Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site mordor.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!ihnp4!zehntel!dual!mordor!sjc From: sjc@mordor.UUCP (Steve Correll) Newsgroups: net.audio Subject: Re: Why do cables make a difference? Message-ID: <5317@mordor.UUCP> Date: Tue, 14-Aug-84 05:14:27 EDT Article-I.D.: mordor.5317 Posted: Tue Aug 14 05:14:27 1984 Date-Received: Thu, 16-Aug-84 01:30:41 EDT Organization: S-1 Project, LLNL Lines: 48 I honestly do not know why cables are reported to affect the sound of audio systems, but I will offer some hypotheses which one might test: 1. Many phonograph cartridges are quite sensitive to load capacitance. I have seen graphs in Audio magazine suggesting that cables and preamp inputs vary enough in capacitance to affect the high-frequency response of a cartridge by several dB, whereas people seem able to discern variations of less than 1 dB. Since the optimum value of capacitance varies with the cartridge in question, simply minimizing capacitance may make some perform better and others perform worse. If high-end audio manufacturers were really interested in improving turntables, they would stop touting pads, platters, and bases made out of esoteric substances, and they would start putting a few FETs inside the cartridge itself to isolate its coils from the load of the cables and preamp. With current technology, the circuitry would increase the mass of the cartridge/arm combination very little. (In fact, the tiny additional wire required to bring a few milliamps from a power supply in the base of the turntable up through the arm to the cartridge would probably weigh more!) 2. A few preamps are overly sensitive to load capacitance. Studios insist that line outputs be able to drive low-impedance but reactive loads without straining, and the IHF/EIA specs define a reactive load to be used in testing preamps. But one trend in high-end audio is to minimize both the amount of active circuitry and the amount of feedback used in amplifiers, and the tradeoff for this is often to make the whole system more sensitive to loading. 3. Contact corrosion can subtantially affect audio signals whose amplitude is less than a few dozen millivolts during quiet music. 4. A cable which admits RFI might cause active circuitry to saturate or slew even though the interference frequencies are too high to hear. 5. Double-blind tests are fairly rare in this field. While I like to consider myself objective, if I were at a wine-tasting party and I liked a Gallo wine better than a Chateau St. Jean, I certainly wouldn't admit it. If you hid the labels, however, there's no telling what embarrassing judgements you might elicit from me. --Steve Correll sjc@s1-c.ARPA, ...!decvax!decwrl!mordor!sjc, or ...!ucbvax!dual!mordor!sjc -- --Steve Correll sjc@s1-c.ARPA, ...!decvax!decwrl!mordor!sjc, or ...!ucbvax!dual!mordor!sjc