This is not about to blowing your ears.. Grado has is low impedance drivers. Therefore to scale linearly all frequencies wtih volume increase, the amp have to have good current reserve. And some grado (like GS1000) are more sensitive to this. To explain it better.. if amp can not deliver enough current, it will strongly distort bass when volume goes up. So when volume is low.. you hear it well, going up.. you can easly hear how bass is going to be distorded and the sound getting really bad.. just highs and mids in your face. But when amp is good for grado, then you can go really loud, but what is nice you don't even feel that this is loud.. it just very open and nicely sounding. I don't know how to explain better. Maybe someone with engineer background can help. But what i learn for example if takin valvolar amp. FOr grado it hase to be with transformer in output. There is schemes where big capacitors used instead to reduce size.. this not good for grado nad fail in my case. Mad ear +HD fits very well. A SS Bryston BHA-1 is also good. And when ppl sayng Grado is easy driving.. is true in a way. When volum is low, you already can nicely enjoy their magic. And if it's scale well with volume increase, then you understand what all this about. And exactly this require good amp.