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  • Build Your Own Useful Adapter Boxes

    By Anderton |

    Build Your Own Useful Adapter Boxes

    The Only Way You'll Get These Boxes: Build 'Em Yourself!


    by Craig Anderton




    You won't find any of these adapter boxes at Radio Shack or your local music store, but they're incredibly useful. The only catch: You're going to have to build them yourself. But don't panic! The process is simple, and doesn't take much time (or effort) at all. You do need to know how to solder; but if you don't know how, commune a bit with Google and the internet, and all will be revealed—there's some good info at the Circuit Technology Center site, but there are plenty of other options.


    You'll need some tools, but you may have some of them already.

    • Variable speed electric drill with a selection of bits (1/16", 1/8", 1/4", and 3/8" are particularly important). When drilling a metal box, you'll need a center punch to create a small indentation prior to drilling. With a plastic box, unless you can find some bits for drilling plastics, begin with a 1/16" hole, then enlarge slowly by using ever-larger drill bits.
    • Vise grips, crescent wrench, and/or nut driver for tightening nuts on jacks and switches.
    • Small needlenose pliers for bending and working with wire and component leads.
    • Diagonal cutters for cutting wire.
    • Wire stripper for removing insulation from hookup wire.
    • An assortment of screwdrivers, including Phillips head and jeweler's types as well as regular flat types.
    • A small vise to hold parts for soldering.
    • 60 watt, small-tipped soldering pencil or (for those who like to go first class) a temperature-controlled soldering station. Wear eye protection while soldering; sometimes the rosin can spit out. Also, solder in a well-ventilated area.
    • 60/40 rosin-core "multicore" solder intended specifically for electronics work. Never use acid core solder! It's for plumbing.
    • Hookup wire; #22 or #24 gauge stranded works fine.
    • A small metal or plastic box in which you can mount the parts. Hey, some people use coffee cans...whatever works.


    So now that you have your tools, what can you build? Here are a few quick examples.






    Let's start with a box that switches a main input and output between two different effects or other devices (Fig. 1).




    Fig. 1: This photo shows the front and back of the A-B switch box.


    Now take a look at the schematic (Fig. 2).




    Fig. 2: A-B Box Schematic.


    All you need are six jacks, and one switch; S1 is called a "double pole, double throw" switch, because it has two "poles" that can switch between two different positions. For example, this box is ideal for switching between two mono effects boxes. However, if you ignore the labels, you can do some other tricks as well, like switch a power amp between two different sets of speakers. Patch the "Main Input" jack to your amp's left output, and the "Main Output" jack to your amp's right output. Connect the left channel from one set of speakers to "A Input," and the right channel from the same set of speakers to "A Output." Similarly, connect the left channel from the other set of speakers to "B Input," and the right channel from the same set of speakers to "B Output." Now you can switch between the two speaker systems.


    You can also use the A-B Switch Box to add true bypass to an effect—just patch a standard cable from "B Input" to "B Output," as this provides a bypass path whenever you switch to the "B" position.





    The stereo/mono breakout box (Fig. 3) provides an easy way to get mono gear to relate to gear with stereo insert jacks, or break out a stereo input or output to two mono connections.




    Fig. 3: Break out a stereo jack to two separate connections with this breakout box.


    Wire one mono jack hot lead to the stereo jack tip connection, the other mono jack hot lead to the stereo jack ring connection, then connect all the grounds together. To use the box with stereo (TRS) insert jacks, patch a stereo cord between a device's insert jack and the breakout box's stereo jack, then patch the mono jacks to your signal processor's in and out connections. If you don't get the tip and ring connections right the first time, reverse them and you should get signal.






    Fig. 4 shows another real simple, but invaluable, box.




    Fig. 4: Do you have two cables with plugs that don't get along? Here's the answer.


    The Universal Adapter Box simply has a bunch of jacks wired together: Stereo phone jack, two RCA phono jacks, stereo minijack, and two 1/4" phone jacks. As one example of an application, this is really useful for laptops. Run a cable with two mini plugs between the computer's audio out and the stereo minijack, and you now have a breakout box: Use the stereo jack for headphones, or use the two RCA or 1/4" phone jacks to feed a stereo system or mixer.


    These projects can take less than an hour if you don't care too much about looks. And if winter is approaching, don’t forget that a warm soldering iron will help heat up your room!  -HC-






     Craig Anderton is Editorial Director of Harmony Central. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.


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