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In Reply to: RE: Scientific evidence of power cables reducing signal distortion posted by reddogpt on June 18, 2009 at 12:01:02
One point that will surely be objected to as it fly’s in opposition to popular folk lore is that high end audio gear is usually well designed.
There are examples of good engineering but low cost and high looks are obviously very important and some problems show incomplete design. Not surprising in this day of fewer and fewer analogue and low RF designers I suppose.
In another area, that of test equipment or any industrial electronics really, the job of the power supply is to deliver a steady DC voltage, filtering out the hum and remnant AC, steady enough so that the operation of the circuitry doesn’t change with varying input line voltages.
Test equipment may be used right next to a transmitter or comparatively huge noise source as part of it’s job, it CAN’T be effected by that stuff or it will give erroneous reading.
Want to see some examples, examine any analyzer or Voltmeter from Hewlett Packard from the 1980’s to see excellent design.
I designed and built sections of experimental hardware flown on STS-7 and STS-51a, part of the acceptance testing was confirming it would all work normally with a horrendous DC supply and that the 100 Amp furnace controller didn’t radiate more than a small amount in air or by conduction.
The point I guess is that if in the home environment, a piece of electronics is effected by RF noise on its AC cord which is changed by a “better cord” than one is certainly by the very concept of proper engineering, dealing with a poor or incomplete power supply design, regardless of what it looks like or costs.
What if your power cords are designed to increase the magnetic field enough to change the phase of the current through them? What if that phase change is enough to seriously alter the charge cycle of the supply?
Is that also a design fault of the power supply?
d.b.
I see that sort of testimonial as a typical example of why it shouldn't matter , or if it matters it's poor design , often, as in this case, with analogies from other fields of electronics.Yet acknowledging that even though much "... high end audio gear is usually well designed" things like power line conditioning and power cords *do* often still make a difference.
It's just some can't wrap their brains around the fact, and despite all the noise, it is indeed fact.
Everything matters, don't forget to tweak your placebos!
Edits: 06/24/09
Um... If I may butt in and dispense with the double negatives I would paraphrase what Tom said thusly: 'If high-end audio equipment was really well designed, cables and environment wouldn't matter'. Since they do, it isn't. You guys are barking right up my tree so I'd like to hop up on my soap box and throw in my two cents worth.
While I largely agree with him, cables themselves are actually the source of some problems, especially triboelectric noise. Anybody that's stepped on a cheap microphone cable has heard that one...
It isn't just the competence, or lack thereof of the designers. Home audio is one of those pathological cases which superficially seems trivial, and yet isn't. While almost anything thrown together by almost anyone will work, designing a product that really works well, i.e. to the point that it is effectively transparent to the ear, is another matter. Here are a few reasons that come to mind..
1. The lack of systems engineering.
-The home audio system topology wasn't designed, it just happened.
2. The lack of meaningful standards.
-To put it bluntly, it's not important enough to governments or industry.
3. Unusually wide bandwidth.
- Three to four decades of signal bandwidth is huge.
4. In-band power.
- Having the 60Hz power supply and it's main harmonics where we hear is bad.
5. Extreme user sensitivity.
- Reducing distortion to where you really CAN'T be aware of it is tough.
6. Conflicting design approaches.
- Nowadays this is less of a problem due to switchers and mixed-signal designs, but traditionally audio guys were clueless about RF and the major rules of thumb are in conflict. It's hard to both star ground and maintain a Faraday shield.
Enough of that. It isn't trivial, there is no agreement on how good is good enough, what factors are important and how they are to be measured and weighted, or what the worst-case environment is that must be accommodated. The latter includes vibration, equipment interface, power supply, EMC and operators both deliberate and inadvertent. I'm trying to think if I know of anybody whose toddler HASN'T put a PB&J sandwich into the VCR.
But... I'm with Tom. The obvious goal is to design gear where all of these variables become, as much as possible, 'don't-cares'.
Rick
"It isn't just the competence, or lack thereof of the designers. Home audio is one of those pathological cases which superficially seems trivial, and yet isn't. "I don't think it's just home audio..... It's **all** audio....... If you think the stuff designed for the studio is of more competence, I'd kindly but strongly disagree. (I personally think Pro Tools is the single biggest monstrosity of a design ever conceived.) Just look at the horrible recordings that have been put out in recent time.
"While almost anything thrown together by almost anyone will work, designing a product that really works well, i.e. to the point that it is effectively transparent to the ear, is another matter. Here are a few reasons that come to mind..
1. The lack of systems engineering.
-The home audio system topology wasn't designed, it just happened."Systems engineering would force a home audio system to be of a "all in one" type design..... Unless every designer agrees upon what the system ought to be, this "lack" will go on indefinitely......
I personally don't think this facet of engineering is any more of a problem than other facets of engineering.
"2. The lack of meaningful standards.
-To put it bluntly, it's not important enough to governments or industry."It shouldn't be important to government, unless public safety is an issue...... (This is why we have UL standards, by the way.)
I do agree in regard to industry...... But it would require an across-the-board agreement amongst many backgrounds, so even if such objective is sought, the chances for successful implementation would be very slim.
"3. Unusually wide bandwidth.
- Three to four decades of signal bandwidth is huge."Not since digital audio has hit the scene. Bandwidth is limited to 22.05 kHz. And because of that, bandwidth in line and power amplification is no longer so important. So I strongly disagree here.
I also disagree in regard to bandwidth being a problem, unless it's so wide, it becomes susceptible to RF interference.
"4. In-band power.
- Having the 60Hz power supply and it's main harmonics where we hear is bad."The only solution to this is battery power..... Jeff Rowland, a so-called "home audio" manufacturer, has undertaken such approach.
"5. Extreme user sensitivity.
- Reducing distortion to where you really CAN'T be aware of it is tough."The user sensitivity has always been "extreme." The problem is too many in the design community are trying to convince the masses that associated discomforts should be tolerated to a degree or that the sensitivity is overrated. This is a big reason why audio design has been disappointing, in my humble opinion.
"6. Conflicting design approaches.
- Nowadays this is less of a problem due to switchers and mixed-signal designs, but traditionally audio guys were clueless about RF and the major rules of thumb are in conflict. It's hard to both star ground and maintain a Faraday shield."It's not difficult to make a star ground and Faraday shield...... It's that the latter has been deemed unimportant. Whether it is or not is subject to debate, but I will say the internal RFI generated from digital devices has rendered the Faraday shield ineffective. Although it should still be used on purely analog components like phono stages.
In regard to "clueless about RF", this is a problem for most designers across the board, not just home audio. The RFI generated by digital devices has changed everything.
Conflicting designs in itself is not an issue. The might both be competent, they might both be incompetent, and anything in between.
"Enough of that. It isn't trivial, there is no agreement on how good is good enough,"
Now here you hit on an issue. When in doubt, raise the bar, not go the easy route and think a lesser design might still fly. This IMO is a big problem in modern audio design. The bar simply hasn't been set high.
"what factors are important and how they are to be measured and weighted, or what the worst-case environment is that must be accommodated. The latter includes vibration, equipment interface, power supply, EMC and operators both deliberate and inadvertent. I'm trying to think if I know of anybody whose toddler HASN'T put a PB&J sandwich into the VCR."
Or oatmeal.
"But... I'm with Tom. The obvious goal is to design gear where all of these variables become, as much as possible, 'don't-cares'."
If the bar is set low, the variables do become "don't cares"..... The problem is there will be someone who will think the design is inadequate.
If the bar is set high, the variables becoming "don't cares" is next to impossible, in my humble opinion. This is why I think listener feedback is paramount to a good audio design. Until we can attain a more-complete picture from a measurements and specs standpoint, the best yardstick for performance will indefinitely be the collective satisfaction of the end users.
Edits: 06/25/09
"It isn't just the competence, or lack thereof of the designers. Home audio is one of those pathological cases which superficially seems trivial, and yet isn't. "
I don't think it's just home audio..... It's **all** audio....... If you think the stuff designed for the studio is of more competence, I'd kindly but strongly disagree. (I personally think Pro Tools is the single biggest monstrosity of a design ever conceived.) Just look at the horrible recordings that have been put out in recent time.
> Well, I don't have much exposure to that field but I think it's better, at least they are using balanced cables! The main reason I usually say 'home audio' is that that's what I'm familiar with.
"While almost anything thrown together by almost anyone will work, designing a product that really works well, i.e. to the point that it is effectively transparent to the ear, is another matter. Here are a few reasons that come to mind..
1. The lack of systems engineering.
-The home audio system topology wasn't designed, it just happened."
Systems engineering would force a home audio system to be of a "all in one" type design..... Unless every designer agrees upon what the system ought to be, this "lack" will go on indefinitely......
> Nah, I don't think so. The main thing that's wrong is the interfaces are poorly specified especially with respect to impedance and susceptibility.
I personally don't think this facet of engineering is any more of a problem than other facets of engineering.
> Boy I do, look at the stuff people hang onto their systems trying to get them to play well together.
"2. The lack of meaningful standards.
-To put it bluntly, it's not important enough to governments or industry."
It shouldn't be important to government, unless public safety is an issue...... (This is why we have UL standards, by the way.)
> It depends upon your view of government. Ours does have some such as FCC part 15, Europe has more. I've come to view some of the CE requirements as a good thing. It makes my job harder but really does result in a sturdier design.
I do agree in regard to industry...... But it would require an across-the-board agreement amongst many backgrounds, so even if such objective is sought, the chances for successful implementation would be very slim.
"3. Unusually wide bandwidth.
- Three to four decades of signal bandwidth is huge."
Not since digital audio has hit the scene. Bandwidth is limited to 22.05 kHz. And because of that, bandwidth in line and power amplification is no longer so important. So I strongly disagree here.
> On the outside that limitation reduces the bandwidth by less than an octave.
I also disagree in regard to bandwidth being a problem, unless it's so wide, it becomes susceptible to RF interference.
> The wide bandwidth makes the signal more susceptible to problems, especially due to passives such as skin effect and core saturation.
"4. In-band power.
- Having the 60Hz power supply and it's main harmonics where we hear is bad."
The only solution to this is battery power..... Jeff Rowland, a so-called "home audio" manufacturer, has undertaken such approach.
"5. Extreme user sensitivity.
- Reducing distortion to where you really CAN'T be aware of it is tough."
The user sensitivity has always been "extreme." The problem is too many in the design community are trying to convince the masses that associated discomforts should be tolerated to a degree or that the sensitivity is overrated. This is a big reason why audio design has been disappointing, in my humble opinion.
> Agreed.
"6. Conflicting design approaches.
- Nowadays this is less of a problem due to switchers and mixed-signal designs, but traditionally audio guys were clueless about RF and the major rules of thumb are in conflict. It's hard to both star ground and maintain a Faraday shield."
It's not difficult to make a star ground and Faraday shield...... It's that the latter has been deemed unimportant. Whether it is or not is subject to debate, but I will say the internal RFI generated from digital devices has rendered the Faraday shield ineffective. Although it should still be used on purely analog components like phono stages.
> I think it is. Basically you want the shield to ground to the box for RF but to the board for audio so if you do a good job you end up with a little of each but don't get the best of either
In regard to "clueless about RF", this is a problem for most designers across the board, not just home audio. The RFI generated by digital devices has changed everything.
Conflicting designs in itself is not an issue. The might both be competent, they might both be incompetent, and anything in between.
"Enough of that. It isn't trivial, there is no agreement on how good is good enough,"
Now here you hit on an issue. When in doubt, raise the bar, not go the easy route and think a lesser design might still fly. This IMO is a big problem in modern audio design. The bar simply hasn't been set high.
"what factors are important and how they are to be measured and weighted, or what the worst-case environment is that must be accommodated. The latter includes vibration, equipment interface, power supply, EMC and operators both deliberate and inadvertent. I'm trying to think if I know of anybody whose toddler HASN'T put a PB&J sandwich into the VCR."
Or oatmeal.
"But... I'm with Tom. The obvious goal is to design gear where all of these variables become, as much as possible, 'don't-cares'."
If the bar is set low, the variables do become "don't cares"..... The problem is there will be someone who will think the design is inadequate.
If the bar is set high, the variables becoming "don't cares" is next to impossible, in my humble opinion. This is why I think listener feedback is paramount to a good audio design. Until we can attain a more-complete picture from a measurements and specs standpoint, the best yardstick for performance will indefinitely be the collective satisfaction of the end users.
> Well, it just takes too long to consider every possible aspect of every design. At some point you have to develop a good feel for what you can get by with. Sometimes you are wrong which adds to your knowledge of what's important.
I don't know if this format will work Todd, I'm using a WP that I'm not familiar with so I apologize in advance if this is confusing.
Still using CDex? I'm really pleased that you tried it and that it worked for you, it does for me. Now there's something. You are a SW guy aren't you? Why does it sound so good?
Rick
Recently I witnessed an improvement in sound with usage of an aftermarket power cord on a SS power amplifier (replacing yet another aftermarket power cord) that rather shocked me.The main reason for the shock was largely due to the fact that the effect ran counter to my experience, that power cords seem to make the least impact on SS power amplifiers vs. source/preamp/low power gear; regardless of how counterintuitive that may seem.
The second reason for the shock was due to the particular SS amplifier, a Bryston 4BST, an amplifier which along with its SST sibling has long ranked in my most hated list. The ills associated with the 4BST/SST, what I would call electronic sheen (a subjective description) seemed to me to have vanished!
Now do we have an engineer present who would like to step up to the podium and propose that the power supply design of a Bryston 4BST is inadequate? I rather doubt we'll witness such at thing. The point is that one can lean on one's engineering principles/background, bring in ideas from other fields and what-not, but the rubber hitting the tarmac is a different story altogether.
---
OH, having had a peek inside a Bryston 4BST ... the one I had on a home trial, that incidentally embarrassed itself against the Kenwood L-07M monoblocks (late 70's production) I was then using ... I was a bit surprised by what I thought was relatively modest sizing of the capacitor banks. Certainly many other current designs provide a heck of a lot more for the power rating. Still from an engineering perspective no doubt the sizing is more than adequate; it's true that (per side) storage *was* greater than what was in the much older L-07M.
(The L-07Ms had had their captive zipcord replaced with garden variety outdoor (orange) extenstion cord (that's how they were when I got them) and IIRC I used the stock power cord provided with the Bryston. At that time I likely wouldn't have had anything much better lying around to try on the 4BST).
Everything matters, don't forget to tweak your placebos!
Edits: 06/25/09
Your findings raise a more-important point.......
Bryston amplifiers have often been deemed "properly designed" by the so-called "scientific" audio community, in regard to how little effect audio cabling should have on sound if interfaced to such designs.
But based on your findings, even this respected amp line is apparently affected sonically by cabling. (I've always suspected this would be the case. I've never come across an amplifier that was immune to cabling.)
So the term "properly designed" is nothing more than an ideal that seems to **never** exist in reality. Yet this idealistic term is often mentioned as factual basis for why audio cables don't or shouldn't impact sound.
It does seem to be mostly semantics doesn't it. In fact as best as I can tell at least one of our resident "engineers" (Don Till) seems to have taken it to a declarative/definition level by essentially stating that if an amplifier's performance varies with usage of power cords then by definition its power supply is not "well designed"... and it seems he's more than willing to include Bryston in the poorly designed group (assuming there's any truth to my report of course!).
So isn't that so very clever! Power cord are hence allowed to effect performance along with a nice tidy reason for why this is the case... our engineer sleeps well at night and all in the universe is in order!
LOL
Everything matters, don't forget to tweak your placebos!
"So isn't that so very clever! Power cord are hence allowed to effect performance along with a nice tidy reason for why this is the case... our engineer sleeps well at night and all in the universe is in order!"
And are you suggesting things are somehow different? As if there aren't tradeoffs made in every component design at every price point. Some of us might immediately condemn a slight high frequency roll off or minor transient shaping at the same time ignore, or even worse claim higher resolution from components displaying problems protecting itself from being influenced by external factors.
deny my call on your definition/declaration!
LOL
Everything matters, don't forget to tweak your placebos!
Why should I deny it? If I establish the level of acceptable performance for a well designed component as being not audibly effected by external influences in normal operating conditions it's not like I'm setting a high bar. Or am I?
And just to clarify this. I don't believe the Bryston as you describe it is working to spec (as advertised), just like my Raysonic CDP that greatly benefits from an "better" power cord. It's not like I think the sound of these things get betters than advertised when external power cords or conditioners are applied. I think only then do they deliver on the promise of the original purchase.
It may be that the particular instance of the amplifier was defective. This could be the result of a component or wiring failure. Or perhaps a batch of instances were defective. This could be the result of Manufacturing performing some "value engineering".
A company that sold audio kits many years ago used to do this kind of "value engineering". The purchasing agent would make "minor" substitutions of component values or tolerances to reduce parts cost. I heard this from the purchasing agent's son.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Of course, there's always a possibility of amplifier being defective - it's just that being affected by power cord change is in no way or shape the sign of "defectiveness".
More experience with resolving equipment, and less preconceived notions in the head - that's best possible cure against such "defects" in amplifiers.
Actually I was quite serious.
I have had a defective amplifier, and it was in the power supply, no less. As it turned out, the defect wasn't at all subtle—it resulted in a moderately loud hum in one channel. The amplifier had separate output filter capacitors for each channel and one of the four had gone bad. The manufacturer had gone out of business and there was no direct replacement available at "You-do-it Electronics" so I substituted four new capacitors of slightly larger size, which fit only when held in by duct tape. Interestingly enough, the result was a significant improvement in sound over what it had been prior to the failure. I presume that the original capacitors either lacked sufficient energy storage capacity when new, or perhaps had gradually lost their capacity over time.
Had the failure been in the input power line filter then I might not have noticed it, at least not until I moved into an environment with lots of EMI. At that point, I might have effected a sonic improvement by replacing the defective internal components or by attaching an external power cord that provides rejection.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
In this instance I have to rely on the veracity of bjh's observations - ie. they are presented in such a way that indicates it's not a one time observation and have been repeatable in a variety of different situations. At least that was my take on the wording of his opinion of Bryston equipment.
In my normal work environment when issues come up the first thing I like to do is to witness them. Whether this occurs in the lab or I reproduce them at my desk kind of depends on the importance and severity of the issue.
I agree with your take it could be a defective unit and the defect could be for one of any number of reasons. However and again - the comments I'm relying upon indicate this is the normal performance one achieves from the Bryston amplifiers in question.
Often when I get to the lab or reproduce the issues as described by a customer, technician, marketeer or even other engineer the issue is actually quite different than the description. I'm giving bjh the benefit of the doubt for the purposes of this conversation.
.
Everything matters, don't forget to tweak your placebos!
by members of self-proclaimed "scientific" community, for effects of substituting different power cords. The same as with, for instance, Van Alstine DAC, that according to manufacturer, was supposed to be immune to differences between transports - but wasn't.
Why would the pseudo-scientific community test for a foregone conclusion??? They might discover the world isn't flat!!! How can you remain an audio regressionist if you test things all the time???? :)
"Now do we have an engineer present who would like to step up to the podium and propose that the power supply design of a Bryston 4BST is inadequate? I rather doubt we'll witness such at thing.
Given that the amplifier as supplied merits the following comment when an after market power cord is installed -
" The second reason for the shock was due to the particular SS amplifier, a Bryston 4BST, an amplifier which along with its SST sibling has long ranked in my most hated list. The ills associated with the 4BST/SST, what I would call electronic sheen (a subjective description) seemed to me to have vanished!"
I would say yes the amplifier power supply filtering is inadequete, based on your comments for the environment in which you made your observations. I can't believe the designers of this amplifier intended the "electronic sheen" and I hardly doubt it takes an experienced golden eared trained listener to hear it.
But alas if one can buy a Bryston power line conditioner or any number of after market power cords to solve the problem who's to complain?
Personally this is the kind of crapola that long ago turned me against the marketing vehicles posing as audiophile magazines willing to tolerate such performance deficiencies to further their vested interests in growing the industry.
Sure power cords and conditioners can and do often make a tremendous difference and most anyone should be able to hear it.
Communications and test equipment owner's wouldn't tolerate for an instant such haphazardly designed products. Funny how audiophiles and the industry in general seems to tolerate it at the same time marketing spending for the work arounds as ways of bringing home improved performance.
I would have added an exception for you.
Everything matters, don't forget to tweak your placebos!
"The point is that one can lean on one's engineering principles/background, bring in ideas from other fields and what-not, but the rubber hitting the tarmac is a different story altogether."
No it's not a different thing, not at all. Whether possibilities jump out at you or need to be sought after does somewhat depend upon what 'other fields' you have been plowing.
So, the power cord changes the sound, what does that mean and to whom does it mean it? Does the product no longer meet it's specifications? Probably not. Does it mean that the specifications are inadequate? Maybe.
Most likely if there is an error it's that in the internal product requirements. Either what you are experiencing was regarded as insignificant or whatever is causing it was missed completely. You can usually rely upon products meeting their production specifications, what's a lot iffier is relying upon those specifications to predict the outcome for all users.
"I was a bit surprised by what I thought was relatively modest sizing of the capacitor banks."
Physical size? Capacitance? ESR? Net energy storage? Capacitors have come a long way the last decade, especially in terms of HF ESR. How much capacitance you need depends upon the headroom and PSRR of the amplifier.
One of the things that's fun about this hobby is all of the counter-intuitive things you find that can affect the sound. I've had rum luck predicting whether I'll like the sound of something without listening to it. Size, color, cost, weight, brand et al are poor predictors. How can you tell a "better" power cord without trying it in a particular application?
Rick
> > "The point is that one can lean on one's engineering
> > principles/background, bring in ideas from other fields and what-not,
> > but the rubber hitting the tarmac is a different story altogether."
> No it's not a different thing, not at all. Whether possibilities jump
> out at you or need to be sought after does somewhat depend upon
> what 'other fields' you have been plowing.
If the exposure to 'other fields' merely informs to discount anecdotal evidence (power supplies are adequate, hence reports are fictions), or dissuades investigation (power supplies are obviously ill-designed, not worth bothering with), which seems to me to be just barely concealed (intentional or otherwise) message(s) in tomservo's post, then I would maintain the 'other fields' applicability is null.
I won't bother with the other points as they seems to me more than a little argumentative oriented.
Everything matters, don't forget to tweak your placebos!
I don't understand where you are coming from. This is a discussion, not an argument. I didn't see Tom discounting the issue as much as advocating that it can be fixed. I'm essentially on the same page but in trying to address your question of whether hearing a difference due to changing a cord meant a defective power supply tried to broaden it out to examine reasons both social and technical that they might especially at the system level even if the individual components were within spec.
Sorry if I waxed too philosophic, no harm intended.
Rick
"things like power line conditioning and power cords *do* often still make a difference. "
Yes, it's true perhaps but when it's true then also it is evidence that the power supply design is incomplete.
Noise "can" be a problem if your design doesn't deal with it, then an external bandaid can help beyond decoration.
Since it is possible to make power supplies which are extremly immune to huge line noise, possible to make radio transmitters with sensitive audio circuitry, even possible to make sensitive electronics operate in close proximity to an xenon arc lamp, what would be the reason (other than cost or knowledge) not to design for noise immunity like that in modern hifi gear?
This problem is not new either, one couldn't design a tube amplifier in the old days without addressing RF and noise.
Most output tubes and all small signal tubes would work perfectly happily up to Citizen's band (27 MHz) if allowed to, not like transistors which have vastly lower open bandwidth.
In the old days there were mare severe sources of noise too, in the last 20 years these sources were replaced to permit the cell phone and wireless era high up in frequency.
My point is as a designer, one is left thinking the job is not done if an external shield / AC cord etc actually changes the operation.
Think about it this way, It is "foolish engineering" to leave the proper operation of a circuit or system to depend on having "the right" kind of AC, especially since one can remove that issue at least over some range with proper design.
Testing the actual operating voltage range and tolerance / immunity to input distortion / noise is normal stuff, at least when making test equipment.
Possible reasons for the way it is;
Audio design, especially power analogue circuitry, is a much much smaller business than "test equipment", fewer Ham's and DIY'rs now in the field, who are good self taught designers and perhaps the very presence of the "mystery of the magic cord" and such enhances part of the industry's image and romance among the buyers
Just a wild guess.
..., in your opinion, designed power supply, that is immune to power cords.
Of course, with details of the system this piece of equipment was tested in.
Forgive my scepticism - but I've never faced one since my system became more or less resolving. However, I can see that to be the case in the context of cheap receiver and CD changer, connected to $100 speakers - but the reason, obviously, would be quite different from power supply being designed "properly".
Sure, here are two, old and new, A Xilica 4080 speaker controller / processor operates over a wide range of input voltages, has no sound, or audible pickup when used near xenon and old florescent lighting or next to switching power supplies and amplifiers.
It’s balanced inputs make concerns about exotic cables irrelevant and the market and sales of exotic cables is vastly smaller by percentage in pro.
A McIntosh mx110 tube pre-amp / tuner also had a huge tolerance to RFI and EMI noise and could be used next to the room with an RF induction heater.
In general tube gear, including the tube amplifiers from Grommes where I worked in the 70’s, were very tolerant of line and radiated noise but much less so on the range of line Voltages.
Lastly an example of a sort of audio situation I had to resolve personally.
I was given the task of re-designing and then building and testing the control electronics for an Acoustic levitation system which was to be flown on the shuttle but first on sounding rockets.
The science problem driving this being that there were many materials which reacted with the container when melted or required such a high temperature that there were no containers available.
The solution was to use high intensity sound to position a sample in the middle of a really hot furnace, to melt and cool the sample without contact.
The existing sound source had a capacitive pickup, like a condenser microphone, which was charged to 200Vdc.
The sound source was a resonant bar of titanium, the pickup’s job was to pick up the tiny signal from the vibration at 16KHz and use the pll circuit I designed to lock on to the resonance, keeping it in tune and at a constant amplitude.
This had to be done on shuttle power, which could vary from 24 to 42Volts (28VDC nominal) with a boat load of noise spectrum up to low RF.
Our experiment power was set to 100Amps so the furnace modulator (4 phase pwm) had to monitor a current shunt to regulate at no more than 100 Amps while heating.
Here is a link to that stuff, now 20 years ago.
http://www.springerlink.com/content/42375j4148345603/
Anyway my point was that even when dealing with the most sensitive signals like a “naked” condenser microphone, buried within an extraordinarily electronically noisy environment, you can still engineer around it, if doing that is part of the task.
Unless there are unusual circumstances, the level of conducted and radiated noise in the home is certainly much less than in industrial and many commercial uses of electronics, including audio.
Lastly, keep in mind that in addition to any real change electronically or not, other things can also effect ones perception of a given event.
A simple test which may be useful to help in seperating these.
Sit down and listen back and forth between the two cables which show the largest difference. Pick music that makes the difference obvious as possible and go back and forth.
When you feel it’s the right time un plug them, have a friend come in and have them pick one of the two and plug it in and you listen again, now not knowing which cable it was.
Have the friend switch back and forth making sure you can’t see and he doesn’t tell you which one is in use.
The results of these fall one of two ways generally.
Most often, the audible difference is smaller to much smaller or even gone when you don’t know which is which and you only use your ears.
If there is a difference even if small this way, without prior knowledge, then you are on to something in the engineering side that can be tracked down to a source, ideally before it is sold as a product.
If not, don't feel bad, in fact your in good company.
In the recording and mixing community there is a story told to remind themselves they are not infallible even if they do it for a living.
It goes like this, the engineer spends 10 min doing minute tweaks on an eq or processor strip getting the sound "just right".
Then when sitting back to enjoy, notices the "bypass" button is / was pressed the whole time.
To a very real degree, we hear what we want to hear and only part of that is related to electrons etc.
You're right, but it was not a great sounding piece of gear. Rolled off on the top end with a most definite lack of detail and information.
Therein lies a major issue with audio gear. While test gear is often oriented to optimize one or maybe two specific parameters, audio gear has a range of parameters to satisfy. The goal is not to meet a standard but to surpass those standards. Considering the wide bandwidth, the dynamic range desired, the great mix of frequencies and levels involved in any mix, that is a pretty tall order. Then couple that with the various range of human tastes.
Audio gear is geared to extreme sensitivity. Very often our test gear is not even designed to measure such parameters which can be detected by the human ear. As an example there is the rather groundbreaking work done by Matti Otala concerning TIM distortion, which was relatively unknown until he published his works. If test gear exists it is often astronomically priced. I recall a Rhode and Schwartz real time analyzer used by one company to measure a particular parameter in wire construction which cost them at the time $100K and of which only five units in the world had been manufactured.
In many pieces of audio gear you sacrifice one aspect of music to optimize another. In many instances what is theoretically negligible can be audible, despite engineering theory.
I recall one manufacturer displaying a prototype of a preamp and commented that his new design using the identical layout and parts should sound better than his original which had multiple individual phono sections. His reply that from a theoretical point of view there should be absolutely no difference as the power supply was sufficiently large to exclude any current draw differences even if all the sections were running (they were not at the time). Yet a direct comparison revealed, obviously, that there was a sonic difference.
Declaring that human perceptions can vary, while very true, ignores the basic fact that some listeners can hear certain changes. You can cater to the lowest common denominator or you can cater to the extremely discriminating.
You can be happy with the relatively lossy mp-3 player or you can demand the very high end piece of audio gear. Both can offer great satisfaction to many users. But just because the listener with the poorer component is happy does not necessarily mean that anything "better" is a figment of the user's imagination.
Let's face it: there are huge ranges in human perception and that is simply part of the challenge. I once placed five different types of hook up wire in my preamp's five inputs. There was enough differences so that even the two inch length made a difference, however, subtle you may believe it to be. In a system I was familiar with I could consistently identify each input even in a blind test. I do not claim "golden ear" status, but I have spent an inordinate amount of time actually listening to music, critically.
While I barely made it through aural training classes at the local university, continued listening in the manner I was taught can reveal certain aspects which many others do not hear. It has nothing to do with the condition of your ears, but more to do with the mind-ear connection. In doing research on hearing, I am consistently struck by the fact that any of the senses can be trained if you embark on a program to do so.
Think of it in terms of the aficionados of wines and how much practice they have to go through in order to become an expert. If you're into video games, think of how much time you need on a particular game in order to excel at it. Still in music, it is the subtleties which define the a great performance or a great virtuoso. A great performer can make even a student model instrument sound decent, but he will do much better with a a great one. The pursuit of the subtleties in music is what drives many to "better" audio gear. If not, the world would be happy with a transistor radio.
Stu
You basically said the same all over again... got it the first time, doesn't change the situation for me anyway.
Everything matters, don't forget to tweak your placebos!
Ok, just wanted to be clear on how that works technically.
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