recently purchased some dt990's 600 ohm.. amp recommendations?

alright ive actually spent a lot lately and planned to end it at the dt990's for a while. i have the audio gd NFB-12 Dac/amp combo and apparently its rated for 150mW at 600 ohms. idk if thats enough to get the full potential from these cans?

hmm so far all i can say is very clear given good files, but somewhat cold for my taste. i feel like a tube amp would greatly benefit these by adding some color to them.  I might check out a little dot in the future, but for now im having fun messing around with my eq on these. the program i prefer is jet audio plus, foobar 2k is sweet but just too flat sounding for my liking. however i have noticed these headphones do not sound better eq'd like my aktimate mini bookshelf speakers. minimal eq on these is best. toning down the treble a tad helps but id really like to see what the sound like through some tubes. oh and the nfb-12 drives them plenty loud enough. theyre loud enough for me without even getting to 12 o'clock

edit: Oh i forgot to mention i REALLY like the bass on these cans. it holds tight wayy down low. something i was really looking for. honestly i think any less bass such as the dt880's might be too little. although i cant comment since i havent tried them. yet.

alright i got my eq settings perfect, looks like a W with a big hump in the middle. really balances the vocals with everything else. yes i might have to try a tube amp then to try and round out the highs. god three hours in now that im used to the sound im adoring these headphones with the nfb-12. so clear but not boring in the least. id hold on to your 880/600's though from what i hear they sound even better than the 990's, i just couldnt find a pair for the price i was looking for.

slightly, nfb-12 using the woflson dac chip helps a bit, which i find to be a tad warmer than other sources. but no eq'ing can replicate a tube amp honestly.  Ive never owned one but heard them plenty of times. seems like it'll be the final piece to complete this rig (which already seems like it cant get better at this point)

yes haha just keep in mind this is all my ears. and im used to warmm sound so im biased in that aspect, but these are great headphones, and for the price its hard to beat the nfb-12 for what you get. i say go for it man! you wont be disappointed for the money