins & outs. Now is the time to buy anyone of the Line models because new editions just came out so the originals, (I have a Line 1), are going dirt cheap brand new. I think you can get them for $1399 new and about $1,000 used. It's really hard to beat at these prices.