Since I will not bother recommending something I do not have, I will instead instruct you to take a look at the O2 + SDAC AMP/DAC combo (it's on Drop, don't know when it will be active again). It's $150, so it won't break the bank. It also complements the neutral sound signature of the 58X with its own relatively neutral sound this AMP/DAC produces. You will not be disappointed with it, that is for sure. If you're looking for a more 'fun' (emphasizing lows) AMP/DAC, look for tube ones.