Preparing a ribbon cable

In the past, I’ve done several bends where each bend gets a wire to the pin. Instead, I’m going to attach a ribbon cable to each side of the sound chip. Conveniently, ribbon cables are available for cheap – I’m using a cable for a floppy drive.

First, cut off the connector. Then, count out twice as many wires as you have pins (I have 12 pins per side, so I’ll be using 24 strands of the cable) and tear off the extra. It should tear easily.

Next, strip the odd-numbered wires (counting the red-marked wire as 1) and cut the even-numbered wires shorter. We won’t be using the even-numbered wires; they’re just there to act as a spacer. Don’t strip off too much insulator; you only need a couple millimeters of bare wire to solder a joint and keeping it short will reduce the chance of (unwanted) short circuits.

Now the cable should line up with the chip, with one bare wire for each pin. Solder each wire to a pin, starting with the wire on each end. Doing them in this order will help keep the entire ribbon aligned as you work.

Do the same for the other row of pins on the chip.

It’s quite likely you’ll be attaching wires to pins you don’t intend to bend with, or maybe aren’t even used by the chip. Attach them anyway, as it will strengthen the overall connection. Later, you can add a blob of hot glue to strengthen it further and reduce the chances of a short.

At this point, it’s a good idea to re-checked the bends you found earlier, to ensure that your soldering job was good. It’s much easier to do this now than try to find where something went wrong later.

Connecting the breadboard

For a breadboard, I’ll be using a perforated circuit board with copper pads around the holes. These are fairly easy to use and cheap. For a good tutorial on building circuits on a perfboard, check out “Soldering a Perf Board”.

To connect the ribbon to the perfboard, strip or cut the same wires you stripped and cut on the other end of the cable. Twist the bare wire and tin it (put a tiny bit of solder on it to hold it together) and then insert it through the bare side of the board. You may need to separate the wires a bit more on this side to get all of the wires to fit. A little solder holds it in place.

A view of the perfboard and ribbon cable from below.

Adding switches/knobs/etc

Now I’m going to add a switch to control a bend I found earlier. Pins 16 and 17, when shorted, create a wonderfully crunchy overdrive effect.

Here, I’m taking a double-strand of speaker wire, and running the ends into the holes in the perfboard, next to the wires coming from pins 16 and 17.

On the copper side of the board, I bent each wire over and soldered it to the corresponding wire from the chip. Here’s one wire finished.

Then I soldered the wires to a toggle switch.

Since I might have 50-something switches, it’s a good idea to label them.