Blind Listening Tests & Amplifiers

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Re: Re: VIBERATIONSSSS

nw_avphile said:




I'm not sure you understand the test? Coloration was what SY was talking about in point #1 that he made on the previous page and I answered at the top of this page. It does show up. ANY amplifier colorations, intentional or otherwise, will show up in a null test.




Coloration of the amp due to topology or coloration due to parts used?

It is just me, but I did tests with a single series resistor at the amp's input and ea. resistor had it's own different sonic signature. If we change just one resistor in our amp under test and assume it could be detected sonically, will it show in a null test?

If the answer is yes, then we have a perfect tool to choose resistors for best sound. I wonder which resistor would test best?

If the answer is no, than we have two alternatives. Either we were mistaken and there is no difference in sound of resistors, or the test is simply no good.

So what is your answer, nw avphile?;)
 
diyAudio Senior Member
Joined 2002
Hey! We're getting closer...

Hi,

Hey! We're getting closer...

No...not really.
Where have you been for the past fifteen years?

You assume we haven't done that kind of testing..we did...hundreds if not thousands of music lovers did that ten to fifteen years ago already...

We arrived at our conclusions back then which explains the opposition you're facing here...been there done that kinda feeling, you see?

Mind you, I was surprised to see that after so much effort, so much product and engineering leaving the door in the eighties, nineties, when joining the forum late August last year I still meet with the same objections.

No personal offense to any of you but "Educating Rita" seems to be a lifetime commitment.

Cheers,;)
 
Peter, you remind me of that old riddle about two men standing in an ordinary room, call them Porgie and Mudhead. Porgie is taller than Mudhead. Mudhead is taller than Porgie.

What are the two possible solutions to this seeming conundrum?

1. I'm lying.

2. I'm mistaken.


I think you actually said something quite profound earlier in the thread. There IS a difference between perceiving a difference when you already know in advance that there is one, and perceiving a difference when you DON'T know that in advance. I'm quite certain (99.99%) that you perceived a difference in those output resistors. I'm also pretty certain (95%) that if you didn't know whether a pair of amps had different resistors in them, you would be unable to tell with better than chance probability whether the two amps sounded identical or not, assuming the resistors had the same value and similarly low C and L parasitic impedances.
 
SY said:



I think you actually said something quite profound earlier in the thread. There IS a difference between perceiving a difference when you already know in advance that there is one, and perceiving a difference when you DON'T know that in advance. I'm quite certain (99.99%) that you perceived a difference in those output resistors. I'm also pretty certain (95%) that if you didn't know whether a pair of amps had different resistors in them, you would be unable to tell with better than chance probability whether the two amps sounded identical or not, assuming the resistors had the same value and similarly low C and L parasitic impedances.

So it comes to the point we started with. One camp says there is no difference in the sound of parts and it is only psychological effect and that null test is the perfect tool for measuring amps for best sound.

The other camp says that ea. part has it's sonic signature and makes the sound of the amp in addition to a given topology. The null test doesn't show everything. I don't think we can move any further in our discussion then and the argument wil never be resolved.
 
Re: Re: Re: VIBERATIONSSSS

Peter Daniel said:
Coloration of the amp due to topology or coloration due to parts used?
Both... when I say "any coloration" I mean ANY. If anything in the amplifier makes the output different than the input, it shows up in the null difference signal.

Peter Daniel said:
It is just me, but I did tests with a single series resistor at the amp's input and ea. resistor had it's own different sonic signature. If we change just one resistor in our amp under test and assume it could be detected sonically, will it show in a null test?

If the answer is yes, then we have a perfect tool to choose resistors for best sound. I wonder which one would test best?

If the answer is no, than we have two alternatives. Either we were mistaken and there is no difference in sound of resistors, or the test is simply no good.

So what is your answer, nw avphile?;)
There are two parts to the answer. The first might be if you say used an inductive resistor in a sensitive spot in the amplifier (the front end or feedback loop for example) it may well cause a change in the null test result.

The second part is there's a THIRD choice to explain hearing something that doesn't show up in a null test. It's called psychological bias and it's the basis for this entire thread.

It goes something like this: You have read, heard, been told, or otherwise suspect that resistors make a difference in the sound so you order up some different brands to find out. Some of them are kind of expensive ($28 in your case?).

The resistors arrive and you take your amp out of your system, take it apart, solder in the first brand of resistors, put it back together, and connect it back up in your system. Some might also let it warm up and/or burn the component in. All told, it will take some time and effort.

You sit down for a critical listen with your favorite music. At this point you've invested considerable time and money into this whole resistor thing, and what's more you're expecting resistors indeed make a difference, so guess what, you HEAR a difference even when there might not BE one!

Remember as a kid when the baseball coach, or teacher, or your mom told you that if you think you're going to fail you probably will? That works the same way with audio. If you THINK there are supposed to be differences, you'll probably hear them regardless if they're really there.

This can easily be proven by pulling the sorts of dirty tricks on people I outlined earlier in this thread. If I put a cheap receiver in your system and you believe it's playing when you come into the room, you're likely to say it sounds really AWFUL. I then turn the receiver off and the music keeps playing because it's really your system and nothing has changed. You were biased by the knowledge you thought the receiver was playing so it genuinely sounds bad to you.

It works just as well in reverse. I hook the receiver up but lead someone to believe it's their own system, and they'll not notice anything's wrong despite the fact they're listening to something they'd normally hate.

How do we resolve this psychological bias? BLIND TESTING!

I won't keep repeating myself. If you want to know more, read back through this thread and check out some of the references listed. This stuff is well documented but not widely published among audiophiles for obvious reasons.
 
Peter Daniel said:
So it comes to the point we started with. One camp says there is no difference in the sound of parts and it is only psychological effect and that null test is the perfect tool for measuring amps for best sound.
Well that's not my belief. I believe there are differences, in some cases, between the sound of parts. But only when you can actually hear them in a BLIND test (or measure obvious distortion by some means).

There are a lot of things, that to my knowledge, haven't been put to a rigorous test. Vibration is one of them. It might be there are some measurable (and hence possibly audible) differences.

I also believe putting an electrolytic cap (especially a cheap one) in the wrong place in a circuit may well cause audible problems. Doug Self has already shown it causes measurable problems. So replacing an electrolytic in a critical location with a quality film cap may well improve the sound.

So I'm not saying a lot of things can't make a difference, I'm only saying you shouldn't let yourself be biased by knowing what you're listening to when you're evaluating amplifiers.
 
Flying in circles...

I won't keep repeating myself. If you want to know more, read back through this thread and check out some of the references listed.

Hi Nw_phile...sure i realy appreciate your eforts here...but i think that some people here don't want think a bit about the test...
If the output is the same of the input...what we need to proof???
If that don't make sense for some people...what can we do??

If you tell the people that a new resistor with a price tag of 50 USD play wonders in your sistem...everybody will believe in you and nobody will say that you need to prove it!

Strange world!!!
 
Re: Re: Re: Re: VIBERATIONSSSS

nw_avphile said:

Both... when I say "any coloration" I mean ANY. If anything in the amplifier makes the output different than the input, it shows up in the null difference signal.


There are two parts to the answer. The first might be if you say used an inductive resistor in a sensitive spot in the amplifier (the front end or feedback loop for example) it may well cause a change in the null test result.

The second part is there's a THIRD choice to explain hearing something that doesn't show up in a null test. It's called psychological bias and it's the basis for this entire thread.

It goes something like this: You have read, heard, been told, or otherwise suspect that resistors make a difference in the sound so you order up some different brands to find out. Some of them are kind of expensive ($28 in your case?).

The resistors arrive and you take your amp out of your system, take it apart, solder in the first brand of resistors, put it back together, and connect it back up in your system. Some might also let it warm up and/or burn the component in. All told, it will take some time and effort.

You sit down for a critical listen with your favorite music. At this point you've invested considerable time and money into this whole resistor thing, and what's more you're expecting resistors indeed make a difference, so guess what, you HEAR a difference even when there might not BE one!

Remember as a kid when the baseball coach, or teacher, or your mom told you that if you think you're going to fail you probably will? That works the same way with audio. If you THINK there are supposed to be differences, you'll probably hear them regardless if they're really there.

This can easily be proven by pulling the sorts of dirty tricks on people I outlined earlier in this thread. If I put a cheap receiver in your system and you believe it's playing when you come into the room, you're likely to say it sounds really AWFUL. I then turn the receiver off and the music keeps playing because it's really your system and nothing has changed. You were biased by the knowledge you thought the receiver was playing so it genuinely sounds bad to you.

It works just as well in reverse. I hook the receiver up but lead someone to believe it's their own system, and they'll not notice anything's wrong despite the fact they're listening to something they'd normally hate.

How do we resolve this psychological bias? BLIND TESTING!

I won't keep repeating myself. If you want to know more, read back through this thread and check out some of the references listed. This stuff is well documented but not widely published among audiophiles for obvious reasons.

You don't know me, then. I like to be practical and this is a simple setup for resistors sound comparison. It takes only few seconds to change resistor so you still have the memory of the sound of the previous one. Of course some will argue that this is not valid setup, because I don't solder resistors and it's outside of the amp so all kind of interferences come in effect. Yet it allowed me to hear repeted and consistant difference with few types of resistors and it was perfectly in line with other forum members. If you will continue to claim that resistors don't have specific sonic signature I simply refuse taking seriously anything you say.;)

And BTW, I never use inductive resistors.
 

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Re: Re: Re: Re: Re: VIBERATIONSSSS

Peter Daniel said:
You don't know me, then. I like to be practical and this is a simple setup for resistors sound comparison. It takes only few seconds to change resistor so you still have the memory of the sound of the previous one. Of course some will argue that this is not valid setup, because I don't solder resistors and it's outside of the amp so all kind of interferences come in effect. Yet it allowed me to hear repeted and consistant difference with few types of resistors and it was perfectly in line with other forum members. If you will continue to claim that resistors don't have specific sonic signature I simply refuse taking seriously anything you say.;)
You're certainly welcome to refuse to stop taking me seriously. I'd already assumed you were too far on the subjective side of things to take me seriously. I'm spending all this time typing mostly for the benefit of others who are reading this thread.

Your resistor swapping set up would be fine if you had two identical amps, one with your "reference resistors" and one with the DUTs (Devices Under Test--new resistors in this case). You could then compare the two amps in a blind test and decide if the different resistors were making any difference.

But you, yourself, suggested a potentially much easier way to evaluate resistors earlier. That's the null test.

If you can't tell any difference in the null results between two brands of resistors, it's a VERY safe bet you also couldn't HEAR any difference between them in a blind test. If you don't agree with this statement, you need to explain how the audible differences are somehow escaping the null test?
 
SY said:


That's a bizarre reading, if I do say so. Where did I ever say such a thing?

I thought you meant it here:

SY said:
I'm quite certain (99.99%) that you perceived a difference in those output resistors. I'm also pretty certain (95%) that if you didn't know whether a pair of amps had different resistors in them, you would be unable to tell with better than chance probability whether the two amps sounded identical or not, assuming the resistors had the same value and similarly low C and L parasitic impedances.
 
Re: Re: Re: Re: Re: Re: VIBERATIONSSSS

nw_avphile said:

You're certainly welcome to refuse to stop taking me seriously. I'd already assumed you were too far on the subjective side of things to take me seriously. I'm spending all this time typing mostly for the benefit of others who are reading this thread.

Your resistor swapping set up would be fine if you had two identical amps, one with your "reference resistors" and one with the DUTs (Devices Under Test--new resistors in this case). You could then compare the two amps in a blind test and decide if the different resistors were making any difference.

But you, yourself, suggested a potentially much easier way to evaluate resistors earlier. That's the null test.

If you can't tell any difference in the null results between two brands of resistors, it's a VERY safe bet you also couldn't HEAR any difference between them in a blind test. If you don't agree with this statement, you need to explain how the audible differences are somehow escaping the null test?


One possible answer could be that measurements are done in two dimentional environment and we perceive music in three dimentional environment so it doesn't correlate well (if I can say so;))

It is actually better to do resistors test in one amp, because you can never position two amps in the same space in exactly same way. Both may be affected by different resonant modes and this cause the test to be invalid. Having two different amps involves two different sets of wiring and this is an additional variable.

Seeing no difference in null test between two different, same value resistors might also indicate that null test has a potential flaw.
 
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