Yes, I would suggest two equivalent bargain basement, "good enough" power amps which are tested to give high null difference at the outputs between the pair, when fed from the same, reasonable quality mains. Then, use one spur of mains totally cleaned up, as free from nasties as possible, for one unit ... and the other connect to a very dirty mains spur, with the addition of a signal injector which adds as nasty a mix of typical mains noise as we like. And run again for differences at the outputs ...
Of course, in our comfortable little, 'objective' world, nothing whatsoever will alter ...
Of course, in our comfortable little, 'objective' world, nothing whatsoever will alter ...
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Yes, I would suggest two equivalent bargain basement, "good enough" power amps which are tested to give high null difference at the outputs between the pair, when fed from the same, reasonable quality mains. Then, use one spur of mains totally cleaned up, as free from nasties as possible, for one unit ... and the other connect to a very dirty mains spur, with the addition of a signal injector which adds as nasty a mix of typical mains noise as we like. And run again for differences at the outputs ...
Of course, in our comfortable little, 'objective' world, nothing whatsoever will alter ...
Complete miss.
The discussion has moved on to suppositions of pre-existing noise on the power line. You can inject as much noise as you like if you are deliberate, but the implied claim in a.wayne's post is/was that power lines are obnoxiously dirty to the point that it affects audio quality. So, what evidence exists to substantiate this position?
Or I am misrepresenting him. Feel free to correct me.
The pre-existing noise can come from a number of sources, deliberate injection is just a way of managing repeatability, something someone mentioned at one time, . It's been mentioned a number of times that the worst offender is usually appliances, etc, within the residence itself or nearby; so we should go around and pull everything from the wall sockets when we do serious listening; and if we live in a set of units, bang on the neighbours' doors and tell them to shut everything down, it's "nice" music time ...
IOW, the lines are noisy, as a random, uncontrollable situation - the only intelligent solution is to make your situation robust against that ...
. It's been mentioned a number of times that the worst offender is usually appliances, etc, within the residence itself or nearby; so we should go around and pull everything from the wall sockets when we do serious listening; and if we live in a set of units, bang on the neighbours' doors and tell them to shut everything down, it's "nice" music time ...IOW, the lines are noisy, as a random, uncontrollable situation - the only intelligent solution is to make your situation robust against that ...
Already mentioned many times by marce, this, Designing for Interference-free Audio System Components, discusses what could or should be done, from one angle, if one wants to get serious about these issues ...
The pre-existing noise can come from a number of sources, deliberate injection is just a way of managing repeatability, something someone mentioned at one time,
IOW, the lines are noisy, as a random, uncontrollable situation - the only intelligent solution is to make your situation robust against that ...
Sorry, but no.
Is there ANY evidence that under typical circumstances and using competent equipment, line noise contributes an audible interference in an audio playback circuit?
Well, that's as close to a "How long is a piece of string?" question as I've seen in some time - define, rigorously, "typical circumstances", and "competent equipment" ...
I worked for 8 years for a company that does genset controllers including mains sync controllers, we had measurements of the worlds mains supplies. If you live in a residential area (UK especially) your mains should be pretty decent and even if you live near a industrial estate with todays regulations it shouldn't be that bad. Different countries can have different problems, UK USA etc have distributed mains with huge inertia behind the supply, others that don't have that have local generating plants and much less inertia, so prone to upset if near a heavy user.
The main point (!) is that any equipment that's going to be hooked up to the mains should have a PSU and filtering that copes with the noise.
Cables (competent designed for the job) unless have some filtering components are not going to have any effect, from the socket to the unit.
The main point (!) is that any equipment that's going to be hooked up to the mains should have a PSU and filtering that copes with the noise.
Cables (competent designed for the job) unless have some filtering components are not going to have any effect, from the socket to the unit.
not so. All I'm asking for is one piece of evidence. Feel free to define all the rest for yourself as long as you let us know what your definition is.
As others have pointed out, its of huge interest to me that critical systems and equipment in medicine, engineering and science "make do" with pretty unremarkable power cords and a total lack of specialised filtering.
Why would they risk such inaccuracy?
Normal power cords, generally more/better filtering than commercial gear, mainly because the EMC requirements are more stringent, and a lot of the filtering is to also stop noise getting out.
But there is nothing magical or mystical about it as FAS42 seems to imply, basic engineering and EMC filtering, but it seems rather than invest in a few X1/X2 caps and possibly some PI/T filtering costing a few bucks, its better to spend thousands on a magic cable (that probably just has a few bucks worth of the aforementioned bits).
Well tell it to Bruno ....
"Many of these compatibility issues -- where people say this preamp sounds good with that CD player -- some of these mysterious interactions actually happen through the power wiring, and sometimes even through direct coupling from a power cable into a speaker cable. This, then, does to an extent explain why people put such an inordinate effort into speaker cables, and cables in general. All I can say is that once you realize you are looking at these crosstalk issues as one of the reasons for a sonic difference, you might want to do some more targeted experimenting,"
-Bruno Putzeys
"Many of these compatibility issues -- where people say this preamp sounds good with that CD player -- some of these mysterious interactions actually happen through the power wiring, and sometimes even through direct coupling from a power cable into a speaker cable. This, then, does to an extent explain why people put such an inordinate effort into speaker cables, and cables in general. All I can say is that once you realize you are looking at these crosstalk issues as one of the reasons for a sonic difference, you might want to do some more targeted experimenting,"
-Bruno Putzeys
Trouble is, are we talking about line noise, or power cords? Line noise is easy to "prove" - every time I ventured into that area I used the simple noise generator of manually manipulating a poor mains connections, making it spark, in the same spur as the audio - lots of carrying on came through the speakers from that. Nice and extreme, but demonstrates the linkage - this was my way of testing my own filter design, which stopped all audible crackling occurring.
Power cords would have some noticeable effect, if there was a level of mild filtering due to the construction - mains noise doesn't have to sound like "noise", the degradation can be quite subtle, and still be picked up by the ear.
Power cords would have some noticeable effect, if there was a level of mild filtering due to the construction - mains noise doesn't have to sound like "noise", the degradation can be quite subtle, and still be picked up by the ear.
Well tell it to Bruno ....
"Many of these compatibility issues -- where people say this preamp sounds good with that CD player -- some of these mysterious interactions actually happen through the power wiring, and sometimes even through direct coupling from a power cable into a speaker cable. This, then, does to an extent explain why people put such an inordinate effort into speaker cables, and cables in general. All I can say is that once you realize you are looking at these crosstalk issues as one of the reasons for a sonic difference, you might want to do some more targeted experimenting,"
-Bruno Putzeys
Coupling is not mysterious, have a look at JNs gallery for some pretty pictures on loops and coupling and again Henry Otts book covers this...You don't need magic cables just a bit of understanding what is going on and the coupling mechanisms involved.
Again is there any measurements, schematics of system set-ups to provide data for the above quote or is it all down to perception.
Cables DONT Filter...Filters filter. Though twisting your mains cables can have a beneficial effect...twisted pair.
As to making mains spark to test things, seriously not the best idea I have heard! If I was so concerned I would measure the mains to get a reference of noise present (a data logger would be best, you want to have at least 24 hrs of data) then decided what if any extra filtering was required. On home made stuff you also have to worry about your own gear putting noise out as EMC engineering is often overlooked in DIY designs.
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