Tube Sound With Equalization?

Well... I think it's worth having one, the Schiit Loki is often recommended.  Try a little boost on the right two dials.

You could try a tube buffer between your amp/preamp.

Don't know what's available now, but maybe look for a used iFi micro iTube2?

I wouldn't recommend the old Musical Fidelity unit (X10D I think), but the 2nd version of the iFi was well received and they pop up occasionally.

DeKay

The tube sound I go after isn’t typically just something to do with frequency response fluctuations, but comes via an enhanced sense of clarity, at least partly from the harmonic structure of the tubes. Not sure how that can be eq’d into the equation minus the tubes.

No a Eq expands the frequency response but a true Vacuum tube preamp is just more expansive ,call it coloration or even harmonic distortion  much it sounds nice to the ear, with many brands ,most brands the critical volume attenuator most use a passive,$20 Alps pot which robs detail especially low level micro detail .  A Resistive ladder ,with relay much much better.I-just Purchased a Linear Tube Audio Micro Zotl  ,it’s a Excellent Vacuum tube preamp. my brother bought one , I had to have one with my Very under the radar BelCanto E1X Amplifier which has a lot of the Black series technologies not any regular class D ,.The LTA preamp for $6350 with excellent sounding tubes and build quality 2nd to none competes with ease anything at 2x+ it’s cost, well worth checking out for added realism in your recordings.

TMR has a Modwright tube buffer used at a decent price. I think it also has balanced inputs.