A Birthday Gift for my Sennheiser HD 800s

[GREATESTBOSS]

Hi Everyone,
Just got promoted and my Birthday is coming up soon, So I’d like to treat myself with a new Amp.
I've just bought a Sennheiser HD 800s Headphones and I'm looking for an Amp to pair it with. Please note the following before answering my question.
1- I have a Marantz Cinema 30 AV Receiver supposedly a top-of-the-line unit that has a built-in DAC.
2- I will mainly use the Headphones for 80% Watching Movies, Football, Sports & 20% for Music " Heavy Metal, Rock and Movies Soundtracks".

My Question, 
1- Which Amp do you recommend to connect to my Marantz Cinema 30 and my Sennheiser HD 800s Headphones?
2- Is the DAC in the Marantz sufficient or I will need a separate DAC?

I don't want to pay over the odds, yet I want one that has the power to handle the Marantz and Sennheiser and blend well together. 

Kind regards
 
 

[TMoney]

ECP audio/Nitsch and our own @dsavitsk is your man. His stuff has been bullet-proof for me and sounds so good I haven’t been remotely tempted to upgrade since.