Hi,
That is why my cables are goldplated silver. There are a number of suppliers of scientific use wires in the UK, who can supply goldplated silver of very high grades.
Another issue is that for single-ended cables a symmetric arrangements of conductors for signal and return is seriously subideal.
This is now straying into stuff I do commercially, so I cannot say much more, but just consider that the ground connection combines signal and parasitic currents from the mains often of several mA or more.
I normally like to use the thinnest wire I can get away with (see also Malcolm Hawkesford on the subject), but thin wire ground connections are trouble.
Over time I have tried a lot and have arrived at something that works very well, if one thinks about all the factors the kind of design I arrived at is quite obvious.
Ciao T
That is why my cables are goldplated silver. There are a number of suppliers of scientific use wires in the UK, who can supply goldplated silver of very high grades.
Another issue is that for single-ended cables a symmetric arrangements of conductors for signal and return is seriously subideal.
This is now straying into stuff I do commercially, so I cannot say much more, but just consider that the ground connection combines signal and parasitic currents from the mains often of several mA or more.
I normally like to use the thinnest wire I can get away with (see also Malcolm Hawkesford on the subject), but thin wire ground connections are trouble.
Over time I have tried a lot and have arrived at something that works very well, if one thinks about all the factors the kind of design I arrived at is quite obvious.
Ciao T
Sebastian, care to share your schematic including the DC-servo's? Im interested in this design and in need of a summer project
Don't worry. As soon it is all finalized and finished I am more then willing to share. I learn and got so much information from this forum, that I love to give my contribution. However, Before people going to build something I designed, I want to make sure it is reliable, finished and tweaked to a truth adult product. So please be patient, It is still in further development for some final tweaks. I show up here soon when it is finished. I will make PCB's available as well.
With kind regards,
Bas
I like the way you put it!
One problem I have though, is that silver is not very stable when not sealed... And natural insulation materials are almost always loose in some way,
Agreed. That's also one of the reasons I kept this config with the tape. The packing tape is by itself quite thin. It actually only touches the silver on a small line on top and bottom. The two pieces of tape seal on either side of the silver wire so the wire is actually surrounded by air sealed in an air tight envelop. After 18 months, there is no tarnishing of the silver, so no degradation in the conductor.
I hard wired the interconnect from the DAC to the chipamp to eliminate the negative impact of RCA plugs.
You could try Toback as a supplier. It is just a small package in the post. I live in Canada and tried everywhere for a competitive price, and even with the shipping, nothing came close to their value.
I think as Thornston suggests, gold plated silver would work in cotton.
I've read Mr Hawkesford's paper and found it most interesting. (I actually find a scientific dissertation on the properties of cables interesting... jeez, that's beyond geeky)
It became quite clear that both the conductor and the dielectric should be as homogeneous as possible (so no plated wires then).
Also, the purity of conductors has been suggested to be significant factor (so only OCC 5N or better silver).
I'm entertaining the idea of enamelling the wires (to seal silver off from air), and then simply glueing them onto a paper ribbon. This should be relatively simple, and might work reasonably well... But of course, this would do nothing to minimise vibrations, so perhaps some sort of outer sheath would be a good idea.
One thing bugs me though: why Silversmith Audio - manufacturer hailed by many as the best in the world, and who openly admit that they rely on Hawkesford's works - use thin ribbon conductors, not round?...
It became quite clear that both the conductor and the dielectric should be as homogeneous as possible (so no plated wires then).
Also, the purity of conductors has been suggested to be significant factor (so only OCC 5N or better silver).
I'm entertaining the idea of enamelling the wires (to seal silver off from air), and then simply glueing them onto a paper ribbon. This should be relatively simple, and might work reasonably well... But of course, this would do nothing to minimise vibrations, so perhaps some sort of outer sheath would be a good idea.
One thing bugs me though: why Silversmith Audio - manufacturer hailed by many as the best in the world, and who openly admit that they rely on Hawkesford's works - use thin ribbon conductors, not round?...
Instead of enamel, why not use a very thin layer or two of clear laquer? That's what is usually used on decorative copper and silver items, to keep them from oxidizing. There's one very important trick, for that, though: If you do it at too low a temperature (e.g. room temp), it will later "leak", through zillions of tiny cracks that form (that are too small to see with the naked eye), and tarnish (oxidation) will form. [On decorative items, that can be a pain because the oxygen can get in but the tarnish remover generally can't. At that point, it needs laquer remover, then tarnish remover, and then new laquer.] So, warm the metal in the sun, or in a very-low-heat oven, to at least the highest temperature the metal is likely to see again, before applying the laquer. And since your wire will be relatively low mass, compared to the laquer, I guess the laquer should also be warmed (be careful, since it's flammable!).
However, I should point out that in the RF lab world, where there really is a skin effect, and our connectors and adapters cost several hundred dollars each, it has been shown that silver tarnish is not nearly as significant a problem as one might think. But the laquer would give you some insulation, too, and you would still be able to see the shiny silver.
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The reason they use a foil rather than a wire is revealed in Allen Wright's book on cable building. The idea is that certain frequencies travel closer to the outside of the wire and some on top while lower frequencies travel in the middle. If they travel in the middle they kind of draaaaag through the wire. Imagine one single pulse in the shape of a disc traveling through the wire. At the middle of the wire it would drag a bit behind itself creating a cone shape. The idea is that bass frequencies do this and the way to get them closer to the surface where they dont drag as much is to use thinner and thinner wire but then we run into other troubles so if we go to a foil it has the advantage of thin without the disadvantage thin. More surface area allows more current and has less resistance.
Uriah
Uriah
Well, it's actually kind of the opposite. Skin effect creates a problem for higher frequencies. And there is no changing of the speed that different frequencies travel through a conductor, due to skin effect. What changes is the resistance for different frequencies. But for lower frequencies, there is actually less resistance than for higher frequencies. Traveling also in the middle of the conductor is a good thing, since more of the conductor can be used, which lowers the resistance. Higher frequencies tend to go more toward the outside (the skin), and don't get to use as much of the conductor, so they tend to see a higher resistance.
But, for even the highest audio frequencies, there is almost never a problem with skin effect, since the skin depth would be greater than the radius of the wire, for all commonly-used conductor metals and wire sizes, at those frequencies. However, with a relatively large wire size, such as 12 AWG, the ratio of the AC and DC resistances could get up to about 1.035 at 20 kHz, in the worst-case (i.e. solid wire, as opposed to stranded, which would be better).
If you are actually worried about skin effect at audio frequencies, try Litz wire, which has the strands braided together in a certain way so that the overall magnetic field acts equally on all the wires and causes the total current to be distributed equally among them, which in-effect increases the skin depth. Litz wire also mitigates the proximity effect.
See Skin effect - Wikipedia, the free encyclopedia and Skin Effect Relevance in Speaker Cables — Reviews and News from Audioholics .
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Hi,
Could work quite well.
Cables and science is a difficult subject.
I suspect Silversmith tried different approaches and found ribbons work better. A ribbon can of course have a much larger surface or crossection for a given thickness, which helps with the keeping the ground connection low impedance.
I personally still stand by my old articles in TNT-Audio.
The most impact in cables is had from the actual geometry (that is shape and size of conductors, spacing, other arrangements) and the electrical properties dictated thereby.
Microphonics can become significant as levels get lower.
Dielectric quality can become significant as the impedances in the circuit rise.
So, for universal cables we should address the above items reliably and these items can all be demonstrated by measurements to produce sufficient differences to be audible.
Items such as stranded vs. solid core conductors, metal quality and material itself (silver vs. copper etc.) have proven difficult to illustrate by measurements.
A final item are connectors. Most are of a design and quality that they quite reliably remove any possible positive quality of the cable they are attached to.
Ciao T
Could work quite well.
Cables and science is a difficult subject.
I suspect Silversmith tried different approaches and found ribbons work better. A ribbon can of course have a much larger surface or crossection for a given thickness, which helps with the keeping the ground connection low impedance.
I personally still stand by my old articles in TNT-Audio.
The most impact in cables is had from the actual geometry (that is shape and size of conductors, spacing, other arrangements) and the electrical properties dictated thereby.
Microphonics can become significant as levels get lower.
Dielectric quality can become significant as the impedances in the circuit rise.
So, for universal cables we should address the above items reliably and these items can all be demonstrated by measurements to produce sufficient differences to be audible.
Items such as stranded vs. solid core conductors, metal quality and material itself (silver vs. copper etc.) have proven difficult to illustrate by measurements.
A final item are connectors. Most are of a design and quality that they quite reliably remove any possible positive quality of the cable they are attached to.
Ciao T
After much reading and experimenting, I too came to the conclusion that a flat ribbon with equal spacing of conductors is best. Minimal dielectric is also key. I was going to use solid 5-9s silver sewn into cotton for the best dielectric solution. As a proof of concept I built some using clear packing tape. The result was so good, I never moved on to cotton.
I buy pure silver wire at Myron Toback mail order from NYC. It's a jewelry supply house that sells by the ounce. an once of pure silver is $20, and at 28 gauge that is ALOT of wire... Page 51 - Myron Toback 2009 Catalog
Based on research by Jade on audio asylem, I went nuts and added one strand of pure gold on the + conductor + 2 strands of silver all at 28 gauge. The neg has 1 strand of 24 gauge silver. JadeD claims pure gold is the best. At $10 a foot, gold gets expensive, and I'm not sure its that much better.
At any rate, the interconnect is amazing. I also built speaker cables the same way with a lot more conductor and I think they are pretty decent too.
See Copper wire .
Silver is clearly the number one conductor, and copper is number two.
Silver is 41% better at conducting electricity than gold (and 5.8% better than copper). Copper is 33.49% better than gold. But at least the surface of gold doesn't oxidize (tarnish) very much. However, the surfaces of silver and copper can easily be sealed from contact with air, to prevent oxidation (except in the contacts of connectors, which is why they are usually plated with something else, there, or an alloy is used).
One other potential problem with gold is that when it is in contact with certain other metals, "bad things can happen", which, in electronics, often ends up causing bad connections (i.e. with high resistance). It is safest to only mate connectors or make solder joints with two metals that are identical or are known to be compatible. Soldering gold-plated pins to copper circuit boards, for example, has caused a lot of problems in the past. If I recall correctly, the gold and the tin in the solder "didn't like each other", and over time formed high-resistance alloys. In another example, there was a recall, a few years ago, of computers that contained memory modules with standard tin-plated connectors that were plugged into gold-plated sockets, which over time tended to form a high-resistance film at the point of contact.
Often we are also influenced by the fact we know which topology get used. Years ago when I wasn't into designing myself but a reviewer for a hifi magazin an a pure listener, I was totally blown away by a certain Linn Amplifier. Years later I found out that this amplifier is based on TDA chips. I am sure if I knew that by that time, I never liked it as much anymore as I did
Hi Bas,
I agree with you. When we see, we make bias. Better know nothing, but listening.
Panson
That's interesting. I checked all the equations in Hawkesford's paper (took me some time - haven't done proper physics in a while...), and the theory behind his reasoning seems sound. He did make a few simplifications, and his practical experiments were lacking somewhat, but the main model is certainly not flawed.
So what did jneutron write in his "debunking"?
This is exactly what I meant - a clear coat of some laquer. Thanks for the wire heating tip!
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That is fascinating! I did not realize this. In the early days of mainframe computers, all the conductors were pure gold, so I just assumed it was the best. It likely was used for the lack of corrosion.
The advocates of gold in ICs seem to point to it adding a warmth. I do think I could image there is some level of warmth without distortion in the cable with gold vs pure silver. Given how dirt cheap the silver is, and how good it is in the right architecture, it would be my #1 conductor of choice.
My thoughts
Are you sure about that? In my day I designed many computers, and I still do. We generally used a gold plated base metal for conductivity. Gold is great for this as it has excellent conductivity and is non-corrosive. However gold is too expensive in bulk and it doesn't have the springy attribute required for connectors so gold plating was normally used on a base metal such as copper-beryllium. Now with rohs there are new mixtures but I never saw pure gold used anywhere except in things like super sensitive calorimetric circuits.
I still remember when we used blood plasma for cooling...
Are you sure about that? In my day I designed many computers, and I still do. We generally used a gold plated base metal for conductivity. Gold is great for this as it has excellent conductivity and is non-corrosive. However gold is too expensive in bulk and it doesn't have the springy attribute required for connectors so gold plating was normally used on a base metal such as copper-beryllium. Now with rohs there are new mixtures but I never saw pure gold used anywhere except in things like super sensitive calorimetric circuits.
I still remember when we used blood plasma for cooling...
Hard to say... I was too young to be sure. I am referring to IBM mainframes circa late 70's. 370/155, 158, 168 etc. About $10m ea. When they served their useful life they were sold for scrap to recover the gold, or so they said at the time.
Another update on my quest for the holy grail of audio amplification - I made a significant step forward, where I didn't expect it!
I replaced the old transformer in my amp - Nuvotem Talema (which is a decent transformer make, and is often recommended) 225VA, 2x18V, fully encapsulated - with a new, custom-made unit:
400VA, 2x22V, GOS (Grain Ordered Steel) core, electromagnetic shielding, shielding between windings, secondary winding made with 50% thicker wire, primary windings wound over secondary;
Its workmanship quality seems second to none, and the transformer is dead quiet.
What I expected was some improvement in bass (due to higher wattage), perhaps slightly better dynamics due to higher voltage, and I was hoping for "some" general, nonspecific improvement.
What I got was a FUNDAMENTAL quality improvement in virtually all areas. Bass indeed improved - it became more powerful, in this effortless kind of way; the improvement in trebles was if anything even more pronounced - they became so rich, brilliant and crystalline. Midrange is now very clean, vocals are so much easier to understand, there's more "air" around instruments. Improvement in detail retrieval is massive and easily as significant as when changing Panasonic FC capacitors to Black Gate N (possibly more). The whole soundstage actually shifted, everything sounds different now: it's holographic, transparent.
One side effect of this massive improvement in detail and transparency is that I seem to "hear" more inadequacies of the system, both up and down the stream...
I got the "recipe" for this transformer from Peter Daniel (although his suggestion was to use 300VA rating, and amorphous core). But because I couldn't find amorphous anywhere, I decided to give GOS cores a go - according to the manufacturer, it's even better (has higher induction in the core), and allows for wattages higher than 300VA. Whether it sounds better than amorphous - I do not know - but I can confirm that it sounds light years better than a "normal", good quality toroid, and I heartily recommend it to anyone serious about their amplifier.
Best part is - it was actually quite cheap, it cost me only about 50GBP from toroidy.pl - although that does not include shipping to England, because I collected it myself while I was on holiday in Poland. The shipping would have been quite expensive due to the weight of the transformer - another 20GBP or so for courier delivery.
But if you think about it - 50GBP would only buy you a standard transformer of comparable spec from RS-Components - so even with the shipping charge I suppose ordering from Poland is still a good deal, considering how much better it is than standard.
Of course, for many locations in the world ordering from Poland is not really an option - in this case you can try to find a reputable local manufacturer and ask them to make you a transformer of the above spec. It is well worth it.
- I made a significant step forward, where I didn't expect it!I replaced the old transformer in my amp - Nuvotem Talema (which is a decent transformer make, and is often recommended) 225VA, 2x18V, fully encapsulated - with a new, custom-made unit:
400VA, 2x22V, GOS (Grain Ordered Steel) core, electromagnetic shielding, shielding between windings, secondary winding made with 50% thicker wire, primary windings wound over secondary;
Its workmanship quality seems second to none, and the transformer is dead quiet.
What I expected was some improvement in bass (due to higher wattage), perhaps slightly better dynamics due to higher voltage, and I was hoping for "some" general, nonspecific improvement.
What I got was a FUNDAMENTAL quality improvement in virtually all areas. Bass indeed improved - it became more powerful, in this effortless kind of way; the improvement in trebles was if anything even more pronounced - they became so rich, brilliant and crystalline. Midrange is now very clean, vocals are so much easier to understand, there's more "air" around instruments. Improvement in detail retrieval is massive and easily as significant as when changing Panasonic FC capacitors to Black Gate N (possibly more). The whole soundstage actually shifted, everything sounds different now: it's holographic, transparent.
One side effect of this massive improvement in detail and transparency is that I seem to "hear" more inadequacies of the system, both up and down the stream...
I got the "recipe" for this transformer from Peter Daniel (although his suggestion was to use 300VA rating, and amorphous core). But because I couldn't find amorphous anywhere, I decided to give GOS cores a go - according to the manufacturer, it's even better (has higher induction in the core), and allows for wattages higher than 300VA. Whether it sounds better than amorphous - I do not know - but I can confirm that it sounds light years better than a "normal", good quality toroid, and I heartily recommend it to anyone serious about their amplifier.
Best part is - it was actually quite cheap, it cost me only about 50GBP from toroidy.pl - although that does not include shipping to England, because I collected it myself while I was on holiday in Poland. The shipping would have been quite expensive due to the weight of the transformer - another 20GBP or so for courier delivery.
But if you think about it - 50GBP would only buy you a standard transformer of comparable spec from RS-Components - so even with the shipping charge I suppose ordering from Poland is still a good deal, considering how much better it is than standard.
Of course, for many locations in the world ordering from Poland is not really an option - in this case you can try to find a reputable local manufacturer and ask them to make you a transformer of the above spec. It is well worth it.
Uncle,
thank you.
Now for the details:
input voltage? extra tappings?
output voltage at nominal input 230:22+22Vac?
regulation?
size, weight?
primary wire thickness/area?
secondary thickness/area?
Clarify:
electromagnetic shielding. Gos band around the outside perimeter?
shielding between windings. Electrostatic screen between Primary and secondary and connected to chassis?
thank you.
Now for the details:
input voltage? extra tappings?
output voltage at nominal input 230:22+22Vac?
regulation?
size, weight?
primary wire thickness/area?
secondary thickness/area?
Clarify:
electromagnetic shielding. Gos band around the outside perimeter?
shielding between windings. Electrostatic screen between Primary and secondary and connected to chassis?
Andrew,
You are right, I wasn't being entirely precise!
Here is more details:
Primary:1x230V
Secondary: 2x22V
Regulation: I did not specify that while making order, I assume 5%
Size/Weight: I considered them largely irrelevant, and I told the manufacturer to go with what they deem best; I can measure it when I get back home if you'd like me to.
Primary/Secondary thickness: I'm not entirely sure, as I wasn't given this information; but Secondary is VERY, very thick indeed. I had to trim the leads quite considerably before they would fit in the PSU board
Electromagnetic shielding: It looks like metallised foil wrapped around the outside circumference of the transformer.
Shielding between windings: It is an electrostatic screen between Primary and Secondary, connected to earth.
Sorry I can't be more informative, I will post some pictures when I get back home, they may tell you a bit more. I suppose I could also contact the manufacturer and ask them for more details, as I'm not an expert in this field anyway...
You are right, I wasn't being entirely precise!
Here is more details:
Primary:1x230V
Secondary: 2x22V
Regulation: I did not specify that while making order, I assume 5%
Size/Weight: I considered them largely irrelevant, and I told the manufacturer to go with what they deem best; I can measure it when I get back home if you'd like me to.
Primary/Secondary thickness: I'm not entirely sure, as I wasn't given this information; but Secondary is VERY, very thick indeed. I had to trim the leads quite considerably before they would fit in the PSU board
Electromagnetic shielding: It looks like metallised foil wrapped around the outside circumference of the transformer.
Shielding between windings: It is an electrostatic screen between Primary and Secondary, connected to earth.
Sorry I can't be more informative, I will post some pictures when I get back home, they may tell you a bit more. I suppose I could also contact the manufacturer and ask them for more details, as I'm not an expert in this field anyway...
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