There is so much crap, bad information in this thread it is unbelievable. No wonder so many people are just throwing their hands up in the air and buying Astro A50's.
Over the course of the last week I have experimented with each and every possible combination of the following:
Astro A40
Astro A50
MixAmp Pro + Sennheiser G4ME
MixAmp Pro + other PC headsets
The bottom line is this: the Astro's honestly just sound poor in comparison to the Sennheisers. But the Astro's sound wayyyy better than the Sony Golds and any of the other off-the-shelf "gaming" headsets from Tritton and Turtle Beach and the like. You do not need a Schiit Supreme or whatever the hell that thing is called. The MixAmp Pro is more than capable of driving my 600 ohm BeyerD DT880, it can drive your gaming headset of choice.
Here is the MixAmp Pro you want:
http://www.amazon.com/ASTRO-Gaming-MixAmp-Pro-playstation-2/dp/B00NY5ZNZA/ref=sr_1_1?s=electronics&ie=UTF8&qid=1431549586&sr=1-1&keywords=mixamp+pro
Here are the headphones I prefer:
http://www.amazon.com/Sennheiser-G4ME-BLACK-Gaming-Headset/dp/B00KK8ZLEC/ref=sr_1_1?s=electronics&ie=UTF8&qid=1431549611&sr=1-1&keywords=sennheiser+g4me+one
1. If you don't care about talking to people and sounding like a robot:
MixAmp Pro + G4ME One's
PLUS you will need
http://www.amazon.com/StarTech-com-headsets-separate-headphone-microphone/dp/B004SP0WAQ/ref=pd_sim_147_2?ie=UTF8&refRID=0V08Q36ZKPHJJ66T1G0W
You will plug the headphones into the mixamp with this Y-splitter cable and you are good to go.
2. If you DO care about having your voice heard loud and clearly:
MixAmp Pro + G4ME One's
PLUS this same cable as above:
http://www.amazon.com/StarTech-com-headsets-separate-headphone-microphone/dp/B004SP0WAQ/ref=pd_sim_147_2?ie=UTF8&refRID=0V08Q36ZKPHJJ66T1G0W
AND you will need the Turtle Beach "Chat cable" to connect the controller to the MixAmp pro:
http://www.amazon.com/Turtle-PlayStation-Headset-Compatibility-TBS-0276-01-4/dp/B00HS5FETM/ref=sr_1_1?s=electronics&ie=UTF8&qid=1431549515&sr=1-1&keywords=turtle+beach+chat+cable
This video explains the chat issue with the MixAmp Pro and why you need that Turtle Beach cable for good voice quality:
https://www.youtube.com/watch?v=Gd3CxBbrRS8
All this talk about amplifiers and old versions of the MixAmp that you can't get any longer are a huge waste of time. You don't need anything other than what I posted above. Sub in your own headphones if you have other preferences.
if you do NOT care about 5.1 audio I recommend just plugging in some iOs/Android chat-capable headphones like Momentums into the controller and
call it a day. The sound quality is more than acceptable and mic quality is great.
FWIW - I am extremely hesitant to recommend Astro products as there is much evidence they are aware of all the problems with their MixAmp's but do nothing about it. But as far as I know, there are no alternatives to what the MixAmp pro can do for the PS4.