Yep, he's a lovely chap...and knowledgeable too - go figure!
One of videos "perhaps" worth going through:
Maybe. But its not the whole or exact truth either. Its more like the view of an EE who is not the 50% of the population who hear below some threshold of audibility. Where he is right is that most audiophiles don't understand physics and or physical causation. They also fool themselves sometimes. 'Different is automatically better,' is a common mistake. Despite those problems, it would also be a mistake for an EE to jump to a conclusion that it must all be imaginary.
well what threshold does he quote? And is that a threshold with music or sine tones. If the latter then your 50% is straight out the window.
Over 10 years ago Gary Pimm and I did some testing of a large power filter that someone had sent me to evaluate. It was meant for audio equipment, and was about 2 liters in volume inside a metal box. Typical LC and MOV filtering. Gary and I used spectrum analysis up to several MHz to see what, if anything, the device blocked or filtered.
One thing we quickly found is that mains power line noise makes for an inconsistent test signal. The AC mains noise was forever changing, making it difficult to compare two measurements, let alone multiple measurements. The other thing that quickly became clear was that power filters, especially the one under test, where very good at keeping the noise IN. The power conditioner blocked noise from exiting into the mains, but that meant that the noise in the DUT was now much higher than without the filter. It looked as though the AC mains functioned as a low impedance noise sink. When that path was blocked by the power conditioner/filter, the noise rose significantly inside the DUT.
This was just a casual basement lab test, though done with high end test equipment. Not a listening test at all, just spectrum analysis of AC mains noise. We didn't publish anything, but it did teach me a lesson that noise isn't easy to fix. You might buy a very nice, well designed power filter that will end up giving you more noise in your device than you started with. I do feel that this an area ripe for study.
Absolutely - anytime new evidence is presented we should be willing to acknowledge that our current beliefs, no matter how tightly held, may in fact be incorrect. Call it critical thinking. The key word there, though, is "evidence." Evidence is not someone just saying "I hear it!" no matter how highly they may think of themselves. As an EE who does their best to think critically (in spite of a very stubborn streak) this means demonstrable, repeatable evidence generated in the appropriate and legitimate manner.
Hal
Many common power conditioners rely on large inductors in series with the AC line, MOVs, etc. Those tend to be the ones that don't work well. The top of the line conditioner designed by Richard Marsh and Demian Martin is still one of the best ever. Schematics were once posted in one of the Blowtorch threads. Of course, they don't tell everything about the construction.
Power cords. In the US your power cord should always be rated to the breaker in the distribution box. So 15A in most cases, as I understand. The reason is, that is your last fuse protection point. It's the rated fault current on that supply. In the event your amp goes short circuit it's the current that cable will need to survive until the breaker pops.
The same can be said for a Live/Line fault to Earth if you don't have a CFCI / trip device.
That means, full heavy gauge "kettle" or kitchen appliance style cords.
In the UK, if you want to use lighter cable rated for 3A, then you need to replace the fuse in the plug to be 3A.
Not doing this will increase your fire risk exponentially.
The same can be said for a Live/Line fault to Earth if you don't have a CFCI / trip device.
That means, full heavy gauge "kettle" or kitchen appliance style cords.
In the UK, if you want to use lighter cable rated for 3A, then you need to replace the fuse in the plug to be 3A.
Not doing this will increase your fire risk exponentially.
Yes, when I have discussed this with power filter designers over the years, they have said much the same thing. It was nice to learn what works and what does not. I would certainly not feel up to designing a good one. 😉
But pity the poor consumer who knows little to nothing of power filter design, or what is inside the device he is buying. How to know, how to choose?
It also seems that in this thread there is sometimes confusion in posts between "AC line cords" and "AC power conditioners or filters" with people ascribing the qualities of one to the other. AC power conditioners and filters can, in the presence of certain types of noise riding on the incoming power, easily make an audible and measurable difference in the quality of the amplified signal.
Basic, AC power cords sized for the required load... Not so much.
Hal
Basic, AC power cords sized for the required load... Not so much.
Hal
There have always been and still are periods in the development of science and engineering when we have partial evidence something exists, but not a full theoretical understanding. For example, there is no principled mathematic theory to 'prove' or explain exactly how AI works. Yet most of us believe there is something still under development that is AI.
Historically, there were periods when soliton waves had been observed but a soliton solution to the wave equation was not known.
We are in a similar period with respect to a more detailed understanding of how humans hear. It is still an active area of scientific research.
Regarding music reproduction, some of the evidence is only available as of today by careful listening to certain reproduction systems. IOW, by human observation. Even then, recognition of everything that is perceptually audible may not ever come to every person. An example we all accept as true is prefect pitch. Some people have it, some don't, and it appears to be something that if learnable must be learned at very young age, mostly as an infant.
So, maybe wiser to withhold judgment on some things rather than jump to conclusions that will likely later be shown to be scientifically incorrect. However it seems that some people have a deep need for certainty. Jumping to conclusions, even wrong ones, can be a way to relieve the human psychic tension of uncertainty.
Last edited:
Yep. You can get lost for hours browsing the noise floor on the scope.
Thing is, that's only half the story too. You are still measuring mostly differential noise (relative to Earth Ground if you used an ER scope). Even more of that noise is common mode noise. So if there is a spike on both phase and neutral, the differential probe will not show it. There are other ways to measure common mode noise, check EEVBlog's videos on measuring DC power supply ripple and common mode noise (DC side yes)
If you loop a probe back on itself to create a little loop antenna you can browse the basic "field noise" in the environment. ALL of that will become common mode noise on all conductrs in the vicinity.... unless they are properly shielded and differential.
They have measurable distributed capacitance and inductance at RF frequencies, don't they? Some are shielded, some aren't. AC lines are known to act as antennas and or conductors of EMI/RFI. Anyone knowledgeable in electronics should realize that. Power cords are not just resistors. That is a simplification, and can be an example of jumping to conclusions.
Depends what you mean by 'AI'. There is no 'intelligence' just a rebranding of what used to be called expert systems and a very poor example to justify your beliefs.
Using true scientific endeavour to justify audiofool woo and foo just makes more people worry about your hidden agenda.
Now if you do want an example at least quote something human linked such as tetrachromic vision. For years this was not believed to exist and has been proven in a very small percentage of women (men lack the genes).
Using true scientific endeavour to justify audiofool woo and foo just makes more people worry about your hidden agenda.
Now if you do want an example at least quote something human linked such as tetrachromic vision. For years this was not believed to exist and has been proven in a very small percentage of women (men lack the genes).
They do know that. They also know that any effects are not enough to make any measurable difference. Yes, anything is theoretically possible and there is always the exception that proves the rule, but that is exactly what it is... an exception.
They can be enough to make an audible difference, so they must be physical and thus measurable in principle. Maybe doesn't show up well on a steady state FFT. That could be.
- Status
- Not open for further replies.