Adding Tone Controls?

You might be a good candidate to try a decent power conditioner on your source gear and/or pre-amp as a first step. Probably can't hurt and only help.

I am not familiar with your digital source gear but assuming that is solid IC changes for a tweak might also help. Try DNM Reson for great top to bottom balance with top notch coherency especially through the upper mids. Or even inexpensive used networked MIT ICs like the Terminator series for a softer sound with more weight in the low end.

Also the no cost toe in/out idea mentioned above is always a worthwhile thing to try before changing anything.

Bama,

HArd to say without hearing, but my gut tells me that there may still some system level tweaking along the lines folks have suggested possible to get the best general performance possible out of you setup.

If it were me, I would exhaust all the possibilities towards that end first to be in the best general position possible before looking to tweak specific recordings or recording types. You could find the need is gone at that point or perhaps greatly reduced at a minimum.

IF there are a lot of recordings of any genre that do not sound good or right, that is usually an indicator that something is still not right in general.

However, the sound of recordings varies widely. If you goal is to merely make them more uniform tweaking the whole system to best effect is not the solution. A flexible or even programmable sound processor of some sort is needed, though I think the extent to which any lesser recording can be made to sound like the best recordings is inherently limited.

Bama,

WHich what are some pop band recordings specifically that you are looking to improve?

Thanks.

"This is what happens when you place music before equipment."

No music without equipment unfortunately.

You might still need digital processing to get what you want out of certain recordings, but best to have the right foundation first. That can go a long way towards enabling more musical enjoyment more easily over the long term, as opposed to spending time tweaking for every less than optimal recording encountered.

Digital equalization might help if treble level is the issue, but it is not clear to me from what has been stated so far that is the issue. Certainly, if the treble is irritating, making for less of it can only probably help, but there could be other reasons why treble is not good. Distortion would be the most likely. BEst to address that if the case. Almarg presented one scenario that might lead to distortion in the treble. Another might be the pairing of the tube pre-amp with the Pass amp. I am not sure the Pass amp is necessarily designed to work best with a tube preamp with <30K input impedance? That could be creating distortion as well that might be reduced with a better pre/amp impedance match perhaps. Nothing against the CJ or Pass gear certainly, just not sure that the pairing is optimal from a distortion perspective. Maybe others can chirp in on that. If both pre-amp/amp impedance matching and Almargs issue identified with the amp/wire/speaker combo were both in play, that could be a double whammy that accounts for what you are hearing.

I have heard similar MLs run off a SS Krell integrated (amp/preamp impedance matching should not be an issue with an integrated amp) and Krell digital source. There was no irritating treble! Quite the opposite! So I am confident that what you are hearing need not be the case with teh right foundation of equipment in place. If it were me I would want to hear your gear with either a better match between tube pre-amp and amp, or with good all SS amplification in place. Then see what recordings sound good or bad and go from there.

Bama, also I am curious how old you are? Younger people in their teens and 20's tend to hear higher frequencies better and are more affected by "bad treble" than their elders, so it is a useful thing to know.

I think the OP has gotten several good and varied suggestions within the realm of possibility to consider.

I'm curious to see how things turn out.