You would be better served by Sennheiser HD-25-II pros.
Would I benefit from a headphone amp?
I have a TOTL Sony D6C cassette walkman and Grado 325 Headphones. Could a headphone amp worthwhile enhance this combo? It sounds wonderful as is but Im greedy for more. Is the headphone amp in the Sony of a good quality that I would only hear a marginal difference? Also there is one output and input. Can I use a split cable and get stereo sound? Thanks