About 3 weeks ago, I picked up a SMSL Sanskrit 6th Anniversary edition DAC and a (SMSL) VMV VA2 Amp on Amazon for about $210.00 USD. (This price was for the Black version of the VA2 - the Silver edition costs 25% more for some reason). I use this in combination with Senn HD 700 and it sounds really, really good. This amp is a bit warmer than the Schiit Magni 2 Uber imo. I replaced Magni 2 Uber/Modi 2 Uber with this and to my ears it sounds nicer with Senn's, both with the HD 700 and the HD 598. As far as the DAC goes, I cannot tell the difference between the two DAC's and they both have the same functions and I/O's for $43 less. (I need to add the caveat that I believe the Schiit to be better quality for long term and only recommend the SMSL if you are on a tight budget - ALSO the Schiit Modi 2 Multibit 'Mimby' sounds better to me than the SMSL and I am ordering one shortly to replace the Sanskrit, but that is $160 more expensive overall).
As you can read up on HeadFi, Senns tend to run a bit on the bright side and aside from the SS/Tube amp preferences This should be paired with a Warmer amp.
Hope this was not too long winded and helped a bit. I went through the same process about a month ago. Whatever you decide on enjoy the cans!
Cheers!