Article 14

Bobby Nathan's

Keyboard Magazine "In The Studio"

Article # 14

Build Your Own Patch Bay

"If the console is heart of a studio, then the patch bay is truly the veins and arteries".

Let's start from the beginning. First Patch Bays aren't cheap! They call for good soldering skills and call for proper planning to arrange, but after you have one, you'll wonder how you've ever lived without one!

There are three basic types of Patch bays .. RCA, Phone and Bantam. The first RCA, is the least expensive. Most RCA bays are pre-made. That means no soldering ! There are RCA jacks on the front and on the rear too. You simply buy the appropriate interface cables ( between console and bay and your outboard gear and bay ) and hook it up. The downfall of the RCA type bay is that it is unbalanced and the RCA plug in nature is a hard plug to strain relief! This means that the plastic molded type of RCA patch cords you'll be using are going to break on you quite regularly. This is because they fit so snug. Then pulling on the RCA patch cord itself, not the by the connector, causes a break in contact at the molded plug's end. This can be avoided by grasping only the molded plug itself not the cable.

The Phone Jack bay uses 1/4" guitar type patch cords. This is handy for plugging keyboards directly into the bay. The strain relief type 1/4" phone cables are more rugged and last longer. They are also more expensive but, can be found more readily and in many more variations of length. There are some companies that make pre-wired 1/4" patch bays that terminate in either RCA or 1/4" phone jacks at the rear. Once again if you are not into soldiering this is the way to go! Phone jack bays can be ordered balanced ( tip, ring and sleeve ) to allow for longer cable runs. Generally they are 24 jacks to a row, 48 to a double row bay. They can also be ordered with the normaling option. Normaling allows certain patches in certain consoles to work better. For instance, most consoles have an "insert in/out" patch that shows up on the rear of the board. If you plug your snake into the in and out jacks and connect those in's and out's to a patch bay, the channel won't pass signal unless a patch cord is patched in the bay connecting the " in " to the " out ". Normaling makes the connection. The only catch is you have to wire it up. When a patch is patched into the return ( the "in" ) it breaks the normal and something else can be patched in.

The last type, Bantam is in my estimation the best. The Bantam bays fit the most jacks per row ( 48 or even 56 across ). A double row bay can hold then 96 or 112 patch points total. They work well but do require regular cleaning with the proper solvents and utensils. Pipe cleaners work well. Their immediate advantage over RCA's is that they come balanced. This means longer cable runs (snakes) can be used without picking up RF problems. They also have another advantage over RCA bays in that they can be purchased with or without normaling. Bantam bays are more expensive and are generally not found ready made, that is with rca plugs on the back. If you are not going to soldier one up yourself, you can probably find someone in your area that can do this work for you at of course an elaborate expense. Bantam patch cords are less money generally than 1/4" phone plug patch cables. They are available is various lengths with the 18" and 24" lengths being the most popular.

Now the fun part. After you've selected which type of bay you're going to use. Now the planning begins. One of the reason's we wanted a bay in the first place was to avoid going behind the console every time we wanted to plug something in or out. For stage, the best setup is to build a snake box that will sit near your keyboards. Belden or Connectronics multi conductor cable is what you want to use for this. If you have a console with 16 or 24 inputs then you are going to want a snake box with sixteen or twenty four inputs too. To switch things around during a show, in case you loose one of your consoles input modules, you are going to want to connect your snake box to the bay. In building your snake box, you may want the jacks to be all 1/4" or XLR cannon or each input to be both. If you are plugging a 1/4" unbalanced keyboard into a balanced input you will need to install direct box type balancing transformers inside the snake box. They are available from Whirlwind and are called 20k to 200 ohm Direct box transformers. Anyhow below is a sample diagram of how to arrange you patch bay.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 snake inputs o o o o o o o o o o o o o o o console mic inputs o o o o o o o o o o o o o o o tape machine returns o o o o o o o o o o o o o o o console line inputs o o o o o o o o o o o o o o o console buss outputs o o o o o o o o o o o o o o o tape machine inputs o o o o o o o o o o o o o o o

Now looking at the above diagram notice that the snake inputs could be wired normaled up to the consoles microphone inputs as could fit into one double row bay. The tape machine returns could be wired normaled to the consoles line inputs and would again take up one double row. The console's buss outputs normaled to the tape machine's inputs. Notice how the numbers all line up. Snake input #1 and console input #1 and etc.

Effects sends and effect inputs should also be arranged in the same area for speed and convenience. The same with effect outputs and console effect returns. The same goes for the 2 mix outputs and stereo two track recorder or stage power amps. In the tool area you will need a 15 watt soldering iron with a relatively small tip, a roll of 60/40 rosen core solder, a wire stripper, wire cutter, needle noise pliers and patience ! You will have to order enough wire and shrink rap ( plastic tubing that is used to dress the ends of wire ) and a heat shrink gun ( like a hair blower but much more powerful).

You will need the appropriate type and amount of Patch bays ( either RCA, Bantam or Phone), adequate number of connectors ( to connect the bay to all the jacks on the rear of your console and outboard gear ) and of course ample Patch cords. For wire, you can again use Connectronics multi-snake cable or equivalent. Connectronics wire is color coded. It follows standard resistor color code and a guide can obtained at a electronics supply store. Make shure it has two conductors and a shield (braided or bare wire used for the ground ). Before plugs are put on the console or outboard gear's end of the snake, the wire should be measured to the desired length and then dressed. To prevent possible shorting ( grounding ) out, the bare shield is dressed with 3/64 th clear shrink tubing. Shrink tubing comes in four foot lengths so cut it into 1 1/2" pieces ahead of time. Strip the wire an inch and a 1/2 at both ends of the snake." Put the shrink over the shield and carefully melt the shrink rap over the top of the heat shrink gun. Be extremely careful as the Heat Shrink gun can burn your skin off. Not too good for keyboard riffs. After you have dressed the shield put a piece of 3/16 th black shrink over the wire right where you've stripped it, covering the dressed shield about a 1/16 th of an inch. Now the end is dressed. For added neatness 3/32 th black shrink can be cut into 1/4" slivers and placed on the wire before soldiering it to the bay's connections. After each connection has been soldered to the bay the 3/32 th slivers can be shrunk over each wire where it meets the connector. When using the Heat Shrink gun be careful not to give the shrink tubing too much heat or it will crack or what's worse melt the wire!

Now for the soldering lesson. If you are not good with a soldering iron, two things will happen, You'll either get better or you'll waste your money. First to make a good solder connection it is important that the tip of your soldering iron is kept clean. An old sponge moistened makes an excellent cleaner. Next tinning all your wires in advance makes soldering faster. To do this, first touch the tip of the iron to the already twisted wire. Then touch the solder to the wire. Never put solder on the tip itself. When you see the soldier melting (flowing) down the bare wire you know it is well tinned. Remove the iron immediately. You do not want to melt the plastic off the wire. The connections to the bay's jacks should be tinned first too. Then when soldering the wires to the jacks connections, hold the iron on the jack's connector and place the wire in position. When the solder on the wire begins to melt, put a dab more solder on the connector and after it flows , hold the wire very steady and remove the iron quickly. In summing up, make a chart of the individual wires in each snake ( color codes to functions ). Also label each snake (i.e. Console mike inputs, Keyboard snake, etc. ) and before you start soldering, be sure you have the proper connections diagrammed out. Many times the top row of a bay has different pin outs than the bottom row. It's a real pain to unsolder all your hard work. Also take a break from the solder's lead fumes after every hour or so. If you're not use to them they can make you dopey. Write a hit song during your solder breaks. Many a hit was penned over hot lead !

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