Hi, I have a question: why does a buffer improve SQ when connected between a phone and an old integrated amp? Here's the situation: needed an extra stereo setup, low budget, had a Pioneer A-66 X, bought a pair of speakers. When connected to an audio interface - sounds great, connected to a phone - sounds dull, connected the phone to a DIY preamp with a single opamp to the amp - sounds great. Don't bash the phone, when connected to a pair of decent modern active speakers it sounds great. Also, I don't have money currently for and extra player/DAC so going to have to wait a bit. I'm well aware that the phone is optimized for low impedance headphones, but I always thought that the high resistance of the amp input would be even better. Also, why my active speakers don't suffer from that? Is there anyone here with electrical knowledge here to answer these? Thanks!