Hi, I have a Sony CDP-228ESD and I currently listen with headphones only, Grado SR60. I was wondering if the headphone socket on the cdp is as good a quality as the rest of the cdp or would I get a decent improvement using an external amplifier? I do have a set of Kef Crest 1's spare and would link these to the amp for occasional listen but would consider just a headphone dac/amp if the improvement would be considerable. Don't have loads to spend so would probably trawl eBay for an amp from the same era as the cdp and I do like Sony products. Any advice appreciated.