I have promised (or threatened) more than once that I would address how to solder properly. And that is the subject of this installment of Sound Sanctuary. However, I have got to tell you all about an amazing outreach program I have had the pleasure to be involved with over the last few weeks. The organization is called WOW JAM or WOW (Winning Our World) International.
A Moment for WOW JAM…
WOW is a music-based Christian outreach raising the name of God worldwide. The center of the presentation is a self contained truck/stage. The truck rolls up and the stage unfolds, revealing a 16,000-watt, 12-box (six per side) QSC line array. Along with the array are some very powerful subs that add the low end to this quality sound system. Stephen Tavani heads up WOW International along with his wife Linda (formally Peaches of Peaches and Herb 1970s fame).
Stephen is a gifted preacher and, of course, Linda (Peaches) has a great singing voice. But what really impressed me about the WOW JAM presentation was that, along with the music, WOW serves food, fixes bikes, cuts hair, does makeovers, rocks babies, paint faces and nails, take pictures and give away groceries. They really connect with the needs of the local communities. I was with WOW at Villa Park in Pasadena, Skid Row Los Angeles and South Central L.A. The experience was awesome. If you hear of WOW JAM coming to your town, make sure to check them out or get involved. You won't be disappointed.
Now, Back to Soldering!
Okay, back to soldering properly. In the many years I have been in the sound biz, I have seen dozens of situations where an expensive, high tech sound system is taken down by one bad cable. Bad cables are simply bad for audio, and the only cure is to throw them away or fix them. That said, let me give you an obvious word of caution. Soldering irons are very hot and can severely burn your skin, not to mention burn a hole in your new jeans or shirt. So take it slow and be careful at all times.
There are a few different choices for soldering tools. I prefer a soldering station. You know, those tabletop units that feature a pencil-type tool with a temperature control. The purpose of the heat control is to be able to adjust temperature from one job to another. For example, XLR cable can be successfully soldered at 500 to 700 degrees, whereas a heavier speaker wire attached to a Speakon connector or ¼-inch jack can take 800 to 900 degrees. Incorrect solder temperatures can cause problems. Applying too much heat can damage plastic parts and wire insulation, while applying inadequate heat will cause prolonged waiting periods for solder to melt (reflow), resulting in a poor solder connection.
Whatever tool you choose to solder with, your main ingredient is still solder! The standard solder wire for audio repairs is 60/40 rosin core. The 60/40 refers to 60 percent tin and 40 percent lead. The rosin in the core of the solder wire is used for deoxidization (cleaning) of metals so they can be joined. The rosin performs this process quickly and ensures that the solder wicks (adheres) to both adjoining metals. I use solder wire that is 18 or 20 AWG (American wire gauge). This size of solder will melt quickly and flow properly under the right amount of heat.
Practice Makes Perfect
Now let's to turn up that heat and get to work. The terms "reflow" or "reflowing" describe heating solder until it is in a liquid state and using it to bind two separate pieces of metal or wire together. If you don't already know, soldering with good proficiency will take a certain amount of practice. That said, it is a good idea to practice on cable you don't necessarily need before you start soldering the main wires of your sound system.
Good solder joints start with good mechanical connections prior to reflowing solder over the connection. If you can crimp, or wrap a wire around a solder post, tab, or another wire, then do so with as much care and precision as possible. There is one very important exception to this approach: XLR cable ends have solder cups for their wire connections. Wire is placed in these cups and solder is reflowed over them. XLR or microphone cables take more abuse than other cables. This means that you may be repairing more of these cables than anything else. I like to tin my wires before any reflow.
Tinning Before Reflowing
Tinning is a process in which you melt a small amount of solder on the surfaces to be joined. When tinning, remove any excess insulation as well as any fraying wire strands. Bend the wire to the close-to-final shape of the solder connection. Add heat to the wire with your iron first, then touch the hot wire with the solder. The idea is that the surface of the wire will melt the solder, not the iron itself. This is the same rule with all solder joints. You do not melt solder on your iron but on the heated wire or joint.
That said, it is important to freshly tin the soldering iron tip. Wipe the hot tip of the iron clean (on a sponge, not your T-shirt) and apply a small amount of solder to the tip. This creates the heat transfer point. Refrain from melting an abundance of solder on the iron tip and sticking it onto the surfaces to be joined. Unless you avoid that, it will cause what's known as a cold joint and will not hold. Also, too much heat can damage electronic components and insulation and generally melt things you don't want to melt. With that in mind, once you reflow the solder, remove the iron quickly.
As you can see, good soldering will take practice but nothing beats the feeling of a perfect solder reflow – and turning lead into gold. Good luck!
