How revealing are Grado sr-60s'?

I just bought a pair of these last month and overall they seem like decent headphones, but im still having problems with the overall sound of my system. I dont know if its the phones, or my electronics but im getting a somewhat bright, grainy sound. Electric guitars seem way too thin and dont flow smoothly enough ( cant think of the correct term).The bass seems sort of weak too, with a focus on treble. My amp is an Onkyo TX-8511 and a Toshiba SD-3950. My gear is not high end by any means, but do i really have to buy a $500 cdp and headphone amp to get good sound out of $70 headphones?