A normal laptop is unfortunately too weak on the chest to drive 250 ohms.
Is that a good little amplifier for a laptop / PC / cell phone that I can use it properly?
Your laptop can do that easily, just don't rip them out completely. After all, my old PC has no problems with the 990 Pro. And I don't have a sound card, at least not more than the one permanently installed on the mainboard.
I don't know any better ones than those in the price range. The 990 are only completely open, the 880 think only half half
Oh yes, they should also be available with a lower ohm number
I gave the KH to my girlfriend and tested it for a few hours / days beforehand.
My comparison is e.g. The 770 80ohm or DT 1990.
I was relatively satisfied with the 880 250ohm as far as I can remember. It's been a while so I don't remember exactly, but there weren't any major points that bothered me.
I would definitely prefer it to the 770 and I remember that I found it very comfortable.
You can even operate them on a good PC, I lent my friend such a small Fiio amplifier so that she can definitely use the headphones (which, by the way, I haven't seen again so far). Of course not the best DAC / AMP combo, but I can actually recommend the one I had for the price. Was the e10k or something, but there's a newer version and Fiio also has such small amplifiers for cell phones.
However, this should be operated with a correspondingly powerful headphone amplifier.
The DT880 is basically a good headphone without significant technical weaknesses, with good repairability and the best sounding ex works from Beyerdynamic (not that that means much, overall rather brightly tuned with sometimes sensitive highs). If you like the sound, the only counter-argument is the low sensitivity (250Z with 100dB / V and 600Z with 96dB / V).
You can't go wrong for the price, but it's not that there isn't any competition. The best all-rounder under 200 euro would be the new Sennheiser HD 560S, but the new HiFiMAN HE-400i 2020 and 400SE, the AKG K612 Pro (and the somewhat less harmoniously tuned K702) and of course the Philips X2HR are also attractive. It's definitely worth comparing.