I use this amp with the Sennheiser HD 600s. The sound is very clean, with tight bass and a smooth midrange. The Cosmic has a very quick response, making it perfect for music with a wide dynamic range, such as rock. Classical music (especially strings) is uncolored and delivered with a smooth sound. I can listen to music for hours with no hearing fatigue.

You may want to ask Headroom to recommend a pair of RCA cables because the inputs are recessed to protect the cable connection from stress; this is a portable amp after all. Typical "monster" cables may not fit.

Overall, the amp brings out the best in home and portable CD players as well as computer audio sources. It's not really a portable amp, but if you want to run with 4 "D" batteries you can; the battery pack is included. While I can't imagine anyone walking around with a $700 amp, the Cosmic is a versatile performer at home.

Recommended: Yes

Amount Paid (US$): 699