I tried different tubes in mine and it was pretty subtle. Preferred the original GE's (which is the typical result when "taste testing").

It's one of the advantages of saving a little more for a quality brand, especially those originally aimed at commercial/professional use.

Beyerdynamic has every part replaceable and the parts themselves are harder wearing (the pleather pads on my DT770 aren't peeling after 3-4 years, my near 20 yr old DT880 still look mint after a pad and headband change).

It ultimately costs less and is less wasteful than throwing out cheap pairs after a couple of years.

It's ridiculous isn't it? "Mid-Fi" would be a portable BT speaker or an economy car's stereo.

The DAC (Digital/Analog Conversion) component isn't going to make any audible difference. The 32 ohm DT770s still aren't super efficient (impedance alone means nothing) and I have found some devices that can not drive them to adequate listening levels. If you find yourself turning all your digital volumes up most of the way for sensible levels, an external amp or DAC/Amp combo might yield benefits. The big win would be the convenience of an analog volume knob and jack on top of your desk.

You mean the space that loves their In Ear Monitors?

I had a cushion thing like this about 20 years ago. From memory it was kind of silly and the cabling got annoying. I wonder what happened to it.

I've got sonarworks reference - it's great to use as a DAW plugin, not worthwhile for music listening with headphones vs Equaliser APO/Peace and base community EQ profiles IMO.