I'd be willing to spend up to $200 but ideally less than that. I saw there's something that you just plug into the USB port of the computer like the Audioquest Dragonfly. How does something like that compare? Portability isn't really a factor but I guess I'd prefer something that doesn't take...

I plugged my Sennheiser HD-600 headphones into my cheap Dell laptop and the volume was so quiet it became obvious to me I needed an amp. Does anyone have any recommendations? I don't need great quality considering I'm just listening to streaming music anyway, but clearly the headphones aren't...