Please compare the following headphones

Craig-I have the 600's with Moon Audio Blue Dragon cable and a ASL MG DT OTL Mk3 amp set up. I have used Grado 325, 325i, AKG 501 and HD650's all with this set up. I actually prefer the 600's to all of them. The 600 and 650's are not that much different. Although I have not heard the AKG 240/271 Studio's or Senn 280 pro you are asking about...I think they are probably not in the same league as the 600 series as you mention.

The AKG 501 is a nice sounding phone...it falls way short of the Senn's bass though, but is nicely transparent in the mids. It lacks the impact of the 600/650 or the Grado 325 series.

Its hard to beat the Senn 600 especially for the price and it mates well with the ASL. Run in OTL it gives a nice bloom to the sound.

Craig-

I found a pair of Sony MDR-SA 3000's on ebay. The list is $350, but can be had new for about 175.00 on ebay at times. This is a really good sounding phone to my ears. I like them more than the AKG 501's I had and the Grado 325's. I still like the Senn 600 for the smoother mids and fuller bass, especially at low levels...but, the MDR SA 3000 has the refinement and definition of the 600's... better dynamic drive than the 600 without the forwardness of the Grado's. Bass fall's a bit short of the Senn,( hard to beat the Senns here for full bass response) but the 3000 has better integration and bass tone and are more transparent. I have been listening to them for about a week now and haven't had the desire to rush back to the 600.You will still want an amp with these. They are very comfortable also.

Keep us posted on what phones you ultimately get.;)