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In Reply to: RE: EV Wolverine LT12 posted by somwhunw on July 01, 2009 at 18:39:25
S.
T1 should be positive and T2 negative. You can verify the polarity of a mystery woofer by attaching (momentarily) a 1.5 Volt battery to the terminals. When the positive pole of the battery is connected to the positive terminal of the woofer, the cone will jump outwards away from the magnet, and the opposite of this will happen with the reverse connection.
Paul
Not always!
JBLPro and Tannoy drivers for instance are(were) designed to react exactly the opposite way.
Both companies stated in their blurb that this is so in order to maintain absolute polarity.
JBL has not reversed polartiy on their drivers for years
Hence the qualification in my original post.
B.L.
This would seem like a simple enough thing, but it can quickly lead to confusion. Way back in the day, Ben Franklin had to decide which of the two electrodes in his experiments would be called positive. He had a 50/50 chance of getting it right, and he guessed wrong. As this applies to the present discussion, if you apply a "standard" positive voltage to one of the woofer terminals (let's forget Franklin for a now) and this terminal moves the cone away from the magnet, then what do you call, color or symbolize this terminal as? According to the link Pro Sound Guy provided, JBL picked red for negative while most of the other guys went with red for positive and black for negative. JBL later had to get their nomenclature in step with the industry. The woofer motors act the same no matter how you label the terminals. I once blew out an alternator while trying to replace the battery on a friend's Toyota. There were 2 cables: one black and one tan. The Japanese drive on the left like the English, and this Toyota had the starter on the opposite side from the battery to make way for swapping the steering, with long cables that snaked in and out of the body and obscured their origin. I thought "Black's gotta be negative, and tan is just brown mixed with white, and brown has red in it, so tan's gotta be positive". This all seemed quite logical, but I was wrong of course. Some JBL or Tannoy engineers must have been working at Toyota in the late 80's.
Another Polarity War Victim
Paul
Of course you could just open your breaker box and look at the color of the wiring.
The ot wires are black and the neutral wires are white.
LOf course there is no +- in AC, but the wires are considered by be "backwards" by all other electrical devices in which the black wires are -, low, cold etc.
Ivan
American domestic wiring code may well have inspired JBL and Toyota. Tannoy got started making budget automotive battery chargers (Tannoy is an acronym for the tantalum alloy they used for diodes) so they had a foot in both the domestic and automotive worlds. Well, ya gotta pick one or the other like Ben Franklin did.
Paul
Thanks a lot for all information.
Best Regards,
Somshunw
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