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Made by Monkeys

Snafus With the Speakers

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William K.
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Platinum
Speaker failures
William K.   11/1/2012 5:42:23 PM
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The choice of a poor quality glue is as much a design flaw as any other. Of course, a much better design would have included a shape detail that would hold the magnet in the correct position. And some speakers haveincluded a sheetmetal stamping that serves no purpose except to assure that the magnet stays in the correct position. 

The fact is that delivering top quality usually means providing more than only just enough to meet the specifications. I am fully aware that there are those that will challenge this concept, and claim that just barely meeting specifications is all that it takes, but those folks only know about maximizing profit and probably are unaware of what actual high quality consists of.

Frank Karkota
User Rank
Iron
Speakers and quality control
Frank Karkota   11/1/2012 7:33:50 PM
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One of the hardest parts of manufacturing is quality control, especially for a small company.  As noted, the cabinets were made of oak.  The saw mills do not have tight quality control and thus occassionally wood is slightly thicker.  This was too rare to make a fuss and took only minutes to correct.  Occassionally mistakes are made and must be corrected.  

 

Regarding the speakers, they appeared to be very high quality.  The problem could have been poor glue, or improper application.  It could also have been too cold when the speakers were made.  Or maybe the manufacturer was just sloppy.

 

Getting good parts is not as easy as it seems.  A number of years ago, I bought 10,000 capacitors from a highly reputable US manufacturer.  They were used for general bypass and coupling.  After six months of use, they started leaking (internal resistance dropped) and the commercial receivers started failing to the point where the system failed.  It was expensive to recall and replace perhaps 5000 capacitors.  I have never had that happen with Chinese parts.

 

Regarding documentation, with a staff of four employees, we did not have time to document everything, especially if it was a rare occurance, such as cabinets out of tolerance.  Nobody is perfect!!!

Ratan1
User Rank
Iron
Need to Apply Statistics
Ratan1   11/2/2012 11:58:27 AM
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Get the dimension of the speakers, both mean and standard deviation, and makes sure that the inside dimension of the cabinet is at least mean + 3 sigma. This will fix the root cause of the problem.

Rob Spiegel
User Rank
Blogger
Re: Speakers and quality control
Rob Spiegel   11/2/2012 2:37:30 PM
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Frank, when you had the problem with the capacitors did you investigate to determine whether the capacitors were counterfeit? This sounds like a classic counterfeit problem.

Frank Karkota
User Rank
Iron
Re: Capacitors
Frank Karkota   11/2/2012 7:32:54 PM
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This was back in the mid 1990s and I got the capacitors directly from the manufacturer--no middleman. Of course, they might have outsourced the parts.  It was one of the most reputable makers of capacitors in the world.  You just can't tell!

I have never had that problem with Chinese made capacitors.  The company is still in business, so what happened to me must have been an aborration, a very costly aboration.

Rob Spiegel
User Rank
Blogger
Re: Capacitors
Rob Spiegel   11/5/2012 2:00:52 PM
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Thanks Frank. Counterfeit parts can come through reputable dealers or suppliers when the accept returns. Also, I would guess the legitimate parts made in China would be fine. So the problems I hear about are not from all Chinese parts, just the counterfeit parts.

Cadman-LT
User Rank
Platinum
Re: Capacitors
Cadman-LT   11/5/2012 2:41:17 PM
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I agree. You hear about counterfeit parts all the time. It's almost like the black market for parts. You hear about it alot with computer chips.

Rob Spiegel
User Rank
Blogger
Re: Capacitors
Rob Spiegel   11/5/2012 4:09:36 PM
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Hi Cadman-LT. Yes, counterfeiting is widespread. It takes a wide range of forms. In some cases, a factory that is making components for a U.S.-based company during the day shift will run a nightshift where they make the same components to sell as counterfeits. So the parts are good, but they've stolen the IP from their customer.

cookiejar
User Rank
Gold
Re: Making it work
cookiejar   11/6/2012 7:33:17 AM
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It seems obvious in hindsight that the reason for the really good price on the speakers was that they had a hidden flaw, which was discovered after the horse had left the barn.   

If it seems too good to be true, it usually is. 

Buyer beware etc. etc. 

Q.C. and testing on a limited budget are hit and miss when you don't know what you're looking for.  I'm sure in the future, any speakers will be tested for magnet retention.

Battar
User Rank
Platinum
Re: Capacitors
Battar   11/7/2012 3:29:08 AM
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Why do the counterfeit on the night shift? Daylight is good, too. Our former CEO once worked for a company which outsourced production to a nameless country (whose national flag is mostly red in color), and on a visit to the factory they discovered that alongside parts being produced with the company logo, identical parts were being produced with no logo. They probably went to the internal market, not export.

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