Hello Head-Fi! I purchased an iBasso D4 Mamba portable amp/dac almost a decade ago after reading about it on these forums. I got them to power my Sennheiser HD650 when I thought that I would need a portable amp/dac. Turns out I really don't, and I've been wondering whether it's worth a maximum budget of about a $100 to buy a new desktop amp (and/or dac) to pump out better quality from my HD650s. I have no idea how the D4 Mamba stacks up against more modern amps and whether it's any good of a device in the first place. It certainly wasn't cheap when I bought it. Should I ditch it for a max $100 amp (and dac?) and expect a better show from my HD650s? Advice much appreciated!