The Sennheiser HD580 headphones are very well regarded in terms of the overall musical quality. If left unamplified though, the overall sound will be less than expected. Like with most Sennheisers, they need to be driven properly otherwise poor audio quality or rather veiled quality will be presented throughout the soundstage. I currently have mostly Chinese made amplifiers with the exception of the Sennheiser BE90, which comes with its own amplifier. The C&C Box+ will help with what you are seeking in terms of boosting the sound. The amplifier features a bass gain, soundstage, and output gain switch, which except for the gain, I do not use. The sound quality matched with the HD650s is rather pleasant and very musical to say the least. The soundstage presentation is very close to many other high-end amplifiers however the price you pay for the every little enhancement adds up. Go and check out C&C's website at
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For the HD580, the C&C F1 may give a more natural soundstage with the ability to keep up with the demands of the headphone. Just a word of caution though with this amp is the fact that due to the size of the unit, it can be easy lost in sea of amplifiers. Check it out if you can. Hope this helps