Internet Info 1997 December/Internet_Info_CD-ROM_Walnut_Creek_December_1997.iso/faqs/rec/answers/AudioFAQ/part13

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Subject: FAQ: rec.audio.* Misc 5/97 (part 13 of 13)
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Date: 28 Sep 1997 09:06:40 GMT
Organization: Unitrode Corp.
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Summary: Answers to common questions about audio equipment, selecting,
  buying, set-up, tuning, use, repair, developments, and philosophy.
X-Last-Updated: 1997/07/31
Originator: [e-mail]
Xref: senator-bedfellow.mit.edu rec.audio.tech:57585 rec.audio.opinion:130212 rec.audio.misc:39681 rec.audio.marketplace:129397 rec.answers:34323 news.answers:113258

Archive-name: AudioFAQ/part13
Last-modified: 1997/7/31
Version: 2.12

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 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 [e-mail].  Note: this address is
    spam-blocked.  Remove the "xyz" before using.

    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
    NAD            508-429-2525
    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 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.  North America uses 50us while Europe uses 75us.  To
    change receiver deemphasis may require a modification by a
    technician with special factory information.

    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
    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:
        [e-mail]
    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.

Note: My e-mail address in this FAQ is "Spam-Blocked".  Remove "xyz" to use.
--
Bob Neidorff; Unitrode Corporation  |  Internet: [e-mail]
7 Continental Blvd.                 |  Voice   : (US) 603-429-8541
Merrimack, NH  03054-0399 USA       |  FAX     : (US) 603-429-8564

Note: Unitrode Corporation has openings for Analog and Mixed
Signal Design Engineers in Merrimack, New Hampshire.  If
interested, please send resume in confidence to address above.