Pass Labs versus Jeff Rowland, Audio Research

I know that this thread is old and that nobody might read it, but Jeff Rowland Model 201s and 501s are not using the old B&O chipset. I have talked with a guy named Rich at Jeff Rowland and asked him this question before I bought the 501s. He said it is nothing like the B&O chipset. He said that the B&O setup was rated class D and that their technology is rated Class A. Also, he said that it takes 300 hours before the amps are broken in and start to sound the way they will stay. How man of you have listened to them after they were broken in by 300 hours? I just feel like so many people comment on things they heard for a few minutes or that the are just spouting off opinions they read or heard from a dealer and saying they are their own experiences. I just wish people researched things more before they comment to someone with questions. He does them an injustice.

Eliahu, my experience is somewhat between cursory and extensive. I spent about 4 hours with a dealer and the 201 were among three amps I listen to. I am not sure how much the devices were broken in, but I know they had been running for several days. I loved the 201 monos, but they could not drive the ManePan 3.6 speakers enough. If the recording got a little excited, the soundstage flattened down. I suspect the 501 pair would have done a lot better. It is worth investigating the 201 and 501 chipsets further. the Rowland web site suggests that 302 and 301 are in fact using the IC chipset, which is made by B&O.

I have a Rowland 2 chasis version of the model 8t.Although it is human nature for all of us to justify our own equipment,let me tell you a bit about my experience.I have owned,happily, CJ tube Equip as well as Audio research.I try to hear all current stuff so as to keep up to date.I switched to the Rowland because I wanted Stability(no tube problems)and was tired of the heat associated with tube amps.Originally my second chasis housed the battery power supply,which performed superbly.However,I noticed,on the Rowland website,that I could update my battery chasis to the new SWITCHMODE POWER SUPPLY technology.This was supposed to be even quieter than the pure d.c. battery,and give me a power rating that doubled my battery power(from 100 wpc to 200 wpc).I may as well state that I had zero complaints about the performance of the battery on my AVALON ASCENTS(a very easy load).What I was REALLY not prepared for was the incredible improvement,in virtually every area,that was brought about by the NEW power supply technology.I mean it was now even quieter on backgrounds than the already DEAD QUIET battery,which I still can't figure out.I can only imagine how fabulous the newer Rowland stuff must sound,and he has found a way to reduce size and offer real value in seemingly low prices,as compared to some of the other overpriced stuff.Let alone NO HEAT and GORGEOUS build and metalwork.More importantly,I really can't say I hear any real improvements in music reproduction with the better tubed stuff,as compared to my Rowlands.I still love the sound of QUALITY tubed equip.,but my Rowland sounds,to me,and without rationalization,as accurate at reproducing musical notes as anything I've heard,AND I don't have to sit in my bathing suit(in January,in N.J.)!!

I have just posted a brief update on the development of the upcoming Pass X600.5. Please see:
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1100367851&openmine&zzGuidocorona&4&5#Guidocorona