Help with

I recently did some upgrades to my front end (source) resulting in incredible improvements for my mid-fi system, but with added brigthness... that is a tad too much. So let me explain. Before upgrade, my system consisted of CAL Audio DX-1 CD player, Adcom GFP 565 pre, Rotel 980BX power, and NHT super ones w/sub. Straightwire midgrade interconnects and Kimber 4TC speaker cables. The system was quite warm, but lacking air and transparency.
I upgraded to Creek OBH-14 DAC and Pre, removing the Adcom from the chain and the CAL DX-1 became a transport (Canare Digiflex Gold cable). Incredible inprovement! But after about 2 weeks my ears started to hurt. Jitter it must be, and I got myself a Monarchy Audio SuperDIP here on Audiogon. Whow even better sound and a tad less bright.. but the "too bright" feeling is still there.
So, is it the Rotel amp? The Creek DAC/PRE got a very good review in Stereophile.. for being "no nothin''cept good clean sound." To clean and exposes the Rotel maybe? Or do I need other tweaks such a power line conditioner? Any advise? Your help is much appreciated.
This is not an easy one to answer. Let me break it down into general terms--which may or may not be applicable to your system--it's almost impossible to know.

Brightness can be caused by a variety of things, the problem is that not all of those things are bad. Sometimes brightness is a result of having a higher resolution system. Sometimes a prior component may have actually been "dull", or rolled off in the frequency extremes. Then you upgrade, to find a sound that is not as pleasing. This of course ties into system synergy, but I'm going to turn this response into an area that I know very well--acoustics.

Acoustics play a huge roll in the overall sound of a system, bright or bloated in the bass, most of the problems come from the room interaction. It is possible you did improve the quality of your components only to discover shortcomings in the room--not really that surprising--it happens all the time. Unfortunately, many people will say use "xyz" interconnects to tame the high frequency, or "abc" power cord to mellow the sound. These things do make a difference, but I don't think they should be tone controls.

On the other hand, there is quite a lot of equipment that is very good, but some lean towards the lean sound. That's okay, but if you have 3 pieces of equipment that lean towards the lean and bright sound--well, you can figure out what the result will be. This is an important part about system synergy. In the perfect world, everything we would be neutral, but we know that isn't true.

Now, I'll go back to the room issue. Have you measured the room response? This can be done easily and cheaply (it can be done expensively too--but you can start with a basic test CD and meter and get some reasonable results). This will just let you know if the frequency response is relatively flat. You may need to add some absorption to get a flatter response. Absorption at the first reflection points is generally a good idea to tame the brightness.

If you haven't already evalutated the room and some basic acoustics, I would start here. It will make all the changes down the road far more meaningful.
I second Rives on his post and want to introduce the second area that's not well understood: power. You have no noise control/power stability measures. Now that your system is more resolving you are very apt to reproduce HF glare better than before! This will tend to sound bright and present a forward, aggressive & artificial soundstage in the treble region. Not good.

Room acoustics and power delivery are the most important aspects in an audio/video system.
If I recall correctly the Creek volume control is passive and just attenuates the signal from the DAC section to your amp. You should review all of the requirements of successfully using a passive amp to make sure you're set up properly. This has been discussed at length in this forum in recent months. Also, I think you may be missing the warmth thats usually a built in benefit of the Cal Dac's which may have compensated some for the tendency of some of your other components may have to sound a tad bright. While I agree for the most part with Rives, I part with him re room treatment recommendations as a solution at this point in time as you did not have these problems before(although this would be money well spent in the long run as it would/should apply to any most any system you get). I would rethink my DAC/Pre amp and amp/speaker requirements and spend my money in that area before buying cables or interconnects or making great changes in the room. One thing you can try that takes a minute and costs zip - try changing the toe in of your speakers slightly moving the axis of the speaker away being pointed at the ear. If they are already pointed straight ahead, try moving them to cross well in front of you. It can work with some speakers that have fairly flat horizontal dispersion characteristics in the midrange/tweeter. Toed in can also help with side wall reflections.
Thank you all!
Newbee, I think you are right on. My listening room is 27x18 and speakers are far from sidewalls. And the speakers are indeed toed in quite a bit.. I will experiment with pointing them straight ahead. Another issue that I didn't mention, ear level in the listening area is somewhat below the tweeters, the stands for the SuperOnes are a bit higher than recommended. Could that be a factor?
I don't think having your spks. positioned too high will result in brighter sound since the tweeter is above ear-level. How is your 4TC terminated? You might try connecting your amp/spk. bare wire. This might smooth out the sound and refine the top-end. Lastly, you might consider changing the 4TC to a heavier guage wire.(8VS?) Hope you get the results you're looking for! Bill
I would say that Rives partially right but hey what if there is no room and only headphones and still bright?

I enjoy my setup even when I'm not in the seet-spot and even when I'm aside of my speakers and It doesn't sound bright or dull from any listening position.

I agree with Newbee that you should check your passive pre/DAC/amp integrity and that's probably what mainly causing fatigue and excessive brightness.