So, way back when, metallik gave an awesome suggestion on how to really make a Stern machine sing by addition of higher quality speakers, an external subwoofer, and Boss amplifiers.
Since he did this, a few of us have copied his setup, but details have been rather minimal with few photos and vague descriptions.
This thread hopes to turn that around, and empower other Pinsiders to duplicate metallik's setup and have their machines truly sing.
I hate to do this, but here's the mandatory "You dun screwed up" disclaimer: These instructions, photos, and videos assume you understand basic wiring component work. The work itself is nearly identical to installing a radio into a car. The equalizer is your radio, and the pinball machine is your car. If you are NOT comfortable with doing this, DON'T. I am not responsible for any damages incurred on your property if you choose to do this upgrade. I am also not responsible for any injury or death you caused. You break something - or mame, hurt, injure, or kill something/someone - blame yourself.
Ok, now that that crap is out of the way, let's begin.
So, the first thing you want to do is buy everything in this picture:
The Pyle speakers can be found here: http://www.parts-express.com/pyle-plg42-4-coaxial-speaker-pair--267-717
** - NOTE - ** - the Pyle speakers are plug and play so as long as you do not mind removing the stock Stern speaker grills. If you do not, the speaker cones extend too far out and will push against the speaker grills. If you want to leave the speaker grills in place, you'll need to devise a way to mount them with some metal spacers. I don't care about the grills, so I have not devised such a setup.
The Pyramid speaker can be found here: http://www.parts-express.com/pyramid-wx85x-8-white-poly-woofer--290-272
The Boss amplifiers (total of 2 needed, one of the translite speakers and another for the cabinet speaker) can be found all over the internet. Amazon is one good place to get them: amazon.com link »
Any basic desktop computer power supply. This one from NewEgg for about $20 should work fine: http://www.newegg.com/Product/Product.aspx?Item=N82E16817152019
** - IMPORTANT NOTE - ** Some power supplies will run with a load attached, and some won't without a load. When you get your power supply, you will want to locate the 24 pin connector. Find the solid green wire (power on), and to the immediate right or left of that wire, there will be a solid black wire (ground). You want to jumper these wires together. Basically, it acts as a fail-safe, insuring that your power supply will run with or without a load (your speakers). For a quick visual, see this diagram:
Have basic tools on hand: crimpers, wire strippers, electric twist nuts, speaker wire, insulated male and female connectors, etc.
Now, first thing to do is access the back of your Stern speaker panel, remove your old ho-hum factory speakers and install your new Pyle in the left side. Now, don't put the factory wiring back on your new speakers, no no no. Take the red w/white stripe wires and the red w/orange stripe wire and connect the two together.
From there, follow the red w/orange stripe wire, and you should see it run to a capacitor. From the other end of the capacitor, the wire should now be solid red leading to the other speaker on the right side of the machine. Now, get rid of the other factory speaker and put in your new Pyle on the right side. When removing the factory speaker, you should see the other end of the red wire we were just talking about as well as a pair of red w/black stripe wires.
Focus on the red wire first. We want to get this wire to the solid orange and solid yellow wires on the high level inputs on the Boss equalizer. The easiest way to do this is to introduce a wire from the end of the red wire and run it to BOTH the solid orange and solid yellow wires. Once this is done, go back to the pair of red w/black stripe wires, and run a similar jumper wire to the orange w/black stripe and yellow w/black stripe wires. In doing this, you have broken the circuit of the sound system and introduced the Boss amplifier as a new component of your Stern pinball's sound system. Just think of your pinball machine as a car, and the equalizer as a car radio headunit; it is pretty much the exact same thing.
Now, we need to get power to the Boss equalizer. to do this, get your computer power supply and put it somewhere in the machine where the slide rails will not interfere with it. On your computer power supply's wiring, you'll need to locate a 4 pin connector that has a pair of yellow wires and a pair of black wires. These are 12V power wires - solid yellow being power and black being ground.
1. Strip a pair of these wires
2. Connect the red wire and the orange wire from the equalizer to the yellow wire of the computer power supply.
3. Connect the brown wire and black wire to the black wire of the computer power supply.
4. Plug the computer power supply to the service A/C outlet in the bottom right of your Stern machine and make sure the machine has power (you do not need to fire the machine up).
You should now see the equalizer lights (green) come on. Once you've verified this, unplug the power plug to your computer power supply for now.
Now, we need to run speaker wiring back to your Pyle speakers in the speaker panel. Get your extra speaker wiring (some should come with the Pyle speakers and is PERFECT for this part). Strip the solid green wire and the green w/black stripe wires, crimp the speaker wiring to each of these wires, and run the speaker wiring back to your Pyle speakers on the left side. There is no polarity, so either wire should be able to go to either speaker spade terminal. Do the same for the right Pyle speaker; I used the purple and purple w/black stripe wires. You are now done with the translite speakers. Fire your game up and make sure they are operating before moving onto the cabinet speaker (it's easier to correct something now then later when more stuff is hooked up).
Now for the cabinet speaker - get rid of the factory and introduce your new Pyramid speaker. The machine's wiring should be a yellow w/black stripe wire and a yellow w/white stripe wire. Introduce these wires to either the orange and orange w/black stripe wires OR the yellow and yellow w/black stripe wires. You only need one pair as you are only hooking up one speaker.
Get your second amplifier in place and hook up the power and ground using the other pair of yellow and black wires as you did for the first amplifier (you should have one remaining pair of solid yellow and solid black wires left ready for this).
Now, run speaker wires from the equalizer to the speaker as you did for the translite speakers.
**- IMPORTANT NOTE here -**: match the inputs with the outputs here. If you pick a "left" input, pick a "left" output. So if you use the orange and orange w/black stripe wires for your input (right side), MAKE SURE you use either the solid gray and gray w/black stripe wire pair or the solid purple and purple w/black stripe wire pair (both right side speaker outputs). If you go mixing left inputs with right outputs or vice versa, you'll get VERY MINIMAL sound, and you'll be very disappointed with the results. Trust me on that one.
For the external subwoofer, run speaker wiring from the subwoofer and you can simply alligator clip them to the spade terminals of the cabinet speaker, or you can connect the sub to the equalizer through the use of RCA cables. Both the sub and the equalizer will have the proper connectors; you just need to supply the RCA cables.
I can take pictures of all of this for anyone who needs them.
I uploaded a series of videos documenting this visually with my GoPro. There are a total of 3 of them.
If you have any questions about this setup, you can always PM me. I can answer questions about THIS setup. If you introduce other amps, I'll try to help - just please know this is the setup I use and am comfortable with answering questions.