REVIEW INCL. Just got monoprice speaker wire in.....why do you guys reccomend this so much? - Page 7 - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 41Likes
Reply
 
Thread Tools
post #181 of 372 Old 03-11-2014, 09:37 AM
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,829
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1334 Post(s)
Liked: 751
Quote:
Originally Posted by SAM64 View Post

...probably because it's all been covered in countless other threads on conductors.
He is asking why, if what you say is true, folks keep reading and posting in this thread. It is like saying you hate a restaurant's food but go there everyday for lunch smile.gif. Surely then it is for another reason wink.gifsmile.gif.
Quote:
It's like a mechanical engineering forum with countless threads on the invention of the wheel.
Not from my point of view. I don't recall any comparison of monoprice speaker cable to other brands much less the data that is to come characterizing them. But if you have seen it, let's have the link so that I don't bother with the rest of the project.
amirm is offline  
Sponsored Links
Advertisement
 
post #182 of 372 Old 03-11-2014, 09:41 AM
 
SAM64's Avatar
 
Join Date: Apr 2011
Posts: 1,556
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Liked: 78
Quote:
It is like saying you hate a restaurant's food but go there everyday for lunch

Not from my point of view wink.gif
Quote:
I don't recall any comparison of monoprice speaker cable to other brands

Maybe you should re read the first post in this thread....you know, the one where monoprice is compared to other brands?
SAM64 is offline  
post #183 of 372 Old 03-11-2014, 09:56 AM
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,829
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1334 Post(s)
Liked: 751
Quote:
Originally Posted by SAM64 View Post

Not from my point of view wink.gif
You are here posting and reading a thread that you say is repetitive. No?
Quote:
Maybe you should re read the first post in this thread....you know, the one where monoprice is compared to other brands?
And his notion was challenged. Hence the work and expense I am going through to add some data to it.

There is a serious problem that we are addressing here: blind recommendation for a brand and products that people have not in many instances owned, or have done any testing or comparison. Or know enough technically to perform the same. It is the poster child for many such topics. Let's see if the data agrees with that assumption. I have read a lot of these "buy monoprice" threads and none have the data that we have and will have on this topic.

From my vantage point, folks are worried that some data might surface to counter their blind recommendations. Why else would they read and keep posting like you did?
amirm is offline  
Sponsored Links
Advertisement
 
post #184 of 372 Old 03-11-2014, 10:03 AM
 
SAM64's Avatar
 
Join Date: Apr 2011
Posts: 1,556
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Liked: 78
Quote:
Hence the work and expense I am going through to add some data to it.

Here's some similar data. Round wheels are better than square wheels wink.gif
SAM64 is offline  
post #185 of 372 Old 03-11-2014, 10:30 AM
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,420
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 851 Post(s)
Liked: 1251
Quote:
Originally Posted by amirm View Post

Quote:
Originally Posted by FMW View Post

And the reason it doesn't matter is that electrical current travels at about the speed of light. That means it could circle the planet 4 times in a second. Not too many human ears would notice a difference in the arrival of sound through a 6 foot wire vs a 6 mile wire or a 600 mile wire.
I know you are being facetious smile.gif. But your example of 600 mile is audible. So is 60 if my math is right. Electricity propagates slower than light but even using speed of light, 600 miles results in 3.2 milliseconds of delay in one channel. You can test your ear at this link and see how sensitive you are to interchannel delay: http://auditoryneuroscience.com/topics/time-intensity-trading. Likely depending on level, you will hear a delay of just 0.22 msec. That means 60 miles worth of delay is also audible. And depending on the wire characteristics and true propagation of delay of sound, it would be audible at shorter lengths than that.

The accuracy of our hearing system is high here because it is used to locate sounds based on delay caused between one ear being closer to the source of sound than the other. If you do this math, it comes out to something like 0.4 msec. So not surprising that 0.22 msec worth of delay is also audible.

Bet you didn't think you were going to learn this before coming to this thread. biggrin.gif

Amir, I'll bear the above in mind the next time I build an audio system in a room dimensioned in 100's of miles. ;-)

Is that a problem in your neighborhood?

I can probably figure out how to have a 50 foot speaker cable in my real, actual (not imaginary) listening room.

Letsee 50/(186,000 * 5280) = 5.0912349299446073639622026718801 E-08 seconds = 0.051 microseconds.

IOW in normal listening rooms, speaker cable length doesn't matter.
arnyk is offline  
post #186 of 372 Old 03-11-2014, 10:37 AM
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,420
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 851 Post(s)
Liked: 1251
Quote:
Originally Posted by amirm View Post

Quote:
Originally Posted by arnyk View Post

There is some hope for this one that ratchets.
And a lot more hope for this one:
41BE08ebs6L._SX300_.jpg

smile.gif

Now combine that with Ancor's adhesive lined, heatshrink connectors and you have a weather sealed connection:

0010411_Adhesive_Lined_Heat_Shrink_Ring_Terminals_450.jpeg

This is all I use in marine environment. These Ancor parts are much more expensive than the stuff in auto parts store. But when your life depends on it, you don't want to do anything less. Where I live, you get hypothermia if you fall in the water in less than half hour even in summer! You want that boat running as best as you can.

So Amir, you're of the opinion that your life doesn't depend on any of the parts in your car?

The current scandal over GM's ignition switch recall might be instructive - 13 deaths by means of a bad electrical connection with no boats in sight!
arnyk is offline  
post #187 of 372 Old 03-11-2014, 11:02 AM
FMW
AVS Forum Special Member
 
FMW's Avatar
 
Join Date: Jun 2007
Posts: 7,480
Mentioned: 13 Post(s)
Tagged: 1 Thread(s)
Quoted: 1654 Post(s)
Liked: 1711
Included in my package from Monoprice today was.....TaDa!, a 50 ft. spool of 12AWG oxygen free copper 2 conductor speaker wire.

monoprice12awg.jpg

I don't encounter any issues. It is UL listed. It is more than heavy enough for a couple of 12 foot lengths of speaker wire. It has a blue line printed on one conductor to help keep them from getting confused. It doesn't look any better or worse than similar wire one would buy anywhere else. The only difference I can see is that it only cost $15.13. It might be thinner than some. Hard to say. Doesn't matter to me. Time to go stripping and connecting.
FMW is offline  
post #188 of 372 Old 03-11-2014, 12:03 PM
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,829
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1334 Post(s)
Liked: 751
Quote:
Originally Posted by arnyk View Post

So Amir, you're of the opinion that your life doesn't depend on any of the parts in your car?
No I am not of that opinion. The risks however in a boat are way, way higher than cars. Most boats are built by tiny companies with many flaws. I bought a new 32 foot boat once and I made a list of safety items that I fixed on it. It went for three pages. I gave that to the president of the company and he was horrified. He doubled my warranty and thanked me for all the fixes. At boat shows, no matter what brand of boat, I can find safety faults in one look behind the panels or in the engine compartment. My current boat being the exception. There is just no oversight in recreational boat building other than some basics by the coast guard. Folks just look at how pretty the boat is and sign on the dotted line.

I had my family in the 32 foot boat once and while we were fishing with my son at the helm, it completely lost its steering. You could turn the wheel all you wanted and it did nothing. I was among a dozen smaller boats fishing and had real chance of hurting them by running over them. I jumped into the engine compartment and wouldn't you know, a big wave comes and a ton of sea water hits the hot engine. Here I am in this engine room with my face a few inches from the hot and steaming engine, being showered with sea water and rocking left and right, trying to figure out why the steering had failed. You know what the problem was? A tiny set screw that had loosened itself due to vibration and lack of locktight to keep it from doing so. This tiny screw jeopardized my family's life and that of others. I have not had any experiences like this in cars.
amirm is offline  
post #189 of 372 Old 03-11-2014, 12:05 PM
AVS Forum Special Member
 
Glimmie's Avatar
 
Join Date: Sep 2000
Location: Los Angeles, CA
Posts: 9,184
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1100 Post(s)
Liked: 1021
Quote:
Originally Posted by arnyk View Post


There is some hope for this one that ratchets:


That's what I use except mine isn't from Harbor Freight. It's a Pallidin and cost about $100 with dies. You also need good connectors. I like 3M brand. I have tried some no-name brands from a surplus store and they pull off even when crimped with this good crimper.
Glimmie is offline  
post #190 of 372 Old 03-11-2014, 12:34 PM
AVS Forum Special Member
 
Colm's Avatar
 
Join Date: Aug 2002
Posts: 4,649
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 97
Quote:
Originally Posted by FMW View Post

It might be thinner than some. Hard to say. Doesn't matter to me.
Sure cannot tell from the label. 12 AWG implies 3.3mm cross-sectional diameter. 3.0 mm sq cross-sectional diameter listed on the label. 87 strands of .2mm diameter wire give a cross-sectional diameter of 3.14 mm sq. Close maybe? But at the lengths you are using, it won't make a difference. It is nice that the spool has a UL hologram. I wonder if the Chinese are forging those yet. FWIW monoprice has had problems with network cable with forged UL listings that did not have the required flame retardant chemicals in the sheath.
Colm is offline  
post #191 of 372 Old 03-11-2014, 12:36 PM
AVS Forum Addicted Member
 
Ratman's Avatar
 
Join Date: May 2002
Location: Collingswood, N.J.
Posts: 19,673
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 2510 Post(s)
Liked: 2326
And now we are discussing electrical systems/wiring in boats? rolleyes.gif



If you can’t explain it simply, you don’t understand it well enough – Albert Einstein
Ratman is offline  
post #192 of 372 Old 03-11-2014, 12:39 PM
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,829
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1334 Post(s)
Liked: 751
Quote:
Originally Posted by Colm View Post

Sure cannot tell from the label. 12 AWG implies 3.3mm cross-sectional diameter. 3.0 mm sq cross-sectional diameter listed on the label. 87 strands of .2mm diameter wire give a cross-sectional diameter of 3.14 mm sq. Close maybe? But at the lengths you are using, it won't make a difference. It is nice that the spool has a UL hologram. I wonder if the Chinese are forging those yet?
They forge them left and right. Same with CE mark. See the video of the Apple chargers I post earlier.
amirm is offline  
post #193 of 372 Old 03-11-2014, 01:16 PM
FMW
AVS Forum Special Member
 
FMW's Avatar
 
Join Date: Jun 2007
Posts: 7,480
Mentioned: 13 Post(s)
Tagged: 1 Thread(s)
Quoted: 1654 Post(s)
Liked: 1711
Whatever. It works just fine. I can't imagine wanting to spend more than $15.13 for a 50 spool of wire when this is available.
FMW is offline  
post #194 of 372 Old 03-11-2014, 01:31 PM
AVS Forum Addicted Member
 
Ratman's Avatar
 
Join Date: May 2002
Location: Collingswood, N.J.
Posts: 19,673
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 2510 Post(s)
Liked: 2326
What did Monoprice do to you that created this obsession? eek.gif

And... the OP hasn't been back to AVS for a week... since his last post.



If you can’t explain it simply, you don’t understand it well enough – Albert Einstein
Ratman is offline  
post #195 of 372 Old 03-11-2014, 01:42 PM
AVS Forum Special Member
 
Glimmie's Avatar
 
Join Date: Sep 2000
Location: Los Angeles, CA
Posts: 9,184
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1100 Post(s)
Liked: 1021
Quote:
Originally Posted by Colm View Post

It is nice that the spool has a UL hologram. I wonder if the Chinese are forging those yet.

Did the Sun rise this morning? Same answer!
Glimmie is offline  
post #196 of 372 Old 03-11-2014, 04:09 PM
AVS Forum Special Member
 
Skytrooper's Avatar
 
Join Date: Nov 2010
Location: Baden, Pa.
Posts: 1,283
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 412 Post(s)
Liked: 397
Good point. This thread went off in many different directions. While there is a lot of info here, we must learn to stick to the main topic.

Meant to quote Ratman. Having trouble learning my new I Phone.

TV - LG 65B7P OLED / Receiver - Yamaha RX-A1040 7.2 / Blu Ray - Oppo BDP-83 / Turntable - Technics SL-3300 / Cable Box - Comcast X1 V4 4K /L & R Paradigm Studio 20 V3
Center - Paradigm CC-470 V3 / 4 Surrounds - Paradigm SA-15 V3 In Walls
Subwoofer 1 - Sunfire HRS-12 / Subwoofer 2 - Paradigm PW-2100
Skytrooper is offline  
post #197 of 372 Old 03-11-2014, 08:03 PM
AVS Forum Special Member
 
acras13's Avatar
 
Join Date: Mar 2011
Location: Los Angeles , CA
Posts: 1,072
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 322 Post(s)
Liked: 306
Quote:
Originally Posted by SAM64 View Post

it doesn't matter...much like the majority of this thread.

There is so much technology that could be discussed in these fora, but it always comes down to pages and pages of useless discussion about conductors.

Quote:
Originally Posted by SAM64 View Post

...probably because it's all been covered in countless other threads on conductors.

It's like a mechanical engineering forum with countless threads on the invention of the wheel.

Quote:
Originally Posted by SAM64 View Post

Here's some similar data. Round wheels are better than square wheels wink.gif

SAM64 , got it , you don't want any discussion of any topic that has ever been covered before . I'm sorry I saw an active topic running and asked a few questions of people who seemed to have some knowledge they were willing to share . Thanks for the insight on the wheels though , I didn't believe Mythbusters when they tested square wheels ( oh no , the square wheel topic has already been covered!)
Maybe I'm crazy , but when I come across a topic that I have no interest in , I just move on , maybe I should use your technique to be more efficient and valuable to the community. Happy to give you another reason to post in this pointless thread .
amirm likes this.

Turn that $*!# UP!! --Beethoven
acras13 is offline  
post #198 of 372 Old 03-11-2014, 08:06 PM
 
SAM64's Avatar
 
Join Date: Apr 2011
Posts: 1,556
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Liked: 78
Quote:
I'm sorry I saw an active topic running and asked a few questions of people who seemed to have some knowledge they were willing to share .

You seem to think I was only addressing you, you're not that special, get over it.
SAM64 is offline  
post #199 of 372 Old 03-11-2014, 08:47 PM
AVS Forum Special Member
 
acras13's Avatar
 
Join Date: Mar 2011
Location: Los Angeles , CA
Posts: 1,072
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 322 Post(s)
Liked: 306
Quote:
Originally Posted by Glimmie View Post

Did the Sun rise this morning? Same answer!
Really doesn't matter that much if the UL stickers are forged or not , U.L. listing isn't what it used to be , seems like as long as you pay your fee , you get your sticker

Quote:
Originally Posted by SAM64 View Post

You seem to think I was only addressing you, you're not that special, get over it.
I didn't say or insinuate you were only talking to me , and the second part of your comment , ironic.

Turn that $*!# UP!! --Beethoven
acras13 is offline  
post #200 of 372 Old 03-11-2014, 08:50 PM
 
SAM64's Avatar
 
Join Date: Apr 2011
Posts: 1,556
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Liked: 78
Quote:
I didn't say or insinuate you were only talking to me

Then why quote and respond to me? Do you know what ironic means?
SAM64 is offline  
post #201 of 372 Old 03-11-2014, 09:38 PM
AVS Forum Special Member
 
acras13's Avatar
 
Join Date: Mar 2011
Location: Los Angeles , CA
Posts: 1,072
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 322 Post(s)
Liked: 306
Because you were directly talking to me in the quoted text. You are showing that I have a better grasp on the definition then you do . I would link to the definition for you , but I know how you hate to see anything that has already been posted .
To stop being rude to others in this thread , I will refrain from any more dialog on this topic in the thread . I am sorry to all and thanks to those who have informed and contributed .

Turn that $*!# UP!! --Beethoven
acras13 is offline  
post #202 of 372 Old 03-11-2014, 10:25 PM
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,829
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1334 Post(s)
Liked: 751
Quote:
Originally Posted by acras13 View Post

Really doesn't matter that much if the UL stickers are forged or not , U.L. listing isn't what it used to be , seems like as long as you pay your fee , you get your sticker
It is worse than that. They put the UL mark on the device even though they have never tested it. Unless it is a manufacturer you know and trust, the mark has no meaning.
amirm is offline  
post #203 of 372 Old 03-11-2014, 10:28 PM
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,829
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1334 Post(s)
Liked: 751
Quote:
Originally Posted by SAM64 View Post

Here's some similar data. Round wheels are better than square wheels wink.gif
What you saying? That there are better wires than monoprice? How do you know that is or isn't the case?
amirm is offline  
post #204 of 372 Old 03-11-2014, 11:57 PM
AVS Forum Special Member
 
acras13's Avatar
 
Join Date: Mar 2011
Location: Los Angeles , CA
Posts: 1,072
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 322 Post(s)
Liked: 306
Quote:
Originally Posted by amirm View Post

It is worse than that. They put the UL mark on the device even though they have never tested it. Unless it is a manufacturer you know and trust, the mark has no meaning.
Exactly what I meant . You pay the fee to be listed and the burden of testing is on the manufacturer , the same way D.O.T. "certifies" helmets. They only test AFTER a deficiency has been found by someone else.

Turn that $*!# UP!! --Beethoven
acras13 is offline  
post #205 of 372 Old 03-12-2014, 10:15 AM
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,829
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1334 Post(s)
Liked: 751
Quote:
Originally Posted by arnyk View Post

It is true that some may lack the technical discernment required to appreciate technical work at a certain high level.
Thanks for the answer Arny. I am puzzled by this sarcastic remark though. The devil is in the detail when it comes to measurement accuracy. As I will explain, the circuit "at high level" is trivial. And your post lacks much of the detail necessary to ascertain the accuracy of your measurements.
Quote:
The graph is self-evident to most people who are aware of the technical issues.
Nothing of the sort. There was a professional audio interface involved in the measurement, but since it is well known that those devices are not calibrated as voltmeters, a regular laboratory Fluke voltmeter and precision resistors were used for that purpose. I also have long had two Hewlett Packard AC voltmeters on hand for the purpose of confirming the results.
Passive, following good measurement practice.
Um, this was done 14 or so years ago. No idea. My lab's inventory includes several complete series of of precision resistors of various wattages. I picked something that was appropriate, no doubt.
I appreciate that but don't you have the fixture still Arny? You asked me to send you the wires so I assumed you have the fixture and could easily look up the resistor spec.

Let's see what we can tell from the general comments you are making. The typical DIY circuit for measuring small resistances such as that of our wire (measured in milliohms or thousands of an ohm) is like this:

resvi.gif

RL is our small resistance or the 12 gauge wire in this case. As the graph explains, if we know the current going through our load and the voltage across it, then we can simply use Ohms law to compute our load resistor: R = Voltage/Current.

Your fixture of course is a bit different. You don't have the battery on the left, nor does a sound card measures current. The former you did without by using the sound card output as the voltage source. To measure current, you use a "sense resistor" and measure its voltage. If one knows the resistor then dividing the voltage across from it by that value gives us the current. Which we can then plug into above formula to get our load resistance. This is what that looks like from this link which shows how you can build one with a voltmeter: http://www.instructables.com/id/Simple-Low-Resistance-Tester-Milliohmmeter/

FHYR82JH3Z3C6G6.MEDIUM.jpg

R1 is the sense resistor. Hopefully now everyone can follow along. I asked you how much current was going through the sense resistor and you said:
Quote:
Very little.
That is problematic when it comes to accuracy. If very little current is going through our 12 gauge wire and it has very little resistance itself and we multiply those two together, we get a well, very, very small voltage. smile.gif Measuring small voltages is prone to accuracy error. Professional milliohm meters us as much as 20 amps with 2 amps being the typical value to make sure sufficient voltage develops across the load to measure its voltage accurately. Your sound card is designed to sample a fixed voltage level of 1.5 to 5 volts. If you reduce its maximum to say, 1 millivolt, you throw away 99.9% of its range and relying on the accuracy of 0.1% of its A/D.

Since you used a passive circuit, just the resistor with the sound card being the voltage supply, you had no choice but to pick a large resistor and hence, small current. This is why the "right" answer to my question would have been an active circuit with its own power source and preferably op-amps on output and input to buffer the sound card and not let its internal impedance impact the test.

Note that having a multimeter would not have helped you calibrate this device as your multimeter would not have been capable of measuring sub 1 ohm correctly or else, you wouldn't need to build this circuit. The accuracy of meters once you get below 10 ohms is poor as the lead resistance and contact can be in the order of 0.5 ohm.
Quote:
Probably around 1%.
Unless you can provide the full details and analysis of how many effective bits you had to measure that low voltage, you can't state the accuracy.
Quote:
That's one of the advantages of using an audio interface rather than a meter. I had ready access to a wide band FFT of the voltages applied and measured. They were very clean.
Your used a sampling rate of 96 Khz meaning your bandwidth was just 48 Khz. That doesn't match the definition of any engineer's "wide bandwidth." smile.gif As to it being clean here is your transfer function graph:



I see that you used 20 run averaging. You data must have been pretty volatile to require that much averaging. And where did you plug in the sense resistor value in SpectraLab?
Quote:
It is true that for some jealous people, no good deed goes unpunished.

I had an old school education in testing and measurement. Give me a single precision resistor or precision voltage source and I can follow my formal training to leverage it into a wide variety of accurate measurements. Remember, my first electronics courses were based on vacuum tubes, with solid state added because it seemed to be the coming thing! ;-)
I don't understand the reference to "no good deed." You are saying that you were helping me say that cheap wires are under spec? If so, I don't need that kind of support. I am interested in the correct data. If it turns out that low cost wire does the job I would be as happy as anyone else. I am not after any certain outcome.

As to the second comment, that concerns me again. You say you want a voltage source and a resistor. Your sound card is not a proper voltage source as it is not designed to drive very small loads. Its output impedance is likely 50 to 100 ohms making it a very poor "voltage source." That limits your choice of that sense resistor.

As to needing precision resistor, that is wrong Arny. No precision is required at all! Why? Because we can simply measure its resistance with our multimeter. Unlike our load, the sense resistor is a much higher value like the 220 ohm one in the above circuit. Our standard multimeter can measure the resistance of a 220 ohm resistor with very high accuracy. And that is all we care about. Whether the manufacturer rates the resistor as 1% or 10%, matters not because that simply says how much variation can be in the value of the resistor from its advertised value. We can measure it and know what it is. If it is 230 or 222 ohms matters not. As long as we know its value we can divide the voltage across it by the measured resistance and get our current.

There is one potential problem though. If you push too much current through that resistor as to get a higher voltage across our load (and hence increase the accuracy of that voltage measurement), the resistor will heat up and that changes its value from what we measured with our multimeter. This is why I asked you about the temperature coefficient of the resistor.

It is for these reasons and others I have not mentioned that you don't want to build your own fixture unless you are aware of all the things that can throw off its accuracy. Measuring it with a sound card adds additional problems. This is why I am using a proper milliohm meter. Using PC for measurements is fine as a hobbyist but not as authoritative data to put forward.
amirm is offline  
post #206 of 372 Old 03-12-2014, 11:41 AM
AVS Forum Special Member
 
Glimmie's Avatar
 
Join Date: Sep 2000
Location: Los Angeles, CA
Posts: 9,184
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1100 Post(s)
Liked: 1021
Quote:
Originally Posted by amirm View Post

It is worse than that. They put the UL mark on the device even though they have never tested it. Unless it is a manufacturer you know and trust, the mark has no meaning.

Well that's news to me. I'm not disputing it because I really don't know. But I always thought UL was pretty thorough.

Now I do know that in the early 1990s UL came out with a professional equipment certification. This was driven largely by the IEEE and I was in a SMPTE group that represented the TV and movie industries. It's one thing to submit 10 toasters or irons to UL and know you will never get them back as they are destructively tested. But when you are talking about a limited market $500K supercomputer, CNC machine, brodacast TV camera, that's a different matter. So these products were largely non listed. This compromise allows a reasonable non-destructive safety test realizing that no professional user of these products is going to try and use them in a swimming pool.
Glimmie is offline  
post #207 of 372 Old 03-12-2014, 12:05 PM
AVS Forum Addicted Member
 
DonH50's Avatar
 
Join Date: Feb 2010
Location: Monument CO
Posts: 12,479
Mentioned: 72 Post(s)
Tagged: 0 Thread(s)
Quoted: 3349 Post(s)
Liked: 3500
And you might be amazed and repelled at the logos that have been forged and mass-produced, and not just by Chinese factories... Counterfeit parts and certs are a huge problem in the electronics and many other industries.

I for one think it's great that Amir has the funds, equipment, energy, and time to perform more tests. Ditto the work Arny and others have done. Current data is always good to have, and different testers to confirm and validate results from multiple sources is something I always like to see. Coming from the R&D world, a lot of times claims are not accepted until replicated by another party. I am very curious to see how the measurements work out.

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
DonH50 is offline  
post #208 of 372 Old 03-12-2014, 12:22 PM
Senior Member
 
bldxyz's Avatar
 
Join Date: Jan 2005
Location: San Francisco Bay Area
Posts: 279
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 10
I wish I had the time to read all 7 pages of this thread. How did this all turn out?

Did someone do some scientific testing on the Monoprice wire versus another? I thought at some point that was going to happen.

I've just done a lot of wiring with Monoprice In-Wall wiring. I'm eager to know if I have made a grand mistake... rolleyes.gif
bldxyz is offline  
post #209 of 372 Old 03-12-2014, 12:54 PM
AVS Forum Addicted Member
 
Ratman's Avatar
 
Join Date: May 2002
Location: Collingswood, N.J.
Posts: 19,673
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 2510 Post(s)
Liked: 2326
Quote:
Originally Posted by bldxyz View Post

I wish I had the time to read all 7 pages of this thread. How did this all turn out?
Read 'em all! It's a hoot!
Amirm will post his results as soon he completes testing. I just hope he's "honest" with the results and comparisons.



If you can’t explain it simply, you don’t understand it well enough – Albert Einstein
Ratman is offline  
post #210 of 372 Old 03-12-2014, 02:12 PM
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,829
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1334 Post(s)
Liked: 751
Quote:
Originally Posted by bldxyz View Post

I wish I had the time to read all 7 pages of this thread. How did this all turn out?

Did someone do some scientific testing on the Monoprice wire versus another? I thought at some point that was going to happen.
I am almost there with the measurements. Waiting for a couple more wire samples to arrive. One is on slow boat from China (Parts Express) even after paying something like $9 for shipping it has been a week I think and still not here.
amirm is offline  
Sponsored Links
Advertisement
 
Reply Audio Theory, Setup, and Chat

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off