that was an excellent answer! thanks very much more-informed Rich

Could any of you guys either explain or point me to a faq or other resource that explains exatcly how a separate AMP can make a pair of headphones sound better? I mean, I thought an amp "amplified" - made louder. But apparently it also makes for cleaner sound somehow - right? thanks...

In my reading of from the headroom web-site, it seemed to me that there was no performance difference between the two headroom mini amps - just that the more expensive one had slightly more durable parts.... ?

Thanks everyone for you r help! I emailed Sennheiser and they told me to send the phones back (again) to their "headphone repair" department in Old Lyme, CT. So they'll soon be on there way again! Thanks again, Rich

This set is several years old so I suppose its no longer under warranty. I plug them into my airhead headphone amp so I'm using the smaller plug. thanks, Rich

Wow! Smaller and better. Looks like I may be spending more of my already dwindling pay check. Obsessed? .... not me Rich

cool! This is got to be the smallest headphone amp oyut there.. Wonder if it compares withthe airhead for sound quality? thanks, Rich

Look at the portable "airhead" headphone amp from headroom at https://www.headphone.com/layout.php...tID=0010010001 cost: $119 plus shipping. Also - if your looking for an amp for recording studio monitoring - a company named Rolls makes rack mountable headphone amps for around the same...

I have an older set of HD580's and have had problems with them ever since I first purchaed them (from headroom - great source for headphone stuff!) The problem is intermitten connectivity loos - at first it was in the right ear. I thought it was a cable problem but the folks at Sennheiser...