I bet it's been asked a thousand times by now, but I am slow. How is this wired? And is it wired correctly? 16ohm speakers in my 4x12 1960ax
Yes that's series/parallel for 16 ohms, but laid out differently. Marshall wires it so there's a left series pair in parallel with a right series pair splitable into two mono pairs, yours is wired so there's a top series pair and a bottom series pair in parallel but not splitable. Yours is okay if your jack is hardwired for 16 ohms mono. -------------------------- I can't see the polarity markings on the bottom pair. The red wire from the top left "-" should go to bottom right "-", black wire from top right "+" should go to bottom left "+". Jumper connecting the bottom speakers should go from bottom right "+" to bottom left "-". --------------------------- The standard convention is black is "-" and red is "+". Yours is backwards, so make sure it's also backwards at the jack. Yours should have the black connected to the jack tip, with red connected to the jack sleeve. (Doesn't matter if you use the cab by itself, but if black isn't connected to the jack tip yours will be out of phase with conventionally wired cabs.)
Thanks! I'll go look, I figured red and black were off. Ya you can't see the bottom ones, just have to rotate it in your head. My other cabinet is a stereo 1960a and it's even different still. I can't wrap my head around it, it's probably my brain damage.
@Headache There are two ways to wire your 4x12 cab that Marshall used. Series/parallel, and parallel/series. Both are illustrated on my page link here: http://www.scumbackspeakers.com/wire.html There are links to larger PDF files of the wiring for you to zoom in on if you download the links to your computer or whatever to make it easier to follow the wiring diagram. Parallel / series is a little more in your face for mids (subtle), while series / parallel is a little more bluesy, laid back with a touch (subtle) more bass. Just follow the red and black wiring exactly and you're good to go. Mostly I find players prefer parallel / series these days, and it's less wire as well. Both wind up at 16 ohms total load with four 16 ohm speakers. Since you know your style better than I do, pick what would work best for your tone. Good luck! Jim
Thanks Jim! And RLW59, You 2 guys are a big help! I know these Mode Fours are notorious for blowing up and being finicky with any fluctuations, I had one blow up a couple years ago... Literally from plugging into a different cabinet, so I'm really just double checking because I don't want anything bad to happen to my amp. Plus I enjoy learning as I go.
Here's my backside just for clarification. If I'm looking at it correctly, then it's out of phase ya? My jack is correct, and it's backwards the rest of the way down. I'm going to pull it all and follow a diagram.
Someone installed a stereo input jack in your cab (WTF?) but as long as you wire it in mono, no harm/no foul. The rest of your wiring looks correct. Time to fire it up! (Uh, I mean...uh...you know what I mean....)
dear, i have 4x12 g12t75 speakers in the cabinet ... each is 8 ohms. I wonder which wire to use for their parallel connection? some say 2x1.5mm2, others say 2x0.75 ......? thank you
Correct. It's known as automotive or zip wire. I get it in red & black to make it easier to wire to the right terminals. Any decent hardware store or electronics shop should have it. I get it in 500 foot rolls, but that's overkill for most.
