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Which is plus and which is minus?? help
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korsager View Drop Down
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    Posted: 19 July 2012 at 12:58pm
I just received me Tripath amp from China. 

It came with a wire that is to be connected to a battery, however, I cannot see which wire is plus and which is minus. 
Both wires are black, but one of them has a little white stripe on it.

The wire is similar to the one in the picture beneath. 

Can anybody tell me what wire is minus/plus? No fuses, so I only got one chance :)
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use voltmeter set to DC.
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studio45 View Drop Down
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There is no convention for this - if you ask me, obviously the stripe should indicate negative - but every Chinese mfr does whatever they like with it, basically. 
You will need some kind of voltmeter to check. Or an LED, which will only light when it's the right way round (lead next to flat on body goes to negative)
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slaz View Drop Down
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Points: 2713 		Post Options Post Options   Thanks (0) Thanks(0)   Quote slaz Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2012 at 3:20pm
Originally posted by studio45 studio45 wrote:

the stripe should indicate negative


Oh. I'd say the opposite LOL

But seriously you need to get yourself a test meter of some sort .... even a little cheapie one ...
In this case do as others have said, or just cut the cable off and use the meter in resisitance-checker mode with the barrel plug. Unless the Chinese have REALLY been at it, you can assume centre-tip = +ve .... so whichever half of the cable that shorts to is +ve.
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Points: 2276 		Post Options Post Options   Thanks (0) Thanks(0)   Quote infrasound Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2012 at 4:22pm
It should have a diagram on the power supply, underneath the prongs.

Although, your amplifier should have a diode on the power supply input - ensuring no damage is done if connected incorrectly.

If so, just connect it up whichever way - if no sound / power LED, try the other way!
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Both my lepai 2020s came with the same, unlabelled, power lead. I took a guess that the plain black wire would be negative, it was!
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White stripe normally = positive with these things
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Points: 2186 		Post Options Post Options   Thanks (0) Thanks(0)   Quote imageoven Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2012 at 5:47pm
Originally posted by JR.junior JR.junior wrote:

use voltmeter set to DC.

 
Every one on speakerplans should have a multimeter, even if you don't know how to use one yet, they are so cheap to buy a basic model it's daft not to own one.
 
 
Check the impedance of your drivers, continuity of cables and drivers, mains voltage level, battery or powersupply voltage level etc. etc. (and generaly impress the girls / boys with your hi tech gadgetery).
 
 
Keep pushing on, things are gonna get better.
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I´d say that the white stripe is +ve, but it shouldn´t really matter as the input should be diode protected - try it one way, if nothing, just swap. If it blows up, send it back with an angry note! Smile
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Originally posted by Earplug Earplug wrote:

I´d say that the white stripe is +ve, but it shouldn´t really matter as the input should be diode protected - try it one way, if nothing, just swap. If it blows up, send it back with an angry note! Smile


 
+1 LOL
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korsager View Drop Down
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I dont wanna blow up the amp, as it came all the way from china :P

The LED trick worked. The white one was +... Im happy

I got a multimeter, but I dont know how to determine polarity when I only got a wire?
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Originally posted by korsager korsager wrote:

I got a multimeter, but I dont know how to determine polarity when I only got a wire?

Set the red on one lead and black on the other. If the meter says -V then whatever is on the red lead is negative. It's that simple. Smile
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