Thanks for the reply. That particular amp seems hard to get here in Germany, I'll see what else ebay has. For now I'm waiting for the headphones to arrive and see how they fare. When I was saying the Sennheisers sound muffled, it's more of a general quality of theirs - they were kind of distant...

Hey guys. After careful consideration I settled on these headphones, now I'm wondering if my ancient Sony TA-313 amp will do them justice. While it says "low and high impedance headphones", this amp is at least 30 years old and my technical expertise is just enough to know not to lick cables...