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In Reply to: RE: Not usually... posted by FenderLover on September 13, 2016 at 13:29:53
"The brain plays such a strong influence on how we process"... what we think we hear.
If a person is trying to really understand (and build) a music playback system that IS really properly reproducing the input signal...I would say they need to know what is and what is not "placebo effect".
That isn't going to happen if we just repeat "But, even if it is a "placebo effect"... as long as the patient (or listener, in this case) feels the positive effect --- all should be okay? "
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Follow Ups:
Problem is... it can be hard to separate the two.
8^)
Yes! It's very hard not to get fooled.Even professional listeners have a hard time not being fooled.
This is why it's so important that good scientific method has to be followed before proclaiming that X is "better" than Z.
Otherwise the claimant could just be "fooling" himself (and by extension, trying to fool you and me) when there is, in fact, no actual basis for the claim to start with.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/13/16
Reproducibility is the word!
8^)
That's for sure.
Case in point, if there was a clear reason why changing the leads on the cap would make a big difference then OK, but the fact is a screen grid bypass cap merely holds the screed grid at AC ground.
There is no way mathematically that the tiny difference in the resistance, inductance, capacitance, dielectric absorption, etc.. between the stock lead wires and the new added lead wires would hold the screen grid enough closer to ground to make the claimed difference. "dynamics just soared with the modified caps"
In this case one would have to do a DBT. If a claimant and/or other listeners could show statistically significant results in a DBT then we would need to look for a different reason for the change.
In the mean time, expectation bias is more likely the cause of what is being "heard".
If someone secretly undid the change I don't believe the listener would notice that the system had lost the perceived added dynamics.
The listener would assume that the modified leads were still in place and the expectation would remain, so the perceived improvement would remain.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
You've touched on a major question that is always worthy of consideration. One wonders if perhaps the OP replaced a 2.8uF capacitor, the value called for in the schematic, with the 4.7uF Clarity MR cap that he had modified, in which case, the improvement he heard could have been due more to increasing the value of the capacitor than to adding wire to the leads. I am sure he can answer that question.
I am a doctor, too, albeit a non-practicing one. Today I visited a dental surgeon who placed an implant in my lower jaw. During the procedure, he numbed me up very effectively, but of course the local anesthesia started to wear off by mid-afternoon, and I really began to suffer. Thereupon, I took a codeine tablet, which did nothing for me until at least 45 minutes had passed. Why don't doctors experience the placebo effect?
One huge placebo effect for audiophiles is brought to bear after one spends a great deal of money on a component or some other less obviously functional element of a system. There is a strong subconscious bias to favor that which is new or expensive. Just check out Tweaker's Asylum some time, for proof of that.
"See the attached schematic which calls for a 2.8uF cap, but it currently has the 4.7uF cap with the modified leads."
I kind of missed that. That is to say, it didn't dawn on me that banpuka might have meant that he replaced a 2.8uf cap with a modified 4.7uf cap.
That might explain a lot.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Driven by an AC supply, a capacitor will only accumulate a limited amount of charge before the potential difference changes sign and the charge dissipates. The higher the frequency, the less charge will accumulate and the smaller the opposition to the current, therefore; higher frequencies MAY improve with a larger value capacitor in that position.
The Mind has No Firewall~ U.S. Army War College.
Yes, the reactance of a larger cap is lower than the reactance of a smaller cap.In this application that would make a better connection to ground at all frequencies (not just the higher frequencies) for the screen grid.
If it is the case that the OP replaced a 2.8uf cap with a 4.7uf cap and then reported that he heard a difference, then that would be completely understandable.
On the other hand if the original poster had already changed (at a previous time) the 2.8uf for a 4.7uf (or built the amp with a 4.7uf to start with) and is not reporting on that change in sound but is reporting on a change in sound having do to with the modified leads on the 4.7uf, he might be fooling himself (through expectation bias or whatever) and some proof of a real change in the sound will need to be proven through a DBT or a better explanation of the science involved.
Update; in the post linked below the OP has confirmed that he is indeed reporting that the perceived change in sound was between a 4.7uf without the leads modified and the same 4.7uf cap with the leads modified.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/14/16
!
The Mind has No Firewall~ U.S. Army War College.
You may not have felt relief for 45 min because you understand the kinetics. Which may or may not be a good thing, in the short term. But, best in the long run... Maybe.
Edits: 09/13/16
To bring this back to audio, if the goal is to advance the audio reproduction state of the art.....it's always a good thing to not be influenced by anything but actual physical reality.
I think we are all in agreement that that is hard to do because we are all so easily fooled when it comes to what we see and hear. It's built into our brains to work that way.
All the more reason to be cautious.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
...We certainly are. Even Richard Feynman realized this and made a big deal of it. This is partly why great claims must be independently reproducible by parties not directly involved with the "discovery". Not a frequent occurance in tweak audio.
Yah...Feynman was indeed on to something...:)
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
This is why reproducing results under controlled conditions is so important. Ideally, with error factors included.Subjective views are hard to quantify, but they play a role in audio. Just look at all the adjectives used to describe what you hear. Most are subjective, not objective or quantifiable. I'd say this is impossible to completely eliminate.
Edits: 09/13/16
...that may be so for now but we shouldn't stop trying.
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