Hi,
In other words, all consumer gear, expensive or cheap, minus class D amplifier outputs which have these chokes, though not to protect them from RFI, but to protect the rest of the world from the RFI they produce...
This I would argue is debatable. There are options other than figure 8 that do better, even for RFI rejection. And it IS possible to design LCR into cables, be it to have mysterious boxes or to have a real RFI suppression filter or replacement for the build out network integrated into the cable (ala UBYTE Speaker cable).
Ciao T
In other words, all consumer gear, expensive or cheap, minus class D amplifier outputs which have these chokes, though not to protect them from RFI, but to protect the rest of the world from the RFI they produce...
This I would argue is debatable. There are options other than figure 8 that do better, even for RFI rejection. And it IS possible to design LCR into cables, be it to have mysterious boxes or to have a real RFI suppression filter or replacement for the build out network integrated into the cable (ala UBYTE Speaker cable).
Ciao T
I'm sure it will come as a reassuring relief to those who make and sell these expensive product that there is still a market for them even among DIYers who should know better. It's sad when you hear it from an electrical engineer. Makes you think the value of an engineering education has somehow evaporated and has little impact against slick advertising that flies in the face of what they should have gotten for their efforts to learn.
Sorry, I don't know why I said toroidal chokes, I actually meant ferrite beads. Bit of a brain slip there.
The sort that are slipped over the centre wire directly at the input/output sockets on well designed equipment, and are pretty effective at eliminating RFI sensitivity in audio equipment, especially when used together with a small value shunt ceramic disc cap.Unfortunately a lot of consumer grade equipment don't bother with them, presumably due to penny pinching, but I have modified a few pieces of equipment this way if they have been overly sensitive to RFI.
You have made the most sensible observation so far in this thread. Kudos to you!
Back in the early 70's I had a crappy receiver, and lived very close to a 50,000W transmitter. No RF interference as far as I know.
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During my career I have probably purchased close to 2 million dollars worth of wire of almost every possible description. My views are not only the product of my education but of manufacturer's reps including from Belden. My largest single order was for $330,000 from the Habia Cable Company in Ronkonkama Long Island. 330 Spools of 1700 foot put ups of RG62 and 59 spools of 1700 foot put ups of 25 twisted pairs both types in teflon. This for the main interbuilding connections for a synchronous (Ungerman Bass) and asynchronous (Micom) data network at a critical node at a Bell System software development facility in Central NJ in the mid 1980s. BTW, the wire quality was outstanding, not a single defect in that huge order.
UK, Italy, USA
As a systems engineer I have also purchased great quantities of all types of cable, copper & fiber, for airport communications systems. I used Belden as well as General Cable as main vendors. I also have not have any instance of defective materials.
For my HT System, I wanted as much SQ as I could get for rock bottom prices. So, what I wound up using for HT speaker internal wiring was landscape cabling - it's solid copper 18AWG in pretty much however many conductors you want with each one available with polyethylene insulation and with an overall PVC jacket. I needed and found a cable with a total of 8 conductors between the xover at the base and the nine drivers which were mostly located toward the upper portion of each speaker.
Between my HT amp and the speakers which require runs of up to 50 feet or so to snake around furniture/under the floor & back, etc in my 17' x 25' great room, I wound up using 12/2 Fire Alarm Cable. It's not really that different than similar gauge THHN AC wire electrically, but it does come pre-twisted, color coded and with a cool red PVC jacket. Plus it won't go green with oxidation on you after a few months like most non-tinned multistrand cable does and when that happens the cable is sonically shot. Even un-oxidized, the interstrand rectification smears significant detail, IMO. So I accepted a bit of HF rolloff due to skin effect (with bonus RF attenuation) to preserve most all the inner detail available in the DTS-HD Master/Dolby True HD/Linear PCM 24/96/192 soundtracks from the amp terminals to the drivers.
My 56 year old ears thank me for this
Between my HT amp and the speakers which require runs of up to 50 feet or so to snake around furniture/under the floor & back, etc in my 17' x 25' great room, I wound up using 12/2 Fire Alarm Cable. It's not really that different than similar gauge THHN AC wire electrically, but it does come pre-twisted, color coded and with a cool red PVC jacket. Plus it won't go green with oxidation on you after a few months like most non-tinned multistrand cable does and when that happens the cable is sonically shot. Even un-oxidized, the interstrand rectification smears significant detail, IMO. So I accepted a bit of HF rolloff due to skin effect (with bonus RF attenuation) to preserve most all the inner detail available in the DTS-HD Master/Dolby True HD/Linear PCM 24/96/192 soundtracks from the amp terminals to the drivers.
My 56 year old ears thank me for this
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You bring up an important quality cables may have: to consist of very fine strands. There are no audible differences with a solid core, i.m.w.c.p., but a cable that is mechanically well made (that is flexible and will allow to be bend in short radii without being damaged) will in the end also be better sonically. The reason is that stiff cables tax the connection points to amplifier and loudspeaker more than flexible cables do. Since these connection points are typically mechanical in nature, this might lead to bad connections over time, since things get shifted around. By the same token, this is an argument not to use overly dimensioned and thus weighty cables. There definitively is an optimum point, where the lower DCR of a thicker cable is outweighed by its mechanical disadvantages.
So, when buying cable, think about the mechanics of the situation. For normal living room use, I would any time prefer 2 mm fine stranded over 2.5 mm divided over 7 strands. @ Bill Poster: That does not have to cost 10 Pound per meter, but it is just very hard to find. Certainly for free.
Hi,
Actually, I would think as this is DIYA most make their own cables, especially as it is so easy.
So the question what makes "good" cables remains and there is no need to get all huffy and puffy about someone making obscene amounts of money (next to making money of russian oligarchs and chinese nouveau riche who buy HiFI's as decoration making a single buck of a DIY'er is really hard work)...
I do use fairly exotic cables (home made of course, with that even goldplated silver wire in air dielectric is very affordable and preferable to using cotton as some insist on doing) and I have found that audible differences do exist among different cables.
I am unsure if my gold-plated silver special is really better than (say) the better RG-XXX/Mil types with silverplated double screens as interconnects, but I like to use them anyway, because I have them. Same for my SCSI III based speaker cables, which may not be better than Cat 5 based stuff, but I have them and they look cool.
TBH, I really do not like the fact that cables make a difference, but I am even more appalled that people who should know better, keep trying to talk these differences away, especially those difference that are trivial to explain using basic electrical theory...
Maybe it has to do with an incident in my past, when many moons past I was living in a little charming country behind seven seas, seven mountains and one large wall, at which any that wished to leave said charming little country for the appalling capitalist west after having been taking in by all the glitzy slick advertising where promptly and summarily shot dead to protect them from such ignoble and terrible a faith...
By day I worked in a steelwork in the process control electronics section. By night I worked as sound engineer with a band (and DJ). As customary in those parts at the time, the band owned their own PA System, or more precisely, I owned most of it.
One day I needed a new, quite long microphone cable and lacked the time to drive to the only shop in the whole country that had the necessary imported stuff for Dollars (we bought our speaker drivers as well as a lot of other stuff there).
So I liberated some cable intended for sensors (to be precise, strain gauge sensors) from a large reel we had (cables kept getting damaged by liquid steel when people where careless, which they where often) and stole the XLR cables of some short old cables we no longer used. After a few gigs testing reliability I put the cable on our singers Mike. Our singer quite liked that cable was a little stiffer than the normal stuff (she liked a lot of things a bit stiff I guess) and a fetching bright orange.
For month afterwards I was really foxed that the singers mike sounded different, not neccesarily better or worse, but different and I had to compensate the settings for the mix subtly from what I normally was able to use.
I never in my dreams thought to consider the cable the culprit, after all, it's just a cable and it was similar in geometry, much better shielded than the normal mike cable I used everywhere and should really be no worse (maybe it was actually better, but this too I could not conceive at the time).
One night I put different cable on that Mike, I cannot remember why, but bang, the original sound was back. So I thought I must have been imagining things (I still had not twigged that I had in fact changed cables), but when at the following gig thing where back to different, so I dug down and finally identified the cable as culprit.
FWIW, the "offending" cable used silverplated copper conductors in some PTFE like stuff, a little softer than PTFE, it was twin twisted pair, had several rope inserts to make it more resilient when stretched, had a conductive rubber layer over this against triboelectric effects and used a foil screen with a dense silverplated copper screen, outer jacked was silicone rubber.
The normal cable was plain copper twin twisted pair with PVC insulation and a not too dense copper screen. Length was similar and >> 10m, but I would not say identical to the cm.
Mike was a Beta58 from Shure, mixing desk was an east german design which included exemplary RF Filtering and transformer inputs for all inputs. Mikes and instrument feeds connected to a stagebox to which a "snake" made from shielded, gel-filled telephone cable was connected with a multi-pin plug (same plug was also fitted at the Mixer flightcase), the snake was either 25m or 50m.
Since this very annoying cable demonstrated to me so clearly that the "it's all wire" view I learned at university clearly did not cover all there was between heaven and earth, I have held a solid disrespect for any position that attempts to maintain this overly simplistic and inaccurate view as true.
I have in the intervening decades learned a lot about why things that should, on casual inspection with EE's eye, not sound different actually do so anyway. And rarely do I have to accept that the reasons are inscrutable or require very esotheric explanations...
But for those who want to wilfully blind, please keep it up.
Ciao T
PS, FWIW, when the reel at work was used up (I liberated no more of this one cable of course, I might have even taken the cable back as I did not want it) the company declined to buy a new imported reel for these ridiculous levels of money and we used afterwards locally made stuff that looked identical enough.
After month of ongoing minor but annoying and costly malfunctions in the systems that had been patched with this "cheap" cable the US Supplier of the whole system was called in. They looked around and found not much, until they looked at the patched cables and asked "WTF is THAT".
The correct cable was purchased and fitted and was well again in this little corner of the world, untill people made a revolution a few years later, imported capitalism and the steelwork shut down leaving thousands out of work, but that, as they say is another story.
Actually, I would think as this is DIYA most make their own cables, especially as it is so easy.
So the question what makes "good" cables remains and there is no need to get all huffy and puffy about someone making obscene amounts of money (next to making money of russian oligarchs and chinese nouveau riche who buy HiFI's as decoration making a single buck of a DIY'er is really hard work)...
I do use fairly exotic cables (home made of course, with that even goldplated silver wire in air dielectric is very affordable and preferable to using cotton as some insist on doing) and I have found that audible differences do exist among different cables.
I am unsure if my gold-plated silver special is really better than (say) the better RG-XXX/Mil types with silverplated double screens as interconnects, but I like to use them anyway, because I have them. Same for my SCSI III based speaker cables, which may not be better than Cat 5 based stuff, but I have them and they look cool.
TBH, I really do not like the fact that cables make a difference, but I am even more appalled that people who should know better, keep trying to talk these differences away, especially those difference that are trivial to explain using basic electrical theory...
Maybe it has to do with an incident in my past, when many moons past I was living in a little charming country behind seven seas, seven mountains and one large wall, at which any that wished to leave said charming little country for the appalling capitalist west after having been taking in by all the glitzy slick advertising where promptly and summarily shot dead to protect them from such ignoble and terrible a faith...
By day I worked in a steelwork in the process control electronics section. By night I worked as sound engineer with a band (and DJ). As customary in those parts at the time, the band owned their own PA System, or more precisely, I owned most of it.
One day I needed a new, quite long microphone cable and lacked the time to drive to the only shop in the whole country that had the necessary imported stuff for Dollars (we bought our speaker drivers as well as a lot of other stuff there).
So I liberated some cable intended for sensors (to be precise, strain gauge sensors) from a large reel we had (cables kept getting damaged by liquid steel when people where careless, which they where often) and stole the XLR cables of some short old cables we no longer used. After a few gigs testing reliability I put the cable on our singers Mike. Our singer quite liked that cable was a little stiffer than the normal stuff (she liked a lot of things a bit stiff I guess) and a fetching bright orange.
For month afterwards I was really foxed that the singers mike sounded different, not neccesarily better or worse, but different and I had to compensate the settings for the mix subtly from what I normally was able to use.
I never in my dreams thought to consider the cable the culprit, after all, it's just a cable and it was similar in geometry, much better shielded than the normal mike cable I used everywhere and should really be no worse (maybe it was actually better, but this too I could not conceive at the time).
One night I put different cable on that Mike, I cannot remember why, but bang, the original sound was back. So I thought I must have been imagining things (I still had not twigged that I had in fact changed cables), but when at the following gig thing where back to different, so I dug down and finally identified the cable as culprit.
FWIW, the "offending" cable used silverplated copper conductors in some PTFE like stuff, a little softer than PTFE, it was twin twisted pair, had several rope inserts to make it more resilient when stretched, had a conductive rubber layer over this against triboelectric effects and used a foil screen with a dense silverplated copper screen, outer jacked was silicone rubber.
The normal cable was plain copper twin twisted pair with PVC insulation and a not too dense copper screen. Length was similar and >> 10m, but I would not say identical to the cm.
Mike was a Beta58 from Shure, mixing desk was an east german design which included exemplary RF Filtering and transformer inputs for all inputs. Mikes and instrument feeds connected to a stagebox to which a "snake" made from shielded, gel-filled telephone cable was connected with a multi-pin plug (same plug was also fitted at the Mixer flightcase), the snake was either 25m or 50m.
Since this very annoying cable demonstrated to me so clearly that the "it's all wire" view I learned at university clearly did not cover all there was between heaven and earth, I have held a solid disrespect for any position that attempts to maintain this overly simplistic and inaccurate view as true.
I have in the intervening decades learned a lot about why things that should, on casual inspection with EE's eye, not sound different actually do so anyway. And rarely do I have to accept that the reasons are inscrutable or require very esotheric explanations...
But for those who want to wilfully blind, please keep it up.
Ciao T
PS, FWIW, when the reel at work was used up (I liberated no more of this one cable of course, I might have even taken the cable back as I did not want it) the company declined to buy a new imported reel for these ridiculous levels of money and we used afterwards locally made stuff that looked identical enough.
After month of ongoing minor but annoying and costly malfunctions in the systems that had been patched with this "cheap" cable the US Supplier of the whole system was called in. They looked around and found not much, until they looked at the patched cables and asked "WTF is THAT".
The correct cable was purchased and fitted and was well again in this little corner of the world, untill people made a revolution a few years later, imported capitalism and the steelwork shut down leaving thousands out of work, but that, as they say is another story.
It was an interesting and peculiar thing. My plant engineers asked me to investigate a peculiar problem. A contractor had installed additional smoke detector heads to existing strings connected to a Gamewell fire alarm panel. The contractor had spliced solid copper to existing stranded wired. There was a lot of RF noise generated in this building, it was a communications research building. The zone alarms where this had been done were all in alarm, that is nuissance alarms. The system worked at 0-5 volts DC. The explanation was that the union of the stranded and solid wire acted as an RF diode detector and the resulting detected noise was sufficient to trigger the modules to go into alarm. The solution was to connect a small (I think about .047 mfd) capacitor across the input of each alarm. This acted as a shunt at frequencies where the noise had been detected but as an open circuit at DC where the system operated. I probably would have doubted this was the likely cause if I hadn't seen it for myself.
I don't think you read what I said or perhaps you didn't understand it. The only valid test of a cable's performace is how it behaves in comparison to a shunt. Any deviation from a shunt no matter how desirable the result may seem subjectively indicates a defect in the wire. It is the cheap wires that work perfectly, the audiophile wires that are defective.
Hi,
No cable exists that behaves like one. We can argue this endlessly.
I find your rectification story actually a lot more interesting than what you argue in this post.
I am interested in the real behaviour of imperfect items in an imperfect world. So comparisons to abstract ideals are meaningless to me, but comparisons between two imperfect item items to find which is more suited to the task is VERY meaningful to me personally.
No, all wires are defective by your definition, as non is an ideal shunt, in fact, an ideal shunt does no more exist than any other ideal anything, except perhaps in the mind of the divine, where the ideal shunt joins the ideal chicken coop, with ideal Chickens and no doubt ideal Chicken Excrement.
So we are back to select which wire defects we have least issues with. And surprisingly of course, we are back to basic electrics and any polemic about cheap or expensive, high end or low is meaningless in this context, as it has no relevance to the topic. So why insist on it?
Wires make a difference, deal with the facts.
If anyone does not like the facts, deal with them by going and stick the head in the sand, nobody forces anyone to take note or action, sticking the head in the sand has apparently been a good evolutionary strategy for the Ostrich for many years.
As I said, those who wish to remain wilfully blind, feel free to do so, I will be the last to force you to change your minds...
Ciao T
No cable exists that behaves like one. We can argue this endlessly.
I find your rectification story actually a lot more interesting than what you argue in this post.
I am interested in the real behaviour of imperfect items in an imperfect world. So comparisons to abstract ideals are meaningless to me, but comparisons between two imperfect item items to find which is more suited to the task is VERY meaningful to me personally.
No, all wires are defective by your definition, as non is an ideal shunt, in fact, an ideal shunt does no more exist than any other ideal anything, except perhaps in the mind of the divine, where the ideal shunt joins the ideal chicken coop, with ideal Chickens and no doubt ideal Chicken Excrement.
So we are back to select which wire defects we have least issues with. And surprisingly of course, we are back to basic electrics and any polemic about cheap or expensive, high end or low is meaningless in this context, as it has no relevance to the topic. So why insist on it?
Wires make a difference, deal with the facts.
If anyone does not like the facts, deal with them by going and stick the head in the sand, nobody forces anyone to take note or action, sticking the head in the sand has apparently been a good evolutionary strategy for the Ostrich for many years.
As I said, those who wish to remain wilfully blind, feel free to do so, I will be the last to force you to change your minds...
Ciao T
Surface oxidation occurs on most metals relatively quickly when exposed to air. In the case of cuprous oxide (which was used to make copper oxide rectifiers), it has a salmon color. The forward voltage drop of this type of rectifier is a few tenths of a volt with the uncorroded copper underneath acting as the cathode at currents up to hundreds of milliamperes. This forward voltage drop can be a few percent or less of the peak voltage differential of the signal between two ends of a given speaker cable.
With random and varying interstrand contacts along the length of an average multiconductor cable, and considering the load and frequency dependent voltage drops along its length, variations in conductivity between and along the lengths of individual strands, accumulating strand breakage at various points, particularly near each end as a cable is flexed or stressed, transmission line amplitude variations along the length of the cable depending on frequency, mostly for induced RF, it's not really surprising that interstrand rectification in copper cables has audible effects.
This may have been a reason that some considered stranded wire 'directional'. Perhaps they were actually listening to the interstrand rectification nonlinearities.
To make life even more interesting here, cuprous oxide also has a photoelectric effect with measurable voltages up to 250mV inducable by incident light. In this case, the uncorroded copper wire substrate is the anode. Something to consider when you're running that clear jacketed multistrand for a hopefully 'audiophile' system.
Then there are the other varieties of copper oxidation/corrosion with their varying electrical properties such as cupric oxide and the chlorides, sulfides and carbonates which give the lovely green patina that most such multistrand wires eventually acquire.
All speaker cables 'sound the same'....to the hearing impaired or one in willful denial, I'll admit.
With random and varying interstrand contacts along the length of an average multiconductor cable, and considering the load and frequency dependent voltage drops along its length, variations in conductivity between and along the lengths of individual strands, accumulating strand breakage at various points, particularly near each end as a cable is flexed or stressed, transmission line amplitude variations along the length of the cable depending on frequency, mostly for induced RF, it's not really surprising that interstrand rectification in copper cables has audible effects.
This may have been a reason that some considered stranded wire 'directional'. Perhaps they were actually listening to the interstrand rectification nonlinearities.
To make life even more interesting here, cuprous oxide also has a photoelectric effect with measurable voltages up to 250mV inducable by incident light. In this case, the uncorroded copper wire substrate is the anode. Something to consider when you're running that clear jacketed multistrand for a hopefully 'audiophile' system.
Then there are the other varieties of copper oxidation/corrosion with their varying electrical properties such as cupric oxide and the chlorides, sulfides and carbonates which give the lovely green patina that most such multistrand wires eventually acquire.
All speaker cables 'sound the same'....to the hearing impaired or one in willful denial, I'll admit.
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Yes, but that's in series. Very different physically than oxides which form between strands which are in parallel.
Yup, it does. Thing is, I've frequently stripped back insulation on wire that's twenty or thirty years old, and the copper underneath the undisturbed sheathing is clean and bright. So your effect may well occur, but only at the 10mm or so that's exposed at each end...
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