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

( Part1 - Part2 - Part3 - Part4 - Part5 - Part6 - Part7 - Part8 - Part9 - Part10 - Part11 - Part12 - Part13 )
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Archive-name: AudioFAQ/part13
Last-modified: 2007/07/12
Version: 2.17

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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.

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