Looking for a new (preowned OK) line stage under $5K: suggestions?

That's a nice list of goodies.

I would document what you are actually getting with a sound level meter and a test cd with individual frequency bands, then you know how much and which specific frequencies you need to 'tame'.

meter, tripod mount, put it ear level at listening position.

 

I use this Test CD, tracks 9-38 are 1/3rd octave from 25hz to 25k

 

If you cannot find it for a reasonable price, write me a message about it.

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After charting what you are getting, you might find a different location and/or toe-in helps

I'm a big fan of level controls, both my main speakers (electrovoice drivers from 1956) and office (ar-2ax from 1967) have two level controls. Adjust the mid to the woofer, adjust the tweeter to the mid (interactive and l/r together, it ain't easy). Like yours, the quality/character of the sound is determined, only the relative volume is altered. After that, the character of the sound can be altered in small ways as you suggest, but I would not go at it without documenting what's what.

Not sure that colour coding the line stage is the way to go. Have you tried toeing in the speakers to where they cross just in front of your listening position?

I recommend the Lamm LL2.1

Very happy with my line amp, LA-4 from Benchmark, SS design. $2599 which includes a very nice remote and a 30 day trial period, made in upstate NY. Rory is the person you will deal with, Top notch company, Nothing to lose. Robert TN

Zavfino Prima MKII OCC Speaker Cable would probably be a good match for the Pulsars. They seem to be rich in the lower and mid frequencies. In my system it is a little too much (Fyne F 1-8 speakers). 

I second the Rogue RP-7 preamp with NOS tubes. It is what I use, though the rest of my system is very different from yours. I had a Benchmark LA-4 that I sold after trying out the Rogue. The LA-4 is really excellent but it is not going to get you the bloom and richness that you are seeking.