Sam, some high impedance/low sensitivity phones don't work well with portable players, but the headphone outputs on typical receivers, including your 606, should work well with most, including the two I mentioned. Beware of the hype from some sellers making claims about mysterious sound improvements if you buy the special amplifiers that they sell.

If you're looking to save money, compared to the original amount that you mentioned, give particular attention to the Grado.
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Enjoy the music, not the equipment.