Adding Tone Controls?

From yr description the offensive recordings suffer from "sibilance" (~6-9kHz).

Unfortunately, unless you use an equalizer, there is little else you can do to correct this situation. This is a unit placed between your source & the amp (or amp->speakers)

BUT active equalizers are typically abysmal sounding and do more harm to the sound than good -- bar a few outrageously expensive ones.
Generally speaking using one is like shooting yself in the foot given your efforts to put together a nicely balanced, great sounding system.

One patch solution is to use zip cable as an equalizer: these cables typically lose high frequency response and may tame the sibilance.

Oh for heaven's sake, he's already listening to abysmally recorded albums and you're gonna worry about the supposedly deleterious effects of an equalizer? Some times I wonder if some of you guys made it thru grade school.

Buy a decent parametric equalizer, should be about 200-300 bucks and then dial back the offending frequencies when listening to such albums. When you're listening to "audiophile-approved" recordings, simply switch the EQ out of the signal path...

-RW-

There is absolutely no valid reason not to use an equalizer, or a set of tone controls, IF you put it in the tape loop of your pre-amp. Judging by the effort you have already made to get quality sound, I think you would be disappointed if you just put it between your amp and pre-amp. It will affect the quality of the sound you have and be a PITA to use all of the time as you went from one type of redcording to another.

Another possible solution - get an inexpensive tubed DAC or CDP - then find tubes that will give you a very warm sound. That helps a lot and you can keep it cheap if you're careful.

But on the whole I would use an equalizer in the tape loop.