A decent amp can definitely brings out the bass of the THX00. Making it loud does not mean you unlocked the full potential of THX00
Not to mention a good DAC can bring out the best in the TH-X00. Both Chord Mojo and my 90's Theta R2R DAC w/ time-domain megaburrito filter do just that.
The TH-X00 loses some of its spaciousness and separation when I try my Fiio DAP or a lesser delta-sigma DAC w/ a cheap-o digital filter.
IMO the order of of the chain that I think matters most in my own personal experiences would go: 1. Headphones 2. DAC 3. Amp .. I think the suggested differences in amping are highly exaggerated an I never noticed a huge swing in performance by moving to a better amp versus a better DAC.
If you are getting adequate power and your amp shows good measurements in noise floor and THD then really that is all you need. Planars and high impedance cans like the HD800 are the types of headphones that really benefit off of TOTL amps since they have the ability to use that power (e.g. HE-6, Abyss, HD800/T1).
But when we are talking about a low impedance can with very efficient drivers like the TH-X00, I notice the qualities of the DAC more than the amp. The TH-X00 sounds noticeably inferior out of my Sansa Clip+ but I can attribute those problems mostly due to the DAC and noisy signal coming out of such a mediocre device that uses opamps.. but when that mediocre device is paired with mediocre (yet good) sounding earbuds like the $20 Sony MDR-EX100ip then they pair together magically. The sound is warm and listenable yet at the same time not revealing enough to be able to tell that the Sansa Clip has an inferior DAC to anything I have heard that is R2R or the brand new Chord Mojo. The TH-X00 makes the Sansa Clip sound like crap once you go back and forth between a desktop setup. Otherwise your ears adjust and you live in ignorant bliss
I have also heard a fair share of ESS Sabre DACs and they always sound technically capable but not accurate in the ability to stimulate my subconscious feeling that I am hearing natural sound. They are always detailed to a fault. The high frequency details are more of a hiss than a textural and palpable instrument being played with proper decay.
Sorry for ranting, I went on about how amps make less of a difference to me than DACs with the TH-X00. The HD600 is the opposite story though for me. Amping is everything.