I'm going to keep this review brief and to the point. This amp is freakin' awesome for $250 and it has a high/low gain meaning it's capable with almost any type of headphone you can throw at it besides orthos. I use it with my DT880s and they sound way more fun and not boring like they used to. So ya, just buy this amp. There is no transformer hum and the noise floor is very low. So disregard earlier reviews because some of the first units produced were defective. Best $250 I've spent in the past few years. BUY IT

I've owned these cans over 2 years and I've watched them mature like fine wine sitting in the barrel. When I first bought them I was surprisingly disappointed. I was expecting a lot more but found their sound to be tinny and weak. After many many many hours of burn in these cans really warmed up and showed coloration in a nice way. I like to compare these headphones to my DT880 600ohm cans for reference of sound. These cans are much more LIVELY while my DT800's are more ANALYTICAL and neutral. I would say the HD280s are much more suited to electronic/hip hop/ dubstep and any sort of bass heavy music that doesn't require a soundstage. I found my DT880s much better for rock/jazz/some electronic(progressive house) and a few other genres that require a large soundstage such as live performances and movies.
 
Overall, the HD280s take a long long time to burn in. I suggest burning them in for atleast 200 hours to see the full potential of them. These cans are an amazing steal and have incredible bass response for their price tag. My source right now is an HT Omega Claro 24-bit/192khz DAC to a Schiit Magni amp which sounds absolutely amazing. I prefer my HD280s for reggae and hip hop over my DT880s but would pick the DT880s for just about every other genre of music.
 
Here's the bottom line: let these cans mature and then they will put a WOW on  your face. I have compared the bass of these cans(500 hours burned in) to the Ultrasone Pro 900s my friend owns and I must say these can hold sub-bass frequencies surprisingly well while sitting next to the bass king Ultrasones which still reigned supreme over the HD280s.
 
For $99, I purchased them at discounted price for $78 I must say they are a complete STEAL. BUY THEM! NOW! If you have money to splurge I suggest you get the Ultrasone Pro 900s as they will crave your desire for BASS