I am looking for a reasonably headamp with a Dac with an optical input

The Magni is just an amp without a DAC and not sure if Schiit sells a DAC/Amp with an optical input.  Go to Drop.com and look at the Xduoo XD-05 Plus for $210.  It also has a battery so can be portable if that’s ever needed.  Also on Drop, and if you can stretch to $425, the Aurender Flow is even better if it has enough power for your ‘phones.  Hope this helps, and best of luck in your search. 

The Modi has all three most common inputs easily switchable. I wouldn't buy anything from Drop. Anymore. I bought a Xduoo amp they said would ship in a month elsewhere. I got it, same price < a week. With an actual warrantee.
Magi/Modi is $198, less for B-stock. Made in USA.

+1 @fuzztone re: Drop these days.  In fact, I just cancelled an order for some Sennheiser ‘phones from them because they delayed my delivery after already having waited three weeks for the damn things, and I ended up getting them for the same price direct from Sennheiser in only two days!  Argh.  The reason I recommended them here is because the XD-05 Plus is $50 cheaper at Drop and you seem to be price sensitive.