I tell you what expensive is !

that Pass Labs Pre and that PS Audio P10

Just as well they do the job soooooooooooooo well

I'm wondering if actually it is possible to shed expectation bias completely, even if you are only interested in your personal findings and noone elses.

I would suggest that all of us have some kind of expectation bias operating at a sub-conscious level even if we haven't acknowleged it. A lot of us can invest a lot of time and energy pouring over reviews and forums to help us select their next 'upgrade'.  There can often be quite a lot of emotion invested in these decisions (consciously or subconsciously) which must surely influence our evaluation of new items in a positive or negative way.  I can certainly say that this could have applied to myself in years gone by.  I'm hoping I take a more disspassionate and neutral view now but I won't claim to be entirely free of any expectation bias based on brands / looks / reviews etc  I used to make up my mind about new bits of gear *extremely* quickly, possibly as a result of expectations, but have learnt not to do that any more.  A case in point would be the Sony ES amp I bought a year or so ago - on initial testing I was wowed by it but keeping it in the system for some weeks I found some traits that I could not live with long term. 

Craig (and others), my advice if you want to try a specialist fuse is to buy one 13A AMR Gold and use it in your main system feed or regenerator cable, if you have one, or the highest current device, probably your power amp.  If you don't hear a difference, then fair enough and you've only spent £20.  If you do hear an improvement, case proved and you can then go on to try more AMRs or an SR Red.

Absolutely.  I'm skeptical, but not beyond trying something out.  Some have expressed skepticism regarding mains cables - and I know not only that they make a perceptible difference by listening, but I also know how they do it.  I carried out a series of conducted susceptibilty tests for differences between mains cables, UKAS accredited at 3C Test www.3ctest.co.uk/ .  And the better mains cables provide around 25dB reduction in conducted RF, both common and differential mode, as compared with a kettle lead, in the frequency range 10kHz to 2.5GHz.  3C test themselves were darned skeptical to the point that I had to persuade them to do the measurements - they actually only agreed because I have spent a shed load of money with them in the past.

Incidentally, this  is what 2,000,000V looks like  .  This is actually proof positive that absolutely the best place to be in a thunderstorm is in your car (=Faraday Cage), but I absolutely guarantee that a Red, or any other, 13A fuse would have blown ;-)

Craig 

A few turns of cable on a ferrite toroid will reduce RF fantastically and is the standard cure for RF based EMI. This will work with any old kettle lead and does not need money spending on the problem.... I very much doubt the 25dB from 10KHz to 2.5GHz reported by Craig.. too big a reduction over too wide a bandwidth.

Guys, the information presented here is too important to cloud it with insults. Please desist but by all means continue the debate.

OK.
Again, please would you try to prevent this becoming more heated? There is some over-reaction as well as some ill-advised choice of words going on and we don't want this to spiral into anything worse.

Check.  Agreed with entirely Chris.

Craig

What is the proper test?  How have those tests demonstrated that a mains cable affects the sound.  I repeat the comment made (originally with reference to your mains regenerator plots, way back at the start).  If you want to measure the effect of mains on the sound, measure it on the output of the amplifier - not the input to its power supply.   I believe you can measure noise down to -130db (but my reference I would have preferred to check with is on holiday in Teneriffe atm, so I could have that wrong)

Again - I can measure the voltage on my houses domestic mains, and show it changes, from day to day.  That doesn't show it affects the sound from my HiFi.  I can change the DC voltage supplied to the Pip (within limits) and it won't change the amplifiers sound.  I discussed adding the dual mono power supply to the Quad 405-2 mods carried out for me recently, and got the comment back "if you are going to do it, then it needs to be true dual - not 2 windings round a common core, BUT THE CURRENT DRAWN BY THE AMPLIFIER COMES FROM THE RESERVOIR CAPACITORS.  THE TRANSFORMER IS ONLY TOPPING THEM UP.  So it will have no affect."

Just because I can measure something, doesn't mean it has a causal link with sound quality.  I can measure the length of the carpet.

I refer you again to my (recently revised) signature.  And there is another issue, which I will repeat in this post.  Never mind scientific measurements, still NOBODY in my experience has ever provided a convincing demonstration that a difference in ANY mains cable or fuse can be heard.  When I tried an "audiophile" mains cable i could hear no difference - and as predicted before the test, was told I had inadequate hearing, the wrong sort of mains, or an insufficiently audiophile cable.  (I should note 2 respected HiFi designers are keen for me to do listening tests for them after January).  At a show - running a dem room, where he could almost certainly borrow one buck-shee, if Arthur thought an exotic mains lead would change the sound of his dem system, he would fit it.  None of my experience in HiFi has ever produced a credible, non Emperor's new clothes, demonstration that a mains cable changes the sound.  Together with the science, that is suggestive that it doesn't change the sound.  There is a strong odour of decaying marine life about this paradox.