[bhobba]

Hi Andy

Also with respect no one questions that loudspeakers sound different.  And yes mood can affect judgment of them as well so blind listening is also of value.  However people like Peter Aczel and Tom Nousaine believe all amplifiers with low distortion, not driven to clipping, and not driving difficult loads sound the same and can produce double blind studies to back it up.
http://bruce.coppola.name/audio/Amp_Sound.pdf
That being the case those who do not subject their views of amplifyers to blind tests and are unable to explain why the other tests failed to detect a difference will always be on the back foot.  
http://www.stereophile.com/features/113/
All that is required to dispel any concerns is simply have a someone switch the amp in and out and see if you can reliably pick which is which. Even more people believe cables sound the same so dispelling that by means of blind testing is obviously even more important.  To me that is just common sense - not arrogance.

Thanks
Bill

[andyr]

Hi Andy

... However people like Peter Aczel and Tom Nousaine believe all amplifiers with low distortion, not driven to clipping, and not driving difficult loads sound the same and can produce double blind studies to back it up.

...Bill...

Hi Bill,

To me that statement is comparable to saying "all amplifiers with low distortion driving "easy speakers" and playing very softly will sound the same".

I'm sure they do!  However, in the real world:

a) You don't listen at miniscule sound levels!  I want to listen at what I call "normal" listening levels from 4m away from the speakers (in an 8m long room).  Not head banging levels but comparable to what I would hear in at a symphony concert.

b) not all speakers are easy loads.  My Maggies in particular sing when they are driven by high-current amps.

Under these conditions, you don't need blind tests to decide which amp is better ... even though I would qualify that statement by agreeing with rabbitz who said that long term listening was preferable.  By definition, long term listening (in case you hadn't grasped the concept ... is so you can take your time to decide which is the best amp) implies non-blind tests!

And, as you said, your mood while listening is important ... hence only long term listening will allow you to listen to something through all your different moods.

Regards,

Andy

[bhobba]

Hi Again Andy

To me that statement is comparable to saying "all amplifiers with low distortion driving "easy speakers" and playing very softly will sound the same". I'm sure they do!

Yes indeed under such conditions I suspect differences will be hard to pick.  But I also suspect experienced listeners feeding speakers they know well can do it - although it would not be easy.  John Atkinson for example claims he can not it reliably.

Under these conditions, you don't need blind tests to decide which amp is better ... even though I would qualify that statement by agreeing with rabbitz who said that long term listening was preferable. By definition, long term listening (in case you hadn't grasped the concept ... is so you can take your time to decide which is the best amp) implies non-blind tests!

I have to say when I tested the Pioneer and Rotel on my Axis LS88's the difference was immediately obvious - the music was very thin from the Pioneer even though we matched SPL.  The Rotel had much more body.  Although it was obvious I still did a blind test anyway to be sure.

And, as you said, your mood while listening is important ... hence only long term listening will allow you to listen to something through all your different moods.

I think long term listening is very important for a number of reasons - what you say above, ensuring the sound is not fatiguing and the more familiar you are with a system the more readily you can pick subtle differences.  Experienced reviewers like John Atkinson claim that equipment that blind listening tests show sound the same do sound different when you use then for extended periods.  Problem is those of the objectivist school may claim you are being influenced by pride in using what perhaps is a higher status product.  So it is wise in such a cases to check you can reliably pick it in a blind test.

Andy, I have really enjoyed our discussions.

Thanks
Bill

[Geoff-AU]

Yeah..  long term listening does reveal a lot more than a quick A/B.  I think listening to two preamps/amps/cables/whatever for an extended time and THEN doing a blind test is still valid, because it leaves the judgement purely up to your ears - you can't see a bling amp sitting in front of you to bias your opinion

At the very least, such a blind test would prove whether there is a difference or not.  Personal preference will of course come into play but at the end of the day that's the user's choice.  If after listening to a pair of items for an extended period and knowing which one you're listening to you STILL can't pick it out then there's no difference between them.