By the way, if anyone has a meter that can measure down to 80 milliohms (.08 ohms), let me know. I’ve owned many different ohmmeters including the best of both analog and digital, and none can measure below 0.1 ohms, more usually 0.2 ohms, and that’s with the two leads touching.
Some thoughts about tonearm wire
Recently, I purchased a used AT-1100 tonearm with two arm tubes. It has the original factory silver wire, a nice touch I thought. When I open the arm up to clean the bearings and re-oil them, I discovered the tonearm wire is so thin that it is not much thicker than the thin hair on my balding head! I am talking about the OD of the insulation, the wire itself is much thinner! The other tonearms I opened up to clean and re-oil, the copper wire was so much thicker.
I am not making a comment here about whether silver or copper is better. But no one seems to consider the wire gauge of the wire in question when discussing sound quality vs. wire material. Regardless of how one material might sound over another, if the resistance, capacitance, and inductance is the same, the comparison has merit. This silver wire is so thin, I can't help to think any sound improvement (or loss, depending on your viewpoint) is swamped by the gauge differences.
Sure, silver is a better conductor than copper, but only when the gauge is the same. Once the silver wire gauge gets smaller, copper starts having an advantage in resistance, while silver starts having an advantage in reduced capacitance and disadvantage in higher inductance when compared to copper of a given gauge.
I can't help thinking gauge is one thing that differentiates sound quality of silver vs. copper in tonearm wiring, as well as cabling to the preamp. Those MC signals are tiny, and MM or MI is not a lot better. MC sees a very low impedance, so inductance and resistance becomes more of a factor than capacitance. MI and MM sees a much higher impedance, so capacitance becomes more dominant than inductance or resistance.
Thoughts or comments?
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@lewm There is no way that tonearm wire is as thick as 33g! One can see the insulation, but one cannot see the wire inside it when looking at the end cut. I have a wire stripper that can strip down to 32g, but that insulated wire slips right through it. As for wire gauge affecting only resistance, that is not true. The math for calculating inductance is complex, but you can find inductance calculators online to determine the inductance of a wire. The bandwidth numbers I posted above are just from that calculation. Also note that wire has a surface area just like capacitors. Put them closer together, the capacitance goes up. Make the surface area larger and the capacitance goes up. Move them apart, capacitance goes down and inductance goes up. The fact is, resistance, inductance, and capacitance are linked together. Changing one will alter the others. I do have a milliohm meter in the lab, and it uses a 4 terminal Kelvin measurement. It can easily measure 0.001 and 0.0001 Ohms. The catch is it pumps 10 Amps down the test subject, and it measures the voltage drop to display milliohms. If I pumped 10 Amps down that tiny wire, I am sure it would smoke it! Frankly, I would be squeamish about sending a 1mA as a test current. The only way I could measure the resistance in that tonearm is to determine the lead resistance and subtract that from the reading. Indeed, a process fraught with errors. The best approach would be to just replace the wire with a known & larger gauge I can't do this in the lab, and the quotes from folks who can do this is more than I want to spend on the project. |
I did not say a length of wire does not have inductance (or capacitance). I did say that the gauge of the wire has little effect on reactance (thinking of a single conductor in space with nothing around it), compared to the geometry of the wire in relation to other conductors that might be carrying either ground return or the opposite phase of a balanced connection, in an IC or inside a tonearm wand, where you have two hots and two grounds running close together in the case of an SE circuit or two positive and two negative phases, if the cartridge is running balanced mode. Twisting increases C, and running them side by side might increase L. Also, the wires inside a chassis can affect each other’s reactance depending upon how they are routed with respect to one another. The effect of those factors on capacitance would outweigh the difference in capacitance between two very thin wires of slightly different gauge singly in free space, or at least I think so. If you have some data, I would be interested to investigate this further. Most of us by and large do not have access to your lab equipment. Therefore, when you say that resistance should be less than 80 milliohms (I think that is an accurate paraphrase, but if not, please correct me), that is not a useful criterion for the rest of us who cannot measure down past, really 0.2 ohms. I have expensive Fluke digital and Triplett analog meters, and neither can go that low. My Fluke meter reads 0.2 ohms when the two leads are in contact. Furthermore, the slightest bit of dirt, grease, or whatever on the probe would screw up the reading of 80 mohms. I also did not mention it before, but why or how did you settle on 80mohms as the max permissible resistance? Just wondering. I have thought on this issue myself, once in a while. Many gain stages use a resistance in series with the grid of the gain tube or the gate of a transistor, in order to suppress oscillation of the circuit. In a tube stage, the value of such a resistor is usually at least 100 ohms. I wonder how the resistance of the wire carrying the signal to one end of the "grid stop" resistor could make much difference in light of that fact. I am agnostic, unsure what to think about that. Forgot to mention that if you think your tonearm wire is thinner than 33G, based on direct inspection, I stand corrected. Must have been a bear to solder that stuff. |
@jc4659 I have experienced works undertaken on the Mechanical Interfaces and as time went on diverted the focus onto the electrical side of the same TA. After a selection of designs and wire types tried. A certain wire used continuous really shone through for the attraction brought with it. It also left the impression the work undertaken on the mechanical interfaces were now really able to show off the quality they had created. I fully understand your reaction to your own experience. Femo's of such designs wins advocates fast. |
@lewm Actually, the 0.080 Ohms is not my criterion, it was posted earlier in this thread by westcoastaudiophile. I don't know how s/he came up with that or if it was published somewhere. Either way, if a tonearm wire resistance is that low, it would be hard to beat for a MC setup. Given there are multiple contacts in the chain and round trip to the preamp and back, I suspect it is more than 80 milliohms. When I get the tonearm back from service, I will try to measure the resistance of that tiny wire. I suspect, but have no way to prove it, that one continuous length of wire with no contacts, just soldered connections from cartridge pins to preamp input, the sound quality will be dominated by this rather than the type of wire in the conductor. "Twisting increases C, and running them side by side might increase L" Actually, twisting decreases L, not increases it. The reason is the same for side by side wiring, current in one direction induces a current in the adjacent conductor in the opposite direction. But since this is the direction the current is flowing in the adjacent conductor, inductance decreases. As the wires move apart, inductance then increases while capacitance decreases. In this case, resistance remains constant. Increasing the gauge of the wire changes everything, but the basic rules remain the same.
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