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--- building instructions ---

Note: Some pictures are from other kits that illustrate general construction techniques.

If your board does not have any pre-installed components, skip directly to Step 1--everything should be OK.

We found a last minute problem on some of the pcbs, and added some jumpers to correct this. We received feedback from a few people that those corrections weren't completed properly, so here are some things to check before starting:

There are two traces that should be cut: one on the back...

and one on the front. Double check with an ohm meter according to these pictures to make sure the traces are truly cut. If the resistance is low, (under 10k ohms), then go over the existing cuts with a knife until the connection is broken.

• Soldering Iron and Solder: A 15 Watt iron will may get the job done, but it'll be easier with a 25 or 35 Watt iron. The larger pot and switch connections can draw a lot of heat. We like small chisel or screw driver shaped tips (say 1/16th of an inch wide), but personal preference plays a big role. The goal is to use a tip that's about the same size as the pad you're soldering. This way you get you get as much surface area contact as possible (better for heat transfer) but are still small enough to avoid touching neighboring pads.

  For solder, we recommend .02 or .031" diameter, rosin cored flux, tin-lead solder, either 63/37 or 60/40, whatever's cheaper. See our soldering guide for explanations. Lead-free solder is a little bit harder to use since it "wets" metal somewhat slower and has a slighty higher melting point. If your kit has sat on the shelf for a while (a year), some steel wool or a pink eraser is useful to remove oxidation from the components and board before starting.

• Wire: This kit involves a decent amount of wiring, we recommend you use 22 to 28 gauge stranded wire because solid wire is less flexible and can break as wires shift around. Colored ribbon cable is very helpful. Some colored ribbon cable can be bought here.
• Needle Nose Pliers: Used to clinch or bend component leads, help remove components, and in this kit, remove metals stubs from the pots and also tighten nuts. (buy)
• Helping Hands: Two aligator clips on a heavy base that are useful for holding wires while you solder them.(buy)
• Flush Cutters: Used to trim leads close ("flush") to the board. (buy)
• Solder Sucker or Solder Wick: Used to remove solder. (buy)
• Clamp: A table top will be fine for most of the job, but a clamp can be handy, especially when removing components. (buy)
• Multimeter: To make sure voltages are OK before inserting chips, and also to debug later.
• Wire Strippers: (buy)
• Screwdriver: A large phillips for the case screws and an eyeglass phillips for the joystick screws. Some wrenches might also be helpful for mounting the jacks, pots and switches.

First, start with the resistors. Prebend the resistors beforehand using pliers or a resistor bending tool to keep from damaging the pcb while inserting them. Go in order of height, from shortest components to taller ones. This order lets you use the table to help hold things in place by resting the board upside-down while you solder them. It's convention to install resistors so their code can be read left to right in the same direction as the silk screen (tolerance band on the right).

1 resistor goes between the power LED and power, not on the pcb.

Use the list of names and values below to match each resistor value to the corresponding position on the pcb (R1, R4, etc).

• C9,C11,C12,C14: .1uF ceramic
• C1: 330pf
• C7, C8, C10, C13: 10uF electrolytic
• C2,C3,C4: .033uF
• U1: MC7805CTG
• U4: MC7905CTG
• U3: CEM3372 (filter)
• IC1,IC2,IC3: quad opamp TL084CN
• C6: 4.7uF electrolytic
• C5: 2.2uF electrolytic
• D1,D2: schottky diode, 1A
• R1-4,7-10,13-14,25,27,30-33,36-39,,42,44,45,47,48: 10k 1/4W resistor
• R17-19,22,96: 1k
• R21,23,26: 22k
• R20: 33k 1/4W
• R24: 47k
• R40,41,49,50,51: 510k
• R5,6,11,12,28,29,34,35,43,46: 5.1k
• R15,16: 68k
• R91-95: 100k linear pot
• (3) 1/4" jacks
• (9) 1/8" 3.5mm switching jack
• RX,RY: joystick
• dpdt switch for power
• D9: red LED
• (1) LED panel mount holder for 5mm LEDs
• pcb
• 18 pin DIP socket (for op amps)
• (3) 14 pin DIP socket (for filter chip)

• (2) 9V Battery holder (buy)
• (5) black knobs (buy)
• A silk-screened and pre-drilled case, with hardware and rubber feet (buy unfinished case)
• (8) 4-40 nuts (buy)
• (8) 4-40 screws (buy)
• (4) standoffs for the PCB (buy)
• (4) 2-56 x 7/16 screws (for joystick)
• (4) #2 nuts (washers may be included, also).

The below picture shows all the resistors' leads splayed out so that they hold in place. It's probably easier to only put a few in at a time. To keep components in place while you solder them, clinch (bend / splay) the leads outwards. On the IC, do this for two opposite corners. This is actually what automated machines do to keep chips in place while the boards are run over fountains of liquid solder (wave soldering).

Note: in this kit, solder the sockets, not the ICs themselves.

Trim the resistor leads with flush cutters after soldering them.

Now add the diodes and the disc (orange / flat) shaped capacitors. Orientation doesn't matter for the caps, but it does for the diodes. Match the stripe on the diode (white on black) with the stripe on the board.

Add the electrolytic caps (the cylindrical ones). For these caps, the polarity (which pin goes in which hole) matters. The square pads on the pcb indicate pin 1, and that can either be meant for the positive or negative lead on the cap. In this kit, the positive leads all go into pin 2, which is the round pad. On some of our other kits, it's the opposite. The longer lead is the positive lead on the cap.

Finish up with the transistors and ICs, being sure to align the notch on the end of the IC with pin 1 (the sqaure pin).

Tin the tip, or in other words, add a bit of solder to the tip, first. This small amount of solder forms a "heat bridge" to help conduct heat from the tip to the pad and component lead. When you first contact the parts with the iron tip, it's helpful to first place some solder in between the iron and components, then melt solder on the the side opposite from the iron tip. This ensures that the component is hot enough to bond to the solder, and also helps to spread out the solder as it will run towards the heat source.

On ICs, it's a good idea to solder every other pin (and then fill in the gaps) to reduce the risk of overheating the component.

Cut off the leads as you go with flush cutters. Watch out for flying leads; safety glass are actually not over-precatious for this, although we generally just hold the lead with fingers to keep it from flying off.

First break off the anti-rotation tab with pliers, then install like the following picture shows:

Install the LED holers from the outside, then press the LEDs into them from the inside until they snap in place. This can be surprisingly tricky. Try to keep the holder as far in as possible while pushing the LED through from the other side (this is hard because you'll be trying to get the LED to go past where you finger is pushing on the holder). Lots of wiggling will help more than lots of force. Sometimes you may have to bend out the holder legs a bit with a screw driver to loosen it up a bit.

The easiest way to do this is to rest the case face down on some blocks. Drop a nut into one of the corners and hold it in place with a drill bit or pencil. The corners of the joystick casing should keep the nut from rotating.

If small #2 washers came with your kit, place those in between the joystick and the case. This keeps the case from pinching the joystick's ball joint.

Start the screw by hand from the other side. Start all screws this way before tightening any one of them. Use pliers to hold the nuts if necessary for a final tighten.

Once you have all the components in place, we recommend pre-cutting and stripping a bunch of wires that are about 15" long. This may seem excessive, but it's very helpful to have some room to route wires. And, in case anything goes awry, there will be enough slack to cut off some of the wire. Small gauge (24+) colored wire is highly recommended along with some zip ties.

First loop the wire through and bend it to hold it in place, then heat the joint from one side and apply soder to the other. Again, it will help to put a bit of solder between the iron tip and connection to act as a heat bridge.

Before wiring, it's a good idea to tighten everything down to reduce the risk of breaking solder joints later.

Use the following connection diagram and the listing from above to wire each part. The grounds don't have to be connected exactly as shown, just make sure each ground pin (green line) is connected somehow.

Note the jumper wires at the bottom of the diagram between the 2nd and 3rd pins of K12, K2, K3, K7 and K9. If you like, you can replace these with potentiometers to provide attenuation.

A good place to start is the with the ground wire (green).

Finally solder wires to the battery holder, attach the standoffs to the pcb.

Use a small flat-head screwdriver to install the knobs on the front.

When you turn it on, have a multimeter handy to check some voltages. Pin 4 of the opamps should be V+ and pin 11 should be V-. It's a good idea to check this before installing any of the chips.

If the battery voltage is dropping quickly, there might be a short somewhere. Make sure no stray strands of wire are touching the case or other components.

Visit our VOS forum if you run into any trouble.

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