I've had these cans for quite a while

the only thing that displaced them out of my regular listening rotation was the Stax Lambda Pro. but considering that this is an electrostatic headphone at nearly double the price of the Beyer, the DT880/600 ohms would be impressive at what it can deliver at that price point

I pair mine with the Audio-GD C-2C. It sounds good because the amp tends to boost the low end, which is complementary to these cans. I do have to try them with a bigger, more robust amp in the future...
for my ears, the DT880 is a winner because:
1) the clarity is very impressive - the HD650 sounds "noisier" by comparison, and the HD650 is already up there in the realm of legends...
2) the soundstage is generous - I have been addicted to this aspect that cans provide; that expansive space which draws you to the music. this can gives it in spades

3) comfort is superb - why Grado chooses their uncomfortable design is beyond me. maybe they are selling millions of those. but these don't turn any portion of my ear raw from hours of listening. and headphones this expensive should be worn as long as they can be...
4) the tone is right - very subjective aspect. it just gives me the best tone among my dynamics. the mids are just a tad recessed but I can't live with the Grado compromise

I mean, this was the king before the Tesla came. and at this price point, I do not see why people are not appreciating these cans, or even Beyer products in general. They aren't portable for a good reason; they need a powerful and beefy amp for a good reason -- because they are supposed to deliver true audiophile quality music. in fact, Beyerdynamic gave them flagship status with their name and reputation at stake at that time. given this consideration, it would really be arguably foolish to pair them up with a cellular phone as DAC or a portable amp -- they were just not designed for that...
the orthos and magnetic planar cans have arrived and conquered the scene nowadays. iems that can compete directly with the sound quality of flagships have emerged. but just look at the prices of those items! these cans are available for a pittance compared to those, and yet they don't get as much attention. but the sound quality of these Beyers can compete with the best of them, at a much lower price. there might be compromises here and there but it's nice to listen to music while not having to starve for a month

well, I still have my DT880. Beyer makes good products. have a listen guys, you might get surprised
