This article will show two possible builds: The generic build on the right uses a standard 125-B enclosure that is available from many sources. On the left is a "deluxe" build in the made-for-Small Bear Bare Box #1. That one uses a number of made-to-order parts and specific modular connectors to produce a result that is comparable to a manufactured product. The sloped design reduces greatly the risk of stomped pots, and it includes a battery door. The difficulty levels of both builds are about the same, and  complete kits are available to take you either way.

• What transistors do these builds use? Can I use my own?

If you bought my breadboard kit, it included two NPN silicon devices that will work with the resistor values shown here with little or no trimming. Absolutely, you can use your own; numerous types will work and they are readily available and cheap. Breadboard First so that you know you'll be happy with the finished build!

• What's the big deal about using germanium? What are the issues?

The tone is different--not necessarily better, but different. Beyond that, it's harder to find germanium devices that hit usable gains--especially NPN types--so they are much more expensive. There's more information on this subject in my Fuzz Face FAQ. Again, before you start this build, make sure that you have suitable devices and that you have tried them on your breadboard before proceeding.

• I have a pair of known-good germanium devices, but they are PNP. Can I use them?

  Absolutely. However, all polarities in the circuit shown here must be reversed--power, protection diode and electrolytic capacitors. There is a layout drawing at the end of this tutorial that shows a layout for PNP/positive-ground.

   

• What about wiring PNP/negative-ground or using a charge-pump conversion circuit?

  The first is not recommended because of sometimes intractable problems with oscillation. I chose not to use charge pumps in these builds to keep them as simple as possible.

Breadboard To Box - What Is Involved?

If you followed the breadboard build to a basic Fuzz Face, you have a working circuit, complete from input to output like Figure 1.

Clearly, a number of elements need to be added to make this into a buildable design for a finished pedal. The most important is bypass switching, to allow the effect to be foot-switched in and out. There are numerous schemes for doing this, and I chose one that's known to work well and uses components that can be found almost anywhere.

3PDT True-Bypass Switching With In-Use LED Driver - How It Works

Here's a bottom view of a typical 3PDT (Three-pole, Double-throw) footswitch. It has nine contacts, and they work as shown in the schem in Figure 2. Push/release once and the moving contacts (2, 5 and 8) connect to #3, #6 and #9. Push/release again and they go back. We call this a "latching" or "alternate-action" switch, because the contacts remain in their new positions when you release the switch.

In Figure 3, the effect is bypassed. The guitar input goes from the moving contact, pin 2, through stationary contacts pin 1 and pin 4 (which are connected with a jumper) to moving contact pin 5 and then to the output jack When the switch is stomped, the input jack sees the effect input through pin 3, and the output jack sees the tone control through pin 6. Two contacts of the third pole switch the LED on and off. OK so far? If you still have the circuit on your breadboard and want to set up the bypass to see/hear it work, by all means do so.

Answer to FAQs:

• There are other ways to wire a stomp switch, with and without an in-use LED. They will all work, though some may be more suitable than others in a particular design situation. If you want more information, check the Beginner FAQ or other on-line sources.

  
  

• The 2.2 Meg resistor at the input is added to prevent switching "pop" noise.

Power - Internal and External

While we were on the breadboard, we switched power off by disconnecting the battery. That won't work in a pedal, so we have to make some arrangements. And there are several issues:

• We want a DC power jack, and we want the battery to be cut off when an external power supply is plugged in.





• We want the circuit to be protected from reverse connection of power.





• We want battery power to be cut off when the guitar plug is removed from the input jack.

Most modern pedals accomplish all of this in the same ways. External power comes in through a jack like the one of the ones in Fig. 4. These styles are designed to be mounted on the panel of an enclosure, while others mount on a circuit board. They all work similarly, as shown in the small schematic (Fig. 5). Contact #1 connects to the shell of the power plug, which will be positive in the typical negative-ground pedal design. Contact #3 forms a normally-closed switch with contact #1; it shorts to #1 until a power plug is inserted. Contact #2 is the center pin, which will be ground in this configuration.

Diode D1 takes care of reverse polarity protection; it will block current flow if the battery or power supply is connected incorrectly.

Here is the whole, buildable schem, including all of the support circuitry.

FAQ: Which Material? Pad-Per-Hole vs. Veroboard

You will see many designs laid out on stripboard, also called Veroboard, or just Vero (Fig. 7). While I stock it because it's very popular, I don't recommend it for first builds. It's very convenient to use, but it does not force you to follow the logic of a schematic and wire point-to-point.  To my mind, that's an essential skill that a beginner needs to develop.

I recommend perforated circuit board, or perfboard as it is commonly called (Fig. 8).  Each hole on the bottom of the board is surrounded by a tinned copper pad to which solder can bond. This type of stock is called, appropriately, pad-per-hole perfboard. Component leads are inserted through the holes and soldered in place on the opposite side. Connections are made with short lengths of bare wire.

The piece shown in figure 8 is 60 mm x 60 mm, sized exactly for the Bare Box (my SKU 0355), but any similar material with holes on .100" centers will also work.

A smaller perfboard (SKU 0356) sized exactly for the 125-B enclosure is available for the generic build.

Before you begin creating the board, make sure that you have all the tools required. You'll need a few basics:

• 25- to 35-watt soldering iron, rosin-core solder and cleaning sponge
• Small screwdriver(s)
• Small chain-nose pliers and side-cutters
• Small locking-grip ("Vise-grip") plier
• X-acto or similar knife
• Self-locking tweezers or other "third hand"
• Small alligator clip
• Colored pencil or "Hi-liter" felt-tip marker
• Some small round and flat files
• A pointed steel "pick" or scratch awl
• De-soldering braid

If you buy one of my kits, case is pre-drilled. If you are rolling-your-own, be prepared to borrow a drill if you don't have one.

For finishing the case you'll need:

These tools, and many others, are available in my Stock List.

For the generic build, the board needs to be cut to 14 rows by 23 columns and two mounting holes must be added. If you don't have a Dremel tool, use a knife and a steel rule to score the board in the 15th row all the way across (Figure 10). Score a dozen or so times in order to deepen the line. If you have a vise or have access to one, clamp the piece in the jaws on the score line. Wedging the piece in a door frame will also work (Figure 11). Apply steady pressure on the edge until you feel the material snap. Borrow a drill if necessary to create two new 1/8" mounting holes (Figure 12).

If you have a Dremel tool and an abrasive cutoff wheel, this combination is by far the easiest way to work perfboard. However, if you go this route, be aware that the dust that the operation throws off contains fiberglass. WEAR GLOVES, GOGGLES AND A FACE MASK!

If you are building in the Bare Box, continue in the next section. For the generic build continue below.

Below is the board layout and a parts list. You are seeing the board in "X-Ray" view; the red lines are connections that we will make with bare wire on the bottom of the board. Print a copy of this drawing and the schematic so that you can mark off connections with a highlighter as you work. This is one of my time-tested methods for catching mistakes before they cost me time and frustration.

We are ready to populate ("stuff") the board. While components can be added in any order, I'm going to suggest that you start by installing the Molex headers for power, signals, switching and the pots. With those in place, you'll have good physical reference points for installing all of the other parts. Please note that I don't cover basic soldering techniques in this article; you may want to check a reference and do some practicing if this is your first build.

Find a two-pin horizontal Molex header (Fig. 21). Install with its pins in indexes K-6 and L-6, use self-locking tweezers to hold it and solder in place (Fig. 22).

In the same way, locate, install and solder in place the other horizontal Molex headers: three-pin for the input, two-pin for the output and six-pin for the stomp switch. Follow with the two three-pin vertical headers for the potentiometers (Fig. 23, Fig. 24). Align the vertical headers as shown in the pic with their chamfered sides to the left.

Now for the plumbing! With all the components in place, we begin to make connections between them with short lengths of bare tinned wire. First we'll do a long one: from the negative power input to the Ring of the input jack J2. Put a very short right-angle bend in the end of a length of bare wire, and insert this into the hole at index J-6. Use the locking tweezers to hold it in place and solder at J-6/K-6 (Fig. 32). Now use a chain-nose plier to put two right-angle bends in the wire, one in row 5 and one upward in column I. Make this as sharp as you can. "Tack" the run as shown at J-5 and I-2 (Fig. 33).

Bend leftward at I-1, tack at D-1 and bend downward in column C.  Bend clear of the mounting hole to get over to column A Bend downward, tack at A-9, right-angle bend again at A-10 and tack at C-10. Do a 45 degree bend at D-10 and end at G-12 (Fig.34).

Make the connection between L-5, the positive power input, and N-4, the positive side of diode D1. Slip the end of a short length of bare wire into hole L-6 and hold down with soldering tweezers. Solder at L-5/L-6, clip at N-5 and finish soldering at N-4/N-5 (Fig. 36, Fig. 37).

Continue the run by butting a length of wire against D-5 and soldering. Then create a sharp right-angle bend in column B. Tack at B-9 and bend again (Fig. 40).

Bend downward in column H, tack at H-14 and bend again in row 15. Finish this part of the run at the Emitter of Q-1, index G-19. Back up and create a solder "bridge" between the ground run and the sleeve contact of the header at index G-13 (Fig. 42).

Continue by butting a length of wire to index F-17 and soldering. Tack as needed to make the bends around capacitor C2, stop at resistor R1 and solder at index L-22 (Fig. 43)

Make the connection between the positive side of capacitor C1 at index F-2 and resistor R4 at index H-6 (Fig. 45) This access to the positive side of the capacitor from the top of the board, and I can show you a troubleshooting technique.

I like to use the capacitance scale found on many multimeters to test continuity where a capacitor contacts a run on the board. Look at the layout (Fig. 20) for a second: The positive side of C1 contacts index H-6, and its negative side is grounded. So we should see the value of the capacitor between index H-6 and any point on the ground bus, right? And so we do, as in figure 46. (The capacitor is nominally 100 mf., but tolerance is typically 20%, so this is in range). Used consistently, this technique will smoke out numerous joints that are not quite connected.

If you are with me so far, you have the basics of the technique. Here is a table of the rest of the connections in the order I did them, with some notes where appropriate. With a highlighter, mark off connections on the layout as you make them.

If you bought the breadboard kit and are re-using parts, unsolder the connecting wires from the potentiometer terminals. I will presume here that you are using my modular approach to making the connections, so find six terminated leads and two male three-pin Molex housings (Fig. 47). Reserve the red and black leads for power. Other than that, it's your choice for which color goes where.

Install each lead into its hole in the housing. The terminal has a flange on one side, and you will feel it click into place when it is fully inserted (Fig. 48). Cut the leads down to about 2", strip, and solder as shown to create the potentiometer assemblies shown in figure 49. Take special care to get each pot on the proper side and the terminal assignments correct.

In the same way that you created the connectors for the pots, install black and red leads to set up a connector for power (Fig. 50).

The Bare Box #1 enclosure is tooled to be friendly to shrouded jacks like those used in many "name" pedals. These have a chamfer (bevel) on the sleeve pin edge, which is helpful for identifying the contacts. Start by locating the sleeve contact of the input jack and soldering the black center lead of the plug to this contact. The sleeve contact is the one on the beveled edge (“chamfer”) of the jack. For ease of assembly later, it’s best if the lead enters from the bottom of the contact and is bent at right-angles as shown before soldering (Fig. 52).

Position the stomp switch with its terminals parallel to you as shown in the left-hand pic. Start the wiring by connecting the two terminals at the top left with a very short piece of bare wire, and then solder. When making the solder terminations to the switch, take care to route and dress the leads as shown; it’s important to being able to position them in the case later. The right-hand pic is annotated to show which termination goes to which contact (Fig. 54).

Initial Testing

Are you ready to test your work?  Plug in pots, jacks and stomp switch as shown in figure 55. Set both controls to their mid-points. Connect your guitar and an amplifier and connect a battery to the power leads. If you don't get fuzz, click the stomp switch. Got fuzz? CONGRATULATIONS!

If your build doesn't work yet, don't be too discouraged. Take a shower and grab a bite, since we know that you haven't done either one since you started this thing; troubleshooting requires a clear head and normal blood-sugar level. The first rule to keep in mind is that projects like this are all-or-nothing. If EVERYTHING is correct, the build works; if ONE thing is wrong, it doesn't. But you have something going for you: I built from the drawings shown here, and you can rely on them. Use them as your bible, and you'll find out what's wrong.

To start troubleshooting, make clean copies of both the schematic and the layout drawing. Use a highlighter to mark off connections as you check them. Go over the off-board connections first. If those look good, you have to verify the interconnections. Use the continuity setting of your multimeter to make sure that you actually have a connection between every point in the layout that is supposed to be connected, and that nothing is shorted. Found a bug? Time to do repairs.

You can also use the low-voltage scale of your meter to sniff out problems. With  your guitar plugged in (necessary so that the battery circuit is complete), hang the negative lead on the sleeve of the input jack. These were the measured voltages in the build shown:

 

	Collector	Base	Emitter
Q1	1.56	.65	0
Q2	4.45	1.56	.92

YMMV depending on biasing and transistor gains, but any serious differences are a sure indication that something is not right.

Once everything works, you can add the in-use LED and then proceed to the section on finishing the enclosure.

An LED is a diode, and so is polarized. By convention, they are supplied with the negative lead shorter than the positive. Insulate the leads using short pieces of spaghetti tubing, and then bend the ends away from each other (Fig. 56).

Solder the leads to the pads on the underside of the board. Positive goes to T-2 (join to resistor R8) and negative to U-4 (Fig. 57).

Before you go further, re-assemble your test setup and make sure that the LED works properly. If it does, the board is finished.

Mount the input and output jacks, dressing the leads as shown to keep the plugs out of the way of the stomp switch (Fig. 61).

Mount the stomp switch, being sure to orient it so that the plug assembly is on the right. The battery snap leads go between the jacks and around the stomp switch (Fig. 62).

Move the plugs aside enough to ease the board into place (Fig. 63).

Plug in all of the connectors. Maneuver the LED into its mounting hole and set the board down on its standoffs. Install one of the round-head screws to hold the board down temporarily. Connect your gear and a battery (Fig. 64).

Test the pedal. If something does not work, first make sure that all of the plugs are fully inserted and that none of the pins on the wires have worked loose. It's also possible that a connection broke during assembly or something is shorting inside. You may have to disassemble and go back to the troubleshooting section above.

Once everything works, finish securing the board. The threaded studs secure the side of the board that is next to the battery, and two of the screws that secure the lid will screw into them. To complete the job:

• Tighten the hardware on the controls and jacks
• Secure the lid
• Stuff a small piece of foam padding over the battery
• Install the battery cover
• Install knobs
• Install rubber feet

The board has room for bias trimpot R9, and it is shown in this build to indicate where it goes (Fig. 70). It is Not needed if you know the correct value for resistor R5 from having tweaked the bias on the breadboard.

When planning a board layout for manufacture as a printed circuit board, jumpers are sometimes a way to avoid the expense of a double-sided PCB. The jumper on the component side is shown as a thin blue line in the layout drawing. While jumpers are often bare wire, I used insulated here to avoid any chance of a short to the pin of diode D1. Cut a piece of wire to span eight holes, install in indexes F-2 through M-2 and solder in place (Fig. 72).

On the bottom side, butt a short length of bare wire up to the end of the jumper at index F-2 and solder (Fig. 73). With the chain-nose plier, create a sharp right-angle bend at index D-2. (I'll show you later when we do terminations how to make the connection to the potentiometer at D-1.) "Tack" the run with a dab of solder at index D-2, and bend again at index D-3. Bend downward in column A. Hold the run in place with the tweezers and add solder to connect indices A-9 through D-9 (Fig. 74).

Now you can do a continuity test from the terminal at index M-1 back to one side of R1 and the Emitter of Q-1 (Fig. 80). As you make connections, mark them off with a highlighter (Fig. 81).

Add another flea clip at index O-1. Insert a short length of bare wire in its hole and solder. This will allow you create solder bridges to index M-2 and the negative sides of capacitors C1 and C4 (Fig. 82).

Now butt a short length of wire to resistor R8 at index Q-5 and solder. Make a right-angle bend at N-5, tack there and make a right-angle bend at N-6. Cut at index M-6 and solder to bridge the connections to the + side of capacitor C1, resistors R3 and R4 and the negative (bar) side of diode D1 (Fig. 83).

If your multimeter has a capacitance scale (as many do), it's possible to test continuity through a section that contains a capacitor.

You can see in the layout where we have made the connection between the + side of C1,  resistors R3 and R4 and the negative (bar) side of diode D1. We have also made the connection between the negative side of C1 and the ground bus. So it would make sense that if we measure capacitance from the negative (bar) side of D1 to any point on the ground bus, I should see about 100 mf. (Fig. 84) I see 86.8 here, and that's within the normal 20% tolerance for an electrolytic, so I'm good. Use this technique wherever convenient to help ensure correct wiring!

• Insert a terminal at index C-3. A small piece of bare wire in the hole helps to make the solder bridges to C2 + and resistor R1.
• Butt a short length of bare wire up to index E-10. Solder her and at index E-6, the negative side of capacitor C2.
• Put a very short right-angle bend in the end of a length of bare wire and insert this in the hole at index E-11. Make the solder bridge to index E-10.  Right-angle bend in column C, bend again in row 14 and solder at index G-14. This is a good place to stop and test continuity and capacitance.
• The run from index F-9, Collector of Q-1 to the Base of Q-2 at index U-6 is fairly long, and you can do it in sections if it's easier for you.  Be sure that you pick up one side of resistor R-3 and test continuity at all points.
• Add snubbing capacitors CX1 and CX2 if you are using them.
• Insert a terminal at index D-1 and solder to index D-2.
• Insert a terminal at index H-1 and make the connection to one side of capacitor C3 at index H-8.
• Butt a short length of bare wire to index M-9 and solder. Right-angle bend in row 11 and stop the run at index H-11. Solder bridge to connect to capacitor C3 and resistor R5.
• Insert a terminal at index J-1 and make the connection to diode D-1.
• Insert a terminal at index Q-1 and make the connection to the positive side of capacitor C4.
• Insert a terminal at index S-1 and bend downward and over to column W. Make the connections to the Emitter of Q2 and resistor R6.
• If you are using trimpot R9, wire it in now. Otherwise, connect the Collector of Q2 directly to resistor R5.

The board is wired (Fig. 85, Fig. 86) and we can prepare the enclosure to connect to off-board components.

• With a good, sharp scissor, cut out the top template.
• Attach a couple of pieces of double-sided clear or masking tape to the box, and carefully center the template to the cover.
• In the same way, attach the templates for the sides, being careful to get the holes for the jacks in the correct locations to the right and left of the switch.
• Use a scribe or scratch-awl to put a small dent at the center mark of the hole for the stomp switch (Fig. 89).
• If you use standard twist drills, bore a 1/8" pilot hole, enlarge it with a ¼" drill, and then use a tapered reamer to slowly bring the hole to its final size.
• Follow the same procedure for the other three holes on the top, and then the holes on the sides.
• De-burr all of the holes with a small, round file. Remove all of the templates and tape, and you should have the result shown (Fig. 90).

Note: Many people like using a step drill (the common trade name is Unibit) rather than separate drills, because it does a quick, clean job of boring any size hole from 1/8" to 1/2" (Fig. 91).

BTW/FYI: All the finishing methods I am familiar with begin with sanding to produce a smooth finish that will be friendly to paint, powder-coating and/or decals. I like to wet-sand starting with 220 grit Carborundum paper, and I use progressively finer grits up to 600 to get a smooth finish. I got the "gun-metal" finish in the initial photo by sanding to 2000 grit and then buffing with aluminum wheel polish (auto supply store).

First job is to mark the areas in the enclosure that need to be prepped. Set the LED in place temporarily at indexes T-3 and T-4 and lower the board into place (Fig. 94). The LED should be exactly vertical its holes. Now mark the locations of the mounting holes with a pick or scribe (Fig. 95). This indicates the areas where the surface of the box will need to be cleaned.

Screw the studs to the board (finger-tight only) and prep them the same way that you did the box--roughen and clean up with acetone (Fig. 97).

Again place the LED temporarily and set the board in place. Take care not to touch any of the surfaces you prepped (Fig. 98).

Before mounting the LED, install a push-in terminal at index S-3. If it is oriented as shown, the LED lead will fit into the hole in the terminal--makes for easier soldering. Prepare the LED for mounting by cutting two 3/8"-long pieces of vinyl tubing (saved scraps from insulated wire work for this) and sliding on to the leads (Fig. 101). The shorter lead is negative. Using the chain-nose plier, bend the leads at right-angles to each other (Fig. 102). Cut down the ends and solder in place on the bottom of the board, being careful to observe polarity (Fig. 103). When you assemble now, the LED will drop into its hole.

• Wire from the Ring contact of the stereo jack to the center-pin contact of the power jack. The center-pin also gets the negative lead of the battery snap. The positive battery snap lead goes to the switched contact, #3.
• Create a ground run that connects the sleeve contacts of the jacks. The sleeve of the stereo jack gets a connection that will terminate on the board later. The sleeve of the mono jack gets a connection that will terminate on the stomp switch later.
• The board can be installed.
• Wire the stomp switch: Solder a jumper between contact #1 and contact #4. Use different colors of wire to make tracing easier.

Install the fuzz potentiometer in the same way.  Make the short connection to the power jack from the + power input of the board. Refer to the layout drawing and figure 109 to make sure that you have connected everything.

To complete the job:

• Tighten the hardware on the controls and jacks
• Secure the lid
• Stuff a small piece of foam padding over the battery
• Install the battery cover
• Install knobs
• Install rubber feet

The first rule to keep in mind is that projects like this are all-or-nothing. If EVERYTHING is correct, the build works; if ONE thing is wrong, it doesn't. But you have something going for you: I built from the drawings shown here, and you can rely on them. Use them as your bible, and you'll find out what's wrong.

To start troubleshooting, make clean copies of both the schematic and the layout drawing. Use a highlighter to mark off connections as you check them. Go over the off-board connections first and verify that the connections to power, jacks and switch are correct. If those look good, you have to verify the interconnections. Very Carefully, disassemble the pedal and lift the board and controls out of the enclosure. Use the continuity setting of your multimeter to make sure that you actually have a connection between every point in the layout that is supposed to be connected, and that nothing is shorted. Found a bug? Time to do repairs.

You can also use the low-voltage scale of your meter to sniff out problems. With  your guitar plugged in (necessary so that the battery circuit is complete), hang the negative lead on the sleeve of the input jack. You should see roughly the following voltages on Q1: Collector 1.56 volts, Base .65  volts, Emitter 0 volts. Q2 Collector should be  4.5 volts, may differ if you have a trimpot in there. Q2 Base will be same as Collector of Q1, Emitter typically .9 volts or so. If any of your readings are off these by more than 10%, you probably have a wiring error.