High end stereo preamps? Worth it?

I don't think you need a preamp in a digital/streaming system.  You just need an attenuuator to "pre-attenuate" the signal.  If you want the best attenuation, the Benchmark LA4 is about as clean and transparent as it gets.

That said, if you try several linestages, you may find one that produces a deep emotional response when you hear music played through it.  But I don't think money relates directly to finding that magic, or that the linestage is objectively better than others.  It's all experiential.

In my case, it was a Modwright 36.5 with a NOS Mullard in the power supply.  Loved it in the first fifteen seconds and ever since.  Wouldn't let it go. More distortion? I'll trump that objective card with pure pleasure and a smile of musical bliss.

George,

I was trying to make a point with extremes. A point which you can substitute your favorite amp in place of the Lamms. The thrust of my argument, I believe, will still hold true. 
No one can argue your perception or argue how any piece of equipment makes you feel.  But, with respect to the example I’ve chosen, the Lamm SETs, it’s really not fair to discount what a great majority of reviewers, reviewers who are paid to review gear, have said about a unit publicly and in major journals. You certainly are free to disagree about their opinions, but still...

Best,

b

Just asked for the link/s to "your claim" that 

  that the vast majority of professional reviewers regard (the Lams) as among the very best sounding amplifiers on the planet.

That's all.

Cheers George

Not going to dig out the references, but I used the Lamms as an example bc reviewers in Absolute Sound, Stereophile, and several other journals have said it—repeatedly—about every iteration of the Lamm SET products. I chose the Lamm example bc they have relatively high THD graphs and pros said they sound better than pretty much everything else out there. 

Benchmark LA4  Line stage device sounds interesting to simplify whatever a stereo preamp does.   For streaming only, seems ideal and wonder about amp matching issues.
Wish it came with a ht bypass.