My sacrilegeous question to audiophiles out there regarding parametric equalizer.

Nothing wrong with it at all. Only the purists here think of it as sacrilegious.

I’m afraid you misunderstood my post, maybe you should re-read it. I never said nor did I assert that components are equalizers. I said “tone controls” which was in response to your pretentious statement “my el34 amplifier has no tone controls”

You have heard about tube rolling no? Do you not think  tubes are altering the tone professor? Or do you think all tubes sound the same? Of course not that’s why you prefer vintage Dutch and British tubes, you like the way they sound.

You then go on to say “The amplifier, tubes etc are just reproducing the sound that has already been equalized”. Are you trying to say amps and tubes have no effect on the sound?

I especially like your blanket recommendation to just get some vintage small signal tubes and you wont need tone controls (thats exactly what they are). How do you know this? How do you know what sound the OP is looking for? What do you know about his room? Is it treated? How are his speakers are set up? Where Is his listening position in the room? Poor first reflections or standing bass modes (if this is the case) will not be solved by your magic tubes.

If the op cannot afford room treatments or change the way he has his system configured than perhaps some dsp could help solve some of his issues. But you were being to pompous and condescending to ask any questions.

@tubelvr1
To get back to your original question, it seems unlikely that an external analogue equalizer will enhance detail—if anything, it might actually reduce it, which is what happened to me when I tried it years ago.This is because you are introducing an additional circuit — and some distortion — into the reproduction chain; also, you know that you cannot enhance what is not there, you can only reduce the remaining elements to forge a new sonic balance if you will. There are extreme analogue equalisers out there, of course (FM acoustics comes to mind), but these come at equally extreme prices!
All of this differs from what other posters above are discussing, i.e. the merits of changing components in a specific circuit, like tube rolling, for example—that you could try, if you’re using tubes that is.

Or, you could just different speaker placement - closer to the front wall could enhance bass while further apart and away from the wall may enhance detail & soundstage because bass notes will be less pronounced, bringing the mids & highs into the forefront...

Normally in High-End home system we don't need an EQs, because everything is just great. The shortest signal path is the way to go. However, we change cartridges, tonearms, cables, amps, preamps to find what's the best. 

But for professional application EQ can help to quickly adjust the sound in a certain room such as a bar, club or whatever place where people playing records in public. In such places you need to quickly adjust everything, this is a compromise. Some public places are terrible in terms of room acoustics and the EQing sometimes can help. So in my opinion EQ is for professionals, not for Audiophiles. 

However, i rebember all those Hi-Fi home systems from the 80's with EQ and it was fun to play with it, i've been using EQs when i listeted to cassette tapes as a teenager. 

EQ in Audiophile's home is like too much spices in the good food.