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Subject: FAQ: rec.audio.* Misc 7/07 (part 13 of 13)

This article was archived around: 15 Jan 2009 06:01:57 GMT

All FAQs in Directory: AudioFAQ
All FAQs posted in: rec.audio.tech, rec.audio.opinion, rec.audio.misc, rec.audio.marketplace
Source: Usenet Version


Archive-name: AudioFAQ/part13 Last-modified: 2007/07/12 Version: 2.17
20.0 Miscellaneous 20.1 What do I need to know about warranties? Warranties have a few basic components. The first is the term of the warranty. The second is what is covered. The third is who supports the warranty. The fourth is what restrictions. Term is fairly self evident. What is covered is more detailed. In audio electronics, typically everything is covered with a "parts and labor" warranty. Often mechanical components such as tape heads are covered by different terms, such as shorter terms on labor and longer terms on parts. Likewise, speaker warranties vary widely, from unconditional with no term limit to a basic 30 days parts and labor. Some warranties come from the manufacturer. Others come from the dealer. Still other warranty support is available with certain premium charge cards. A common restriction on some warranties is that the equipment is not covered unless it is sold by an authorized dealer. A few dealers have lied about being authorized dealers. Equipment sold by an unauthorized dealer is almost always sold completely legally. This unauthorized dealer may, in fact, be fully authorized to sell, but not authorized to sell manufacturer's warranties. In buying gear this way, dealers can get it cheaper, and provide the service themselves. This kind of gear, with a full warranty from the dealer is referred to as gray market equipment. Manufacturers discourage buying from these gray market dealers, but the risks are fairly low. If the dealer is local and well established, the risks are minimal. If you buy equipment mail-order, a dealer warranty may be a pain in the neck, especially if you have to ship the gear to the dealer more than once to get it fixed correctly. Then again, some factory service requires shipping gear far away at your expense, too. Frequently, home audio equipment is sold with a warranty restriction that if the gear is used commercially or in any profit-making enterprise, then the warranty is void. This is to protect the manufacturer from having to frequently repair equipment meant for light service. Professional audio equipment often comes with very liberal warranty terms, such as lifetime parts and labor. Professional gear takes heavy use and severe wear from constant transportation. It is expected to be able to take this abuse. All gear, electronic and mechanical, is known to have three principal failure modes: abuse, infant failure, and end-of-life failure. In addition, a few of the failures occur at random. Infant failure (also called juvenile failure) occurs in the first fifty hours of use, and is the principal responsibility of warranties. Infant failure is frequently caused by defective parts or a design defect. Abuse failure is that caused by a person who pulls a cable too hard, bangs the equipment on the table, pushes the controls too firmly or too fast, or does anything else which the manufacturer did not expect. These are the gray areas of warranties. They do not represent a manufacturing defect in the manufacturer's eyes, but they do leave you with a broken device. To get the best chance of coverage against this kind of failure, select a brand or a dealer with a very liberal warranty policy. End-of-life failures are rarely covered by warranty. Tape heads have a finite, calculable life, as do rubber rollers, speakers, cables, batteries, bearings, and motors. The life of some of these components can be extended by intelligent care. For example, the life of common rechargeable batteries can be extended by good recharging practice. Likewise, some cleaners can dry out rubber, and will lead to premature failure. Don't expect warranty support for any of these problems, and if you get it, feel lucky. 20.2 What is blind testing? Non-blind? Double-blind? If you want to compare pieces of equipment, recordings, or people, you could run an experiment. You could select an experimenter to initiate various trials, select some subjects to listen to the sounds, and then ask the subjects questions about what they hear. However, if you want meaningful results, it is necessary to set up the experiment correctly, and ask the right questions. One of the major problems with any experiment is that the subjects may become aware of the experimenter's hypothesis and allow this awareness to influence their behavior. One technique for preventing such bias is to keep the person who conducts the experiment unaware of the hypothesis of the research. Unfortunately, experimenters invariably form SOME hypothesis of what's going on, and these hypotheses affect how they deal with subjects. A more reasonable solution involves allowing the experimenters to know the true hypothesis but somehow keeping them ignorant of the specific experimental condition of each subject. This is known as a Partial Blind Experimenter technique. An example of this is that the person running an experiment knows that the main experimenter wants to determine which connecting cables are best at signal carrying, but would not know which cables are being used at any given time during the experiment. It is also important for subjects not to become aware of the experimenter's specific hypothesis. Subjects often become highly responsive to any cues, intended or unintended, in the research situation that suggest what they are supposed to do to appear normal or "to make the study come out right." This problem can be present in judgment experiments, particularly those in which each subject is exposed to more than one variation of the stimulus. Such a procedure, by its very nature, increases the probability that the subject will begin to guess which aspects of the experiment are being systematically varied by the experimenter. Many studies avoid this problem with what is called a Blind Subject technique. Using this approach, subjects are not told specifically what the hypotheses are. Additionally, subjects are not told what specific experimental conditions they are in. For example, a subject might be told that he/she is supposed to determine which stereo system sounds better, when in fact the experimenter wishes to examine which color or appearance of the same components looks better to subjects. When both a Partial Blind Experimenter technique and a Blind Subject technique are used at the same time, this is called a Double Blind experiment. Double Blind experiments have higher probability of producing statistically valid results than Partial Blind Experimenter alone, Blind Subject alone, or other techniques. Double Blind experiments are highly recommended. 20.3 Where can I get a service manual or parts for brand XXX? The most reliable source of supply is the manufacturer's sales office in your country. Here is a list of company contacts that may be helpful in the US. (Please send additions & corrections etc. to neidorff@ti.com. AOC 800-775-1262 Akai Service Center 818-794-8196 AR (now part of NHT; see NHT) (AB Tech Services 800-225-9847 Ex AR Employee; Repairs old AR products) Cannon 516-933-6300 Casio 201-361-5400 Daewoo 800-782-4922 Emerson Radio 800-388-8333 Sanyo/Fisher 213-605-6756 General Electric 800-447-1700 Goldstar 800-222-6457 Hitachi 800-526-6241 JVC 800-252-5722 Kenwood 213-639-9000 Philips/Mag/Sylvania 615-475-8869 Mitsubishi/Akai 714-220-1464 NEC 201-882-9008 NHT 707-747-3331 NHT 800-969-2748 NHT 800-648-9993 Nutone 800-543-8687 Onkyo 201-825-7950 Panasonic/Quasar 215-741-0676 RCA 317-231-4151 Samsung 800-542-1302 Sanyo 800-421-5013 Sharp 800-526-0264 Sony 800-282-2848 Soundesign 800-888-4491 Teac 213-726-0303 Teknica 800-962-1271 Toshiba 201-628-8000 Vandersteen 209-582-0324 Zenith 312-745-5152 Alternately, contact one of the repair parts dealers listed in section 10.15 above. MCM and Parts Express offer free catalogs which can be very helpful for locating parts. 20.4 Where can I get good repairs on brand XXX? 20.5 How can I take 115V gear over to a 230V country or vice versa? Some equipment is available with an international power supply, which can be rewired by any serviceman to either power line voltage. If you expect to be moving abroad, look for this kind of equipment. Often, the same model is available both as US only and as International. Some equipment will be rewirable and won't say it. Adcom amps are known to be rewirable. If you rewire equipment from one voltage to another, be sure to also change the fuse(s). The correct value is often printed on the case or chassis of the equipment. If an amplifier, for example, is rewired from 115V to 230V, the fuse current rating needs to be reduced by 50%. If you know that your gear is limited to one power line voltage, you can order a new power transformer for that receiver, CD player, amplifier, or tuner which will be wound differently. Contact the manufacturer's local service center. This can be very expensive. A new transformer for a 40 watt receiver would wholesale for under $25 but cost $75 from a service center. Another alternative is to buy a power transformer that will convert 115V to 230V and vice versa. This is only practical for smaller gear. Larger power amps require prohibitively massive and expensive transformers. Also, the addition of a transformer may hurt the sound quality. Here are some common transformer models and 1992 list prices. Power ratings are total line current multiplied by line voltage (2A at 115V is 230 watts). Larger transformers cost more. Some of the costlier transformers are constructed with plugs and jacks for immediate use. Those marked * have wire leads and need safe connections to be used. Before spending money, check into other things about audio in the new country. Broadcast frequencies are slightly different in some countries than in others, so a receiver or tuner bought in one country may not be able to receive some or all of the stations in another country. The US separates the AM broadcast band frequencies by 10kHz while the UK uses 9kHz. Similarly, the US separates FM stations by 200kHz, where the UK has stations on a 50kHz spacing pattern. It MAY be very simple to modify a receiver from US to UK spacings, but may not. Last, but not least, some equipment will NOT work well on 50Hz power. Also, FM Radio preemphasis is different in North America and Europe. One uses 50us while the other uses 75us. To change receiver deemphasis may require a modification by a technician with special factory information. Also, power line frequency is 50Hz in some countries and 60Hz in others. Some equipment will overheat if it was engineered for 60Hz operation and run on 50Hz power lines. Some equipment uses the power line frequency as a reference for motor speed, such as turntables and tape decks. Check the label first. Step Down (230V in, 115V Out) MagneTek/Triad N1X* 50 Watts $11.83 Stancor P-8620* 50 Watts $14.16 MagneTek/Triad N3M 85 Watts $29.95 Stancor P-8630 85 Watts $43.65 MagneTek/Triad N6U* 200 Watts $25.72 Stancor P-8632 200 Watts $51.80 MagneTek/Triad N5M 250 Watts $42.60 Step Up (115V In, 230V Out) Stancor P-8637 85 Watts $43.10 MagneTek/Triad N150MG 150 Watts $49.46 MagneTek/Triad N250MG 250 Watts $54.69 Stancor P-8639 300 Watts $55.51 The Stancor and MagneTek Triad lines are carried by large electronic distributors. 20.6 Are there really good deals in country XXX? 20.7 How do I find out how much an XXX is worth? There is a "Blue Book" for used audio equipment called "Orion Blue Book-Audio". This guide lists both a wholesale and a retail value for most audio gear. Orion Research Corporation 1315 Main Avenue Suite 230 Durango CO 81301 USA 303-247-8855 http://www.bluebook.com Last I knew a guide costs $169. Each Nov, a new book is printed. After June, the old book is discounted. If you need a single quote from the Orion Blue Book, send a polite request to: al@qiclab.scn.rain.com and you may get a quote back by e-mail. 20.8 Do people really hear those differences? Who knows? They sure think that they do. 20.9 Why do people disagree on what is the best sound? There are at least three different measures of what is "Perfect Sound". All three have advocates, and all three are right, in their own way. In general, whether they admit it or not, most listeners fit into one of these three preference groups: 1. It must sound like live music. These people know what voices sound like in person, they know what instruments sound like without any amplification, and they have heard orchestras perform unaided by sound systems. They want to accurately reproduce that sound. 2. It must sound like the recording engineer wanted it to sound. The recording engineer listened with extremely good equipment to the sound coming out of the microphones, and mixed them together for what he, at that time, felt was artistically correct. It may not have been the same as live, but it was exactly what he wanted. In the extreme, people like John Fogerty used to audition his final recording mix in his truck to see how it would sound through a common, lousy stereo. 3. It must give me the most pleasure. No matter how good or bad live sounds, no matter what the recording engineer intended, if buy some equipment will give me more listening pleasure then it must be the best. With these three perspectives, it is clear that no one system will satisfy everyone. Add to that confusion the variable that everyone likes a different kind of sound, has heard live music under different conditions, and has a different idea of what the engineer intended. There is an enormous range of possibilities. Another set of reasons is that people look for different things to be right. Some want strong bass; others want male voices to sound like male voices; others want violins to sound like violins. Systems rarely do everything equally well. Speakers (in particular) are compromises. Look for the speaker where the designer had your priority first. You are perfectly right to select speakers based on YOUR personal taste. Confounding the situation further, we all say the greatest things about the stuff we already bought. To do otherwise would be to admit that we are either stupid or deaf. Still another reason is that most people haven't heard enough variations. Until you hear a system that can truly reconstruct the three-dimensional accuracy of a stereo image accurately, you may never realize that it is possible. Some excellent recordings contain enough information that with a good enough system, you can hear up-down, in-out, and left-right distinctions very clearly. However, we will never experience this until we are fortunate enough to hear such a fine recording on a very good system. Finally, some of us really can't hear much difference. We aren't deaf, but we don't have a well trained ear, don't know exactly what to listen for, and may even have slight hearing deficiencies, such as bad sensitivity to high frequencies which comes with older age, or hearing damage from listening to loud sounds (machinery, rock concerts, etc). 20.10 How do I contact the manufacturer of XXXXX? How do I get repair service on XXXXX? How do I get replacement parts? Some magazines publish lists of contact phone numbers for the manufacturers of equipment. In the US, Consumer Reports has a small listing in each issue and a more comprehensive listing in their March issue. Also, Audio Magazine has an exhaustive listing in their October "Equipment Directory". In Europe, look in "What HiFi?". You can find many addresses by reading ads in hifi magazines. You can also find out by asking at your friendly local hifi shop, especially if you've built up a relationship with them. There is a book called the "Electronics Industry Telephone Directory". It comes out yearly and is available in some libraries. Many reps from parts distributors pass them out for free. If you want a copy and are willing to pay for it, call Harris Publishing, 800-888-5900 or 216-425-9000. The directory of the Electronic Industries Association is similarly useful. You can reach the EIA at 202-457-4900. A good source for parts and service is often the manufacturer's repair center. The best way to locate one near you is to look at the literature which came with your equipment when it was new. Failing that, see the ideas mentioned above in 19.10. COPYRIGHT NOTICE The information contained here is collectively copyrighted by the authors. The right to reproduce this is hereby given, provided it is copied intact, with the text of sections 1 through 8, inclusive. However, the authors explicitly prohibit selling this document, any of its parts, or any document which contains parts of this document. -- Bob Neidorff; Texas Instruments | Internet: neidorff@ti.com 50 Phillippe Cote St. | Voice : (US) 603-222-8541 Manchester, NH 03101 USA Note: Texas Instruments has openings for Analog and Mixed Signal Design Engineers in Manchester, New Hampshire. If interested, please send resume in confidence to address above.