412 Cab Rewiring

Hi, I'm Mike Sullivan. Welcome to Guitar Tech. How to do it yourself. Hello, today I am going to rewire this Karvin G412B cabinet which is a really nice cabinet and they're on sale right now at Karvin.com They're very nice sounding cabinets. This is a bottom and it's not wired to suit my needs. I bought it so that I could save $150 and then rewire it for what I need. I'm running a Marshall 9100 to drive it and it's an 8 ohm cabinet at 280 watts. What I need it to be is a stereo cabinet at 16 ohms and 140 watts a side. When it goes into stereo mode it's running 4 ohms so I figure it would be cheaper to rewire the cabinet than to take my Marshall power amp in and have a technician do what he needs to do to make the power amp kick out 4 ohms. I figure that's going to be way more expensive. So this way I just move some wires, use some solder and I'll have a cabinet that meets my needs. As you can see I did remove the front grill because this is a front loaded cabinet so in order to get to the speakers you've got to remove the grill. I have already removed basically the guts and relabeled everything so that if I want I can reconvert this cab back to its stock manufacturer configuration. There's a little motherboard that comes with this right here. And your speakers just plug in right here. So it's like I believe it was like a series parallel type situation that they were doing and then there's a switch that allows you to switch from 4 ohms to 8 ohms. So I'm just going to use straight jack to two series speakers. And this I can hang on to so if I want to change it or if I decide to just let it go and sell it later then I can do that. But it was important to relabel the changes so that you don't go by the specs that were on the cabinet. So this is going to be wired left and right at 16 ohms and 140 watts per side stereo. So I can use the cabinet in a variety of ways. By doing that I can run two 212 rigs at the same time because the 9100 Marshall is actually two separate 50 watt power amps which is buried down there. So it's actually two separate rigs. I don't know how much you know about these but they're really nice rigs. As you can see I'm running a Boss GX7100 processor and a Digitech 2101 processor. So if I want I can run each one of them into each side of the amp running into the the 412 as two separate guitar rigs if I wanted to. Okay now the carbons are wired parallel so they run the hots of the left side to one clip and they run the hots to the right side to one clip and then the negatives they do the same thing. Since I can't use this configuration I need to clip these off and then I will strip the wires and use solder to connect them the way I need them to be. I've laid out the wiring and it's a simple wiring to do. You're just going to come off of the left side jack the hot lead is going to connect to the hot lead on the speaker top speaker. I come off the negative lead of the top speaker connecting to the positive lead of the bottom speaker so the signal flows in one side goes to the coil comes out connects to the hot side of the bottom speaker goes to the coil comes out and then connects returning to the the jack and that's it that's all there is to series wiring. And then I do it on both sides and I omit any parallel wiring here because I don't want this to be used as an extension cabinet I just want two two twelve cabinets within one box. That's how I want it wired. So now all I need to do is solder it and put it back together. So anybody that's interested in doing something like this kind of conversion I hope that you found this helpful. It's easy enough to do. The total cost of this was just a little over six dollars for the two jacks at my local music store. And that's it. That and some solder. Well thanks for watching and see you next time on Guitar Tech How to do it yourself.