prk@charm.UUCP (Paul Kolodner) (05/09/85)
I recently posted a response to an article concerning "Hitachi super-pure cable". I got a few amusing responses, some privately. The most amusin all said: the following, in paraphrase: "How can you dump on gold-plated connectors? They don't oxidize!" My response (which I wouldn't bother making public if it weren't of obvious general interest, despite my ego involvement) is: yes, of course you want gold-plated connectors be- cause they don't oxidize like nickel! It's their resistivity which is irrelevant, which is what the salesman of my fable was too fable- minded to realize. Some other points which were raised: 1. Don't metel-to-wetal contacts form rectifiers, which are bad? Answer: what you're probably thinking about is thermoelectric voltages set up between different metals. Tht's dc and irrelevant. 2. Don`t metal-to-metal contacts oxidize, making a resistive barrier to what salesmen call "elecrtron transfer efficiency" in their quaint and amusing manner? Answer: an oxide layer in series with your speaker cable is a little capacitor. I could look in my E+M books to calculate its capacitance, but I'm too lazy, and the answer is obvious: the layer is very thin, the capacitance is very high, the resistive impedance of the circuit is very low, and the effect is very unimportant. 3. Don't oxidized metal-to-metal contacts form rectifiers, which are very, very bad for asystem which is supposed to be linear? Answer: I'm just not sure, but I really doubt it. Give me a reference, please.
herbie@watdcsu.UUCP (Herb Chong [DCS]) (05/09/85)
In article <661@charm.UUCP> prk@charm.UUCP (Paul Kolodner) writes: >I recently posted a response to an article concerning "Hitachi super-pure >cable". I got a few amusing responses, some privately. The most amusin >all said: the following, in paraphrase: "How can you dump on gold-plated >connectors? They don't oxidize!" My response (which I wouldn't bother >making public if it weren't of obvious general interest, despite my >ego involvement) is: yes, of course you want gold-plated connectors be- >cause they don't oxidize like nickel! It's their resistivity which >is irrelevant, which is what the salesman of my fable was too fable- >minded to realize. the reason the salesman gave was oversimplified, not totally off incorrect. >Some other points which were raised: >1. Don't metel-to-wetal contacts form rectifiers, which are bad? >Answer: what you're probably thinking about is thermoelectric voltages >set up between different metals. That's dc and irrelevant. true to a high degree, but some amps don't take kindly to even small DC offset voltages (mV or less). head-amps are most likely to suffer from this problem due to their low overloads. most amps have a sufficiently high CMRR though, to ignore this as a problem. also, many amps don't have DC input stages so that the DC is rejected. if there are problems with DC, it is usually manifested as a DC output from the amplifier stage. depending on the interstage coupling and the total gain in the system, this may or may not be a problem. almost always it is not because of high pass filtering between amplifier stages. >2. Don`t metal-to-metal contacts oxidize, making a resistive barrier >to what salesmen call "electron transfer efficiency" in their quaint >and amusing manner? Answer: an oxide layer in series with your speaker >cable is a little capacitor. I could look in my E+M books to calculate >its capacitance, but I'm too lazy, and the answer is obvious: the layer is >very thin, the capacitance is very high, the resistive impedance of >the circuit is very low, and the effect is very unimportant. you are forgetting something. the reason nickel is relatively oxidation proof is because it oxidises extremely rapidly, but the relative volume of the nickel oxide formed is so close to that of pure nickel metal that no bare metal is exposed due to craking of the oxide coat. (iron, for example take up much less volume than ferric oxide.) the nickel oxide seals the nickel off from oxygen in the air and so stops bulk oxidation as soon as it forms, which is very rapidly. scraping off the nickel oxide when inserting a plug will cause metal to metal contact (more or less) over a fairly wide area, but the metal will be just far enough apart in most cases to allow air in and nickel oxide to form. the contact surface becomes in two surfaces very close together with many points of actual metal-to-metal contact. the cross-sectional area of conductivity goes way down and resistance increases at the same time as capacitance increases. the magnitude of change depends upon the surface finish of the nickel plating. the result is a small capacitance in parallel with a resistance. this increases noise, if nothing else, in the input signal. in a high gain circuit, the noise can become objectionable. in high voltage sections, such as speaker cabling, the increases resistance can appreciably reduce the damping factor of the circuit to result in less control of the speaker system. the audibility of these is strongly dependent upon the component chain. >3. Don't oxidized metal-to-metal contacts form rectifiers, which are >very, very bad for a system which is supposed to be linear? Answer: >I'm just not sure, but I really doubt it. Give me a reference, please. they used to make rectifiers in the good ol' days with metal oxides. it is possible to form one but whether it is a good rectifier or not is impossible to say. the possibility exist though, and it is not negligible. whether it's audible depends on how good the rectifier is. you could try looking in these books for a more complete discussion. i have been told that the latter is the best in the field. Author: A. B. Glaser Author: G. E. Subak-Sharpe Title: Integrated Circuit Engineering Publisher: Addison-Wesley City: Reading, Mass. Year: May 1979 Author: A. Bar-Lev Title: Semiconductors and Electronic Devices Publisher: Prentice-Hall International Year: 1979 Herb Chong... I'm user-friendly -- I don't byte, I nybble.... UUCP: {decvax|utzoo|ihnp4|allegra|clyde}!watmath!water!watdcsu!herbie CSNET: herbie%watdcsu@waterloo.csnet ARPA: herbie%watdcsu%waterloo.csnet@csnet-relay.arpa NETNORTH, BITNET, EARN: herbie@watdcs, herbie@watdcsu
karn@petrus.UUCP (05/11/85)
I really wish every cop and traffic court judge was an audiophile of the "monster cable" persuasion. Then I could always get out of speeding tickets by arguing that radar readings are meaningless because of the relativistic time dilation that occurs when I'm driving. Phil
stv@qantel.UUCP (Steve Vance@ex2499) (05/22/85)
In article <1360@watdcsu.UUCP> herbie@watdcsu.UUCP (Herb Chong [DCS]) writes: >In article <661@charm.UUCP> prk@charm.UUCP (Paul Kolodner) writes: >>... >>ego involvement) is: yes, of course you want gold-plated connectors be- >>cause they don't oxidize like nickel! It's their resistivity which >>... >... >metal contact (more or less) over a fairly wide area, but the metal >will be just far enough apart in most cases to allow air in and nickel >oxide to form... To keep nickel, gold, or anything else from oxidizing, try a little WD-40. -- Steve Vance {dual,hplabs,intelca,nsc,proper}!qantel!stv dual!qantel!stv@berkeley Qantel Corporation, Hayward, CA
ron@brl-tgr.ARPA (Ron Natalie <ron>) (05/24/85)
> To keep nickel, gold, or anything else from oxidizing, try a little WD-40. > -- Or you could just encase them in plastic.
snoopy@utflis.UUCP (Snoopy) (05/25/85)
> In article <1360@watdcsu.UUCP> herbie@watdcsu.UUCP (Herb Chong [DCS]) writes: > >In article <661@charm.UUCP> prk@charm.UUCP (Paul Kolodner) writes: > >>... > >>ego involvement) is: yes, of course you want gold-plated connectors be- > >>cause they don't oxidize like nickel! It's their resistivity which > >>... > >... > >metal contact (more or less) over a fairly wide area, but the metal > >will be just far enough apart in most cases to allow air in and nickel > >oxide to form... > > To keep nickel, gold, or anything else from oxidizing, try a little WD-40. > -- > > Steve Vance > {dual,hplabs,intelca,nsc,proper}!qantel!stv > dual!qantel!stv@berkeley > Qantel Corporation, Hayward, CA I personally think WD-40 is super stuff. I was going to rustproof a car with it...it is the ideal stuff for bicylcle chains as is all petroleum distillate stuff...but....the military does not used this stuff as it is known to cause oxidateion (ie rust ). D'ont know where I read this , but it was dissapointing info. ray