Grados will probably sound bad through that receiver.

The headphones will make the most extreme change in sound. But it is the source which will affect the overall enjoyment of it.

The best thing to do is take both players to the next meet and compare them to what others have there. If they find the sound acceptable using their amp and headphones then chances are that you can trust them to steer you right.

You may want to play around with ICs and choose one that is smoother, warmer, etc. But there is only so much that they can do; what they can do is tame any sibilance if in fact it is the cable that is causing the problem.

So you could either spend about $250 for a dedicated headphone amp which may or may not mate well with your present or future headphone or just get another headphone and change the whole character. Either would be a good choice, but you may feel that even with the best headphone amp the HD590 still sounds sibilant.

At the meet check out other players with your headphones. IF the headphones still exhibit the same propensity then get new headphones.

For a short term fix: get a new source. (Just make it the best you can get at the present time).
For an immediate fix: get a new amp.
For a long term fix: get a new headphone.

When can you attend a meet?

That sounds strange. The specification may be a rating representing the type of load that should be received by the headphone jack output, or a measure of the output, rather than the actual output impedence of the headphone jack, or something of that nature -- I'm not technically minded enough to decipher it, but I know there are a few head-fi lurkers here and there who are very fluent in such things.

I've never heard of a 560 ohm headphone jack. I doubt that's what it means, but if you do indeed have a 560 ohm headphone jack, a headphone amplifier may make a nice addition to your setup. A chance for me to learn something new if someone knows how to interpret that spec.

Quote:

GanChan,
for the largest improvment in sound, i would invest in a really nice (as nice as your wallet can afford) cd player. not only will your headphones improve, but your speakers as well will also improve. you can get an extremely warm, rich sounding cd player by buying a used Rega Planet 2000. it is a little pricey at around 500$ (used), but it is always refered to around here as the most analog-like sounding cd player out there. in other words, it matches most Senns really well. i run my Cosmic and Senn HD650's out of the Rega and it is a match made in heaven! btw, the 650's, if you can afford them, is the best choice for upgrading your headphones based on what type of sound you say you would like. so, with the right source, you can influence the sound in a very big way. that seems like the best way to get the most out of your money relative the amount of changes you will notice.

an equal amount of change would probably take place with some new headphones...but you wouldn't have the benefit of changing the sound in both your headohones and speakers. if you like a warmer sound, i'd definitely go for, or at least try out, the Senn HD580's, which can now be had for approx as low as 100$ (used). while i'm on the subject, i strongly recommend buying used. you simply get more bang for your buck. buying used allowed me to get a better quality amp (the HR Cosmic over a lower priced HR model). i would never be able to afford a new HR Cosmic. good luck with your search. and take your time in making a decision. it is very imprtant to do the research, especially when you don't have any other option other than buying blind online. let us know how it turns out with some detailed impressions.