I`ve been looking at getting more battery life out of my D-777 discman. The current 2 x NiMh NH-14WM(A) I use only give me about 4-5 hours. Would sticking in a couple of Li-Ion gum batteries like the ones from Hi MD walkmans blow up my D-777? I think I already know the answer because the...

I use a D-777 Sony discman from the `90s and get exquisite sound out of it. Powerful, detailed and warm. I would like something a little more convenient like a "DAP" and like the look and endorsements of the Sony X series walkman, but only if there is no sacrafice in SQ from what I use now...