I have a Heddphone arriving tomorrow, and going to try it on several amps. I have an SMSL SP200, SP400, SH-9, plus the Topping A90 discrete and L30 II and will see which does the best on it. Just for kicks I'm going to try it on this Soundblaster X1 using an adapter. It did power the DT880 600 ohm pretty loud, but no headroom for EQ at all. I'll use the Topping E50 DAC as a baseline to keep it consistent for the amplifiers. It's amp-a-palooza this week, so good timing on these arriving today.
Update, it arrived and much easier to drive than I was expecting. The Topping L30 II is at 12 oclock on high gain and I wouldn't want to go louder for any length of time. The SP400/M400 combo sounds the best to bring out bass dynamics and treble a little more (or less warm to say another way). The sound reminds me most of the Hifiman He6se after equalizing it, but without the ordeal of powering them loud with a -4 or -6db preamp reduction. I quickly learned why people use banana clips on a speaker amp with those. The A90 discreet is excellent on the balanced side with tons of power, you'll never leave medium gain with an XLR DAC like the E50.
It's smooth and refined, but not too warm or rolled off in the treble region. The treble isn't as rolled off as a Focal Elegia, but it's getting there. Pre-volume war recordings and replaygain will need more power than the L30 II has to offer, but out of the box it's ok. If you get a pair of these and hear foam rustling when you put them on, wear them 5 minutes and the memory foam warms up and they're silent. These are heavy, but not if you're used to wearing a bike or motorcycle helmet for hours, no problem. Just tried them on the SMSL SP200 that was plugged in anyway, 50 percent in high gain and I wouldn't go further. Going to spend the day mixing and matching stuff on these...