# Which speaker terminal is +ive?



## allthumbs56 (Jul 24, 2006)

Right, so I pulled an older Celestion G12T75 from the closet and the terminals aren't marked. I have another, labeled as a G12t75 (although it looks a bit different) and the +ive is marked. Can I trust that they'd be the same? Is there a way to test it?


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## jb welder (Sep 14, 2010)

Touch a 9V to the terminals, just momentary, don't hold it on there.
With batt + to speaker +, cone should move outward.
At least for probably 90% or more spkr makers. Some are reversed (some JBL for sure). 
To be 100% sure verify it matches your other celestion.


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## allthumbs56 (Jul 24, 2006)

Thanks JB


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## davetcan (Feb 27, 2006)

The red one, or the one with the little "+" beside it.

Does that help


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## bzrkrage (Mar 20, 2011)

davetcan said:


> The red one, or the one with the little "+" beside it.
> 
> Does that help


Cheeky bugger! Been a staff member, what? 5 minutes?!? Already sarcasm!


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## davetcan (Feb 27, 2006)

Well I could have posted this but JB has it covered 

How can I tell which terminal is positive and which is negative? | Eminence Speaker


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## allthumbs56 (Jul 24, 2006)

davetcan said:


> Well I could have posted this but JB has it covered
> 
> How can I tell which terminal is positive and which is negative? | Eminence Speaker


Except that Eminence suggests a 1.5v battery and JB suggests a 9v.

Which voltage will give me a creamier midrange?


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## Dorian2 (Jun 9, 2015)

Will the speaker blow if you actually hold the 9V there? Just curious and unwilling to test this.


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## davetcan (Feb 27, 2006)

If 1.5v is enough to move the cone I'd be doing that. JB did say to just touch it momentarily @ 9v though. If you're looking for buttery tone stay away from rechargeables.


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## gtrguy (Jul 6, 2006)

Dorian2 said:


> Will the speaker blow if you actually hold the 9V there? Just curious and unwilling to test this.


Possibly. The DC voltage pushes the cone in one direction (unlike an AC voltage which moves it back and forth) once the cone can't move any further the voice coil is just going to start heating up.


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## oldjoat (Apr 4, 2019)

and that's the reason to just "touch" the terminals and see which way the cone moves ...


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## allthumbs56 (Jul 24, 2006)

davetcan said:


> If 1.5v is enough to move the cone I'd be doing that. JB did say to just touch it momentarily @ 9v though. If you're looking for buttery tone stay away from rechargeables.


Should it be dying ala the Eric Johnson fable?


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## davetcan (Feb 27, 2006)

allthumbs56 said:


> Should it be dying ala the Eric Johnson fable?


ooohhhh, sounds like I have some reading to do.


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## jb welder (Sep 14, 2010)

Yes, it has to be the classic Eveready with the black cat on it. 
I suggested 9V as often the terminals on the speaker match the spacing of the battery terminals. With a 1.5V you are going to have to use at least 1 wire to connect. 
As noted by others, the potential hazard (potentially hazardous potential?  ) is why I said to only touch briefly.


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## allthumbs56 (Jul 24, 2006)

Thanks all for your help. As it turns out 1.5v is not enough for my eyes to determine the direction of travel so I ended up using a 9v as per jb's advice. It was a Durocell which is Eric Johnson's preferred brand. It produced a lovely, creamy thud without any harshness in the upper mids.


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## High/Deaf (Aug 19, 2009)

A 9 volt battery across a 4 ohm speaker with a DC resistance of say 3 ohms (worst case scenario) would draw around 3 amps and dissipate around 20 watts. Certainly enough to get hot after a bit of time, but for a couple of seconds, not an issue. As @jb welder said, 9V's are convenient because they terminal spacing is about bang on. And you can pull one out of your tuner or a pedal in a pinch.


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## oldjoat (Apr 4, 2019)

3 amps out of a 9V ? cough, cough, snort ... 3, 2, 1 , 0
the 9V internal resistance would limit that in a real hurry . 

but we get that it should only be touched for a second .


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## allthumbs56 (Jul 24, 2006)

Speakers are installed and just tested tonight. Sounds pretty good. Proof will be in the puddin' at Saturday's gig. Thanks again for all the assistance.


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## High/Deaf (Aug 19, 2009)

oldjoat said:


> 3 amps out of a 9V ? cough, cough, snort ... 3, 2, 1 , 0
> the 9V internal resistance would limit that in a real hurry .
> 
> but we get that it should only be touched for a second .


Yes, there are physical limitations to the theory. It may get close to that for a brief moment, though. It's also unlike a 9V battery will source 20 watts for very long but I would still consider that in any design (better safe than sorry). I betcha a 9V battery will pop a 3A fuse put right across it.


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## oldjoat (Apr 4, 2019)

I concur


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