Need recommendations for a stereo EQ

Schiit makes inexpensive and competent 4 and 6 band equalizers. The Lokius 6 band cost about $300. It's quite transparent but I'd tuck it into a tape loop and your good to go. I do. 

Any of the Loki’s will work. The more settings you have, the easier it is to get lost 

Good luck finding a tape loop nowadaze.

Do you have a tape loop or processor loop? That’s the best way to have optional use of something, compare the changes. You need to keep the volume equal for comparison, perhaps a piece of tape with pencil marks.

Then I would start with an inexpensive multi-band eq, ascertain the changes that you prefer, that will give you info, then, move to a ’better’ unit???

I just recommended this inexpensive unit from Amazon, you can try it, learn something, keep or return it

https://www.amazon.com/Rockville-REQ42-B-Equalizer-Spectrum-Analyzer/dp/B00LZDSL7U/ref=asc_df_B00LZDSL7U/?tag=hyprod-20&linkCode=df0&hvadid=312069187648&hvpos=&hvnetw=g&hvrand=13668772867094839483&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9003512&hvtargid=pla-570384384433&th=1

BTW, years ago, I learned, it is a mistake to seek 'ruler flat' with an equalizer, just mess with it until you start learning what sounds to your liking, then work hard at refining those particular changes.

Just hooked up my new Schiit Lokius. Very happy.   My room is a little bright and needs just a gentle high end roll off, plus I use the 20 Hz band as the bass blocker to my main speakers ( bookshelves) to clean up when I really crank on them. 

I run an Antimode Cinema in line with my sub for a little DSP where it can help without hurting.  Quite happy with it.  ( includes a mic and does automatic setup) . Knocks down a couple peaks which is about all we can hope for. 

To just try things cheap, the JDS Subjective is similar to built in tone controls, 3 band, Mid-grade op amps.  $99  Don't laugh at it because it is not a boutique mega-buck in a billet case with dealer markups and big audio show budgets.  It is what should be built into any pre or integrated amp but the  subjective reviewers with nothing else to do convinced the "esoteric" market they are evil so they went away along with balance and loudness, rumble filters and other actual useful features.  Bitch, bitch bitch.  

 Lokius is a big step up. It uses tanks, not op-amps.  Without going DSP, there are not many other options that can even get close to good mid-fi, let alone what your AR/VT stuff provides.  They do have a trial-return period so very low risk. 

All these have bypass switches so they don't need a tape loop like in the old days. Just put it between the pre and amp. 

Dear @cabkab  :  There are different type of eq. as graphic or band ones  and a blend of it and you need to read information about to look what you need and from different manufacturers which kind of parts devices they use to make the job.

Here is a good explanation on graphic eq. and in the shiit site for band eq.:

https://www.ranecommercial.com/legacy/note101.html

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.