a quick and easy stupid question...

I

Ironklad Audio

New member
long story short: the input jack on my marshall 4x12 got disconnected from the speaker leads, and i need to know which lead goes on to which connection point - assuming it makes a difference.

and in case it matters, the speakers are 8 ohm, wired in parallel. i figured there would be a + and - indicator on the jack itself, but there's nada, which kind of leads me to believe that it doesn't matter...but i really don't want to fuck anything up, so i thought i'd ask my fellow home-rec'ers beforehand.
 
No no, it matters.

On most mono jacks, you can see which lead will touch which part of the chord. One lead of the jack will connect to the sleeve part, which will be the ground (-), and the other lead will connect to the tip (the angled bent part that the tip of your cord connects with when inserted), which is the signal (+).
 
Ironklad Audio said:
long story short: the input jack on my marshall 4x12 got disconnected from the speaker leads, and i need to know which lead goes on to which connection point - assuming it makes a difference.

and in case it matters, the speakers are 8 ohm, wired in parallel. i figured there would be a + and - indicator on the jack itself, but there's nada, which kind of leads me to believe that it doesn't matter...but i really don't want to fuck anything up, so i thought i'd ask my fellow home-rec'ers beforehand.
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It doesn't make any difference except to the absolute phase of the speakers, and that won't make any difference to your sound. The convention is that the part of the plug that connects to the tip of the jack is positive, and applying a positive voltage there will make your speaker cones move out/forward, but it's completely arbitrary.
 
Oh .. duh ... I was thinking he was asking about the input jack for a guitar amp--not a speaker cab. Now I see that he even says "4x12" ... I guess I was asleep.

Anyway, it doesn't really matter as long as you're consistent for each cabinet (if you're using more than one). If you're running 2 cabinets for instance, you need to make sure the speakers are moving in the same direction. This can be done by switching the leads that run to the jack or the ones that attach to the speaker.
 
if you take a 9v battery and put it across the plug with the tip to the positive all your speakers should push forward....
 
dementedchord said:
if you take a 9v battery and put it across the plug with the tip to the positive all your speakers should push forward....
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That's the convention for everyone but JBL. It's convention only, though; as long as all your speakers are in agreement it doesn't matter which way they go.
 
ggunn said:
That's the convention for everyone but JBL. It's convention only, though; as long as all your speakers are in agreement it doesn't matter which way they go.
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agreed for the most part... the only little quibble is that it's easier to set the air in motion with the compression side of the stroke... not the rarification... now personally i doubt it makes alotta difference but then again i dont see any need for $200 power cords....
 
dementedchord said:
agreed for the most part... the only little quibble is that it's easier to set the air in motion with the compression side of the stroke... not the rarification... now personally i doubt it makes alotta difference but then again i dont see any need for $200 power cords....
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Even if it did make a diff, you have no way of knowing which way the initial attack from the strings is going to push the speaker cone anyway. Many stompboxes invert your signal, for instance, and on many amps with two channels (the Fender Super Reverb, for one), one channel is inverted from the other because it goes through an extra gain stage. Absolute phase is determined by whether your signal goes through an odd or even number of gain stages from guitar to speaker, and a single stomp box can patch you through several, or none in true bypass mode. It's a coin flip.
 
famous beagle said:
Oh .. duh ... I was thinking he was asking about the input jack for a guitar amp--not a speaker cab. Now I see that he even says "4x12" ... I guess I was asleep.

Anyway, it doesn't really matter as long as you're consistent for each cabinet (if you're using more than one). If you're running 2 cabinets for instance, you need to make sure the speakers are moving in the same direction. This can be done by switching the leads that run to the jack or the ones that attach to the speaker.
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hehe "I have 2 4x12 cabinets and the amp is turned up all the way... the speakers appear to be moving when I play, but I don't hear anything" :D
 
cusebassman said:
hehe "I have 2 4x12 cabinets and the amp is turned up all the way... the speakers appear to be moving when I play, but I don't hear anything" :D
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Then you've been playing too loud for too long. Perhaps it's time to learn sign language. ;^)
 
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