Help. System sounds thin and bright or harsh

Interesting. Definitely thinking speaker change.( bigger warmer) For sure front end change new dac and new preamp, perhaps a Benchmark HPA 4. Not much to look at (who cares) but great reviews.  Tired of the system dictating the type of music I play.  Contacted Modwright and found out that the Oppo BDP 105 had 8 firmware updates. I never did any of them. Am going to try to get that done via ethernet but am not expecting a big change in sound.

I also have a Modwright tube modded OPPO 105D and I have tried numerous tube combinations seeking to tame the harshness I was experiencing. After trying numerous tubes including the tubes recommended by Modwright I settled on Sylvania 6sn gtb 1950's era tubes. Much of my tube search was to attempt to tame the harshness and shrill quality of much of the upper range frequencies being produced. Yours complaint sounds like much of the same issues I was trying to resolve. I recently bought Modwirght's new "Analog Bridge" and I find that the Sylvania tubes also work well in this installation. Brent Jessee (sp.) has the tubes I am speaking about in stock and he was quite decent to deal with.  

Try plugging your amp straight into the wall with the after market cord you were previously using. Plugging the amp into a power conditioner was a big no non which you realize now.

from my humble experience and I wrote this under this and other posts:

subs won't make it warmer.

Good speakers like the Harbeths are not NOT warm. 

That's the amp's job. I definitely wouldn't sell the Harbeths if your problem is lack of warmth  (sound too thin, too bright). In my very uneducated view, that path won't lead you where you want to be.  I had a 45 year old Marantz,  it had the warmest, smoothest sound with any sets of my speakers. I would try a cheap-ish integrated amp first. 

pmiller115      that's the first I've ever heard from someone having the same front end and the same problem. Been thinking for a few years the front end might be the glaring issue.  Incidentally I got the latest firmware update for the bpd 105 and it did nothing for the sound. Using it straight to the amp is still ridiculously unacceptable,  Tube change offs the edginess only slightly, No bloom no weight to the music/  I have a decent listening room now and the system sounds horrible the more I examine it.....use hi volume to try and bring it to life. Thin and hashy is all I hear.

Jond   I went back to the stock cord for the Pass into the wall as I felt the after market power chord  into the wall also added some glare.  Still sounds horrible,

Grislybutter  gonna have to try speakers and a "lesser" amp to see what is going on here.  Could be a combo of bright front end and speakers that are too small.