Monte Allums Mods - Individual Pedal Mods









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Pedal Modding





Pedal Modding

In the Beginning

Several years ago around 2003 I decided to get into pedal modding. I have never been happy with the stock sounds of my pedals and the mods that were available on the Internet weren’t that good, in my opinion. We all have certain sounds we hear in our heads. These sounds are the tones we work to achieve with our rigs. But somehow these sounds are always elusive. We can never seem to satisfy ourselves. This is both a blessing and a curse. It’s a blessing because it gives us purpose, drive and keeps us on our toes. It’s a curse because the search for tone never ends, and can get expensive. As guitarists, we are never satisfied. We search for that ever-elusive Holy Grail of Tone. I like to say, “achieving good tone is a journey, not a destination”. To be honest, at this point in my musical career I am pretty happy with my tone. Pedal modding has gotten me closer to that elusive Holy Grail of Tone. And it can do the same for you.

Modding pedals have taken the control out of the manufacturers hands and back into mine. I’ve learned through trial and error just how to shape a pedals tone by changing a few components here and there. And the best part is, it’s fun! Once you have successfully modded a pedal there’s a sense of accomplishment and self-satisfaction you feel. Pedal modding is not hard and with the right tools and a little direction you’ll be up and going in no time.


Tools Needed

Soldering Gun – I suggest a 15 watt pencil head soldering gun. Amazon sells them for cheap. Make sure you buy a holding unit also. I like the ones that have a place for a pad. The pad is for dampening with water and cleaning the gun tip. Solder and flux can get caked on the end and the pad helps loosen the debris. IMPORTANT: Do not overheat the PCB. Doing so can cause the traces to separate from the PCB.

Solder – I use one kind. It’s 60/40 Resin Core and is perfect for pedal modding. I know there are some that won’t use anything but silver solder. I’m not one of them. First of all, silver solder is expensive and in my opinion is not worth what small minute benefit you may gain from its use. But, you be the judge, it’s your money.

Desoldering Wick Braid – Desoldering braid is essential. It’s used to remove the existing solder from the components you are modding. Don’t attempt any mod without it. It makes soldering much easier and neater. It’s essential to soak up all the old solder before changing a component. Not doing so can damage the traces. If solder remains when you remove the component you could pull the trace from the PCB. This is a good way to ruin your pedal. Make sure all the existing solder has been sucked up by the desoldering braid before removing the old component. If solder remains you can damage the trace pad or PCB. Never force a component loose. When all the solder has been removed the component will be easy to remove.

Solder Sucker – These offer an alternative to removing the old solder from components to be removed for modding. And they do an excellent job. In many ways it's a better alternative to using soldering braid.

Small Wire Cutters – These are used to trim the excess wire from capacitors, resistors, diodes, etc.

Needle Nose Pliers – These come in handy when getting into hard to reach places and when removing desoldered parts.

Reading Glasses - +1.75 to +4.50 Reading glasses are a must for us over 40 crowd. I do have 20/20 vision but my eyes don’t fare as well when reading or working on pedals.

Small Screwdriver Set – You see these kits everywhere. They come in a small case and usually contain 5 or 6 small Phillips and flat head screwdrivers. I use these to pry the old components off the PCB.

Regular Size Phillips Head Screwdriver – Most pedals use Phillips head screws.

Scissors – I use scissors to trim away the covering on small gauge wire. If you mod long enough you’ll have a wire or two come loose from the PCB. Usually the wire will need to be trimmed back and reattached. Scissors are great for trimming the plastic away from the wire.

Small Felt Tip Sharpie – For marking the solder joints on bottom of the PCB. This makes identifying the solder joints of the target component you are modding easier.

Patience – Don’t get in a hurry. I know it’s tempting - you want to finish quickly and try out your new pedal. Getting in a hurry is one of the reasons people have problems when modding their pedals. Always check the pedal after each mod. This way if there is a problem you’ll know exactly where it is. I get e-mails constantly from people asking for help after they have performed mods without testing between each mod. There’s no way I can help them at this point. The problem could be with the first component mod or the last and all points in between. Performing mods without testing the pedal after each component change is a recipe for a dead pedal and hours of trouble-shooting.

Light Source – A good light source is essential. Amazon sells a very handy LED light that attaches to the bill of a cap. It’s essential to have a good light source when working on these small components. This LED light focuses light right on the area I’m modding making identifying the components simple and easy.

Tackle Box – These are perfect for storing tools and mod components such as capacitors, resistors, diodes and opamp chips. I picked up the ones I use at Amazon. The sectioned compartments are perfect for organizing the different components and tools.


Pedal Mod Components and What They Affect

IMPORTANT: Never, under any circumstances, perform mods to a pedal that is attached to an AC Adapter. In fact, I recommend installing a battery while performing mods. This way you don’t have to worry about plugging in the AC Adapter to check the pedal after each mod. Pedal mods should be performed by persons 18 years of age or older, or accompanied by someone 18 years or older. Soldering guns can cause serious injury and should be used with caution.


Opamp Chips and Pedal Tone

Changing out the opamps are a great way to improve or change a certain pedals tone. Using a opamp socket makes changing out opamps a breeze.

JRC4558D

RC4558

RC4559P

LP353

NE5532

TL072

OPA2134PA

JRC4558D – Made by Japan Radio Corporation (JRC). Used in the original TS808s and TS9s. Ibanez later changed the chip used in their pedals. The JRC4558D is actually a very inexpensive chip that’s not considered Hi-Fi and was chosen because of its inexpensive cost and not for the tone it produced. It just happened to sound great when used with the Tube Screamers original circuitry. These chips are still very popular and are great sounding chips.

RC4558P – Made by Texas Instruments. Also used in the original TS808s and TS9s. Ibanez later changed the chip used in their pedals. The RC4558P is also a very inexpensive chip that just happened to sound great when used in a Tube Screamer circuit. These are still very popular today and are a great sounding chip. Very similar tone-wise to the JRC4558D, may have a little more grit.

LP353 - Made by Texas Instruments. Very similar tone-wise to the JRC4558D and RC4558P. Maybe a little less gain but an excellent sounding chip. Subtle differences. This is a very popular chip with pedal modders.

NE5532 - Made by Texas Instruments. Very similar tone-wise to the JRC4558D and RC4558P. I really like the tone and gain of this chip. In some ways I like it better than a JRC4558D or RC4558P. Rich, smooth gain with nice overtones. This is a very popular chip with pedal modders. Also a very low noise chip with great specs.

TL072 - Made by Texas Instruments. Very similar tone-wise to the JRC4558D and RC4558P. This chip has a very interesting tone. A little more complex than either of the chips above. Very defined harmonics, especially at high volume. This is a very popular chip with pedal modders and one of my personal favorites.

OPA2134PA – Made by Burr Brown. This is the most expensive opamp chip I sell. This is a very popular chip with audiophiles. It’s low noise and excellent sound properties make it a popular choice with pedal modders. I especially like this chip in a Boss SD-1. It has a little more edge than a JRC4558D or RC4558P and is a tad cleaner. Very rich and defined gain with excellent harmonics and note detail. You can’t go wrong with this chip. Highly recommended.

When changing out chips always take note of the way the writing on the old chip appears. You must install the replacement chip with the writing facing the same direction.


Capacitors

Capacitors - A passive electronic component that stores energy in the form of an electrostatic field.  In its simplest form, a capacitor consists of two conducting plates separated by an insulating material called the dielectric. Capacitance is directly proportional to the surface areas of the plates, and is inversely proportional to the plates' separation. Capacitance also depends on the dielectric constant of the dielectric material separating the plates.

The standard units of Capacitance:

Farad: F

Microfarad: µF (1 µF = 10-6 F)

Nanofarad: nF (1 nF = 10-9 F)

Picofarad: pF (1 pF = 10-12 F)

I know, I know, but what do they do? Well, a pedal’s capacitors help shape its tone. For instance, most stock Tube Screamers lack bass when the effect is engaged. By taking a couple of the stock .047uF capacitors up to .1uF or even .22uF you can increase bass response.

Common Capacitor Types and Pedal Tone

Polarized and Unpolarised Capacitors - Polarized simply means that there is a positive and negative side. These caps must be installed a certain way. With unpolarized caps it makes no difference which way they are installed.

Electrolytic Capacitors – These are polarized and have a positive and negative side. These are very common caps and are used in mass produced pedals because they are inexpensive. Replacing these cheap caps in strategic areas on the PCB is desirable and will lower noise and improve clarity and tone. It;s a good idea to replace these on older amps and pedals. They have a tendency to leak and go bad over time.

Ceramic Capacitors – Ceramic capacitors are not polarized. These are also commonly used in mass produced pedals because they are inexpensive. I’ve experimented replacing ceramic capacitors. I actually prefer the tone of these caps. For some reason to me they sound better than their expensive Silver Mica or other counterparts. I know others use Silver Mica capacitors but to my ears they have a tendency to sound strident and harsh.

Silver Mica - They consist of a mica layer (kind of glassy material) with silver damped on both sides. This is the most basic capacitor based on very good materials. Unpolarized. Some claim superior audio performance but I personally do not care for the tone of Silver Mica caps. Some of the most expensive caps made. The tone of Silver Mica sounds cold to my ears.

Tantalum – Polarized. Tantalum Capacitors are electrolytic capacitors that use a material called tantalum for the electrodes. Large values of capacitance similar to aluminum electrolytic capacitors can be obtained. This is my favorite capacitor for values above 1uF and above. These are great for pedal mods. They seem to really firm up the mids and bottom end and add clarity and note definition. And they have a small profile and fit well into small spaces on pcbs.

Polyester Film Capacitors - This capacitor uses thin polyester film as the dielectric. They are not high tolerance, but they are inexpensive and easy to find. These are the type you’ll typically find at Radio Shack. These sound okay but I still prefer Metal Film and Tantalum for pedal mods.

Metal Film Capacitors - Metallized film is used rather than film and separate metal foils. Electrical connection to the metallized film is made with a layer of molten metal droplets sprayed on each end of the capacitor, with lead wires welded to this "end spray". These are excellent for pedal mods. I use them for mod values 1uF and below. They are lower noise but more expensive. They are also becoming hard to source as manufacturers move production to surface-mount components.


Common Resistors Types and Pedal Tone

Resistor - The resistor's function is to reduce the flow of electric current. Resistance value is designated in units called the "Ohm." A 1000-Ohm resistor is typically shown as 1K-Ohm (kilo Ohm), and 1000 K-Ohms is written as 1M-Ohm

Carbon Film Resistors – The Carbon Film Resistor is made by coating ceramic rods with a mixture of carbon materials. This material is applied to these rods in a variety of means, the one most familiar are dipping, rolling, printing, or spraying the rods in the appropriate solution. The tone, to my ears, sounds a tad better, in certain components, than Carbon Composite and Metal Film. There’s a debate among a lot of people whether Carbon Composite resistors actually sound better. To my ears they do—my advice would is to try them and make your own determination.

Carbon Composite Resistors - They are made from carbon rods cut in the appropriate length then molded with leads attached. The mix of the carbon can be varied to change the resistivity for the desired values. The tone, to my ears, sounds a tad better, in certain components, than Carbon Film and Metal Film.

Metal Film Resistors - Metal film resistors are manufactured by an evaporation/deposition process. That is the base metal is vaporized in a vacuum and deposited on a ceramic rod or wafer. Arguably the best resistor type. I personally prefer Carbon Composite and Carbon Film. I suggest trying each and making your own determination.


Diodes

Diode - A diode is a semiconductor device that allows current to flow through it in only one direction. Although a transistor is also a semiconductor device, it does not operate the way a diode does. A diode is specifically made to allow current to flow through it in only one direction. A diode can be used as a rectifier that converts AC (Alternating Current) to DC (Direct Current) for a power supply device. Diodes can be used to separate the signal from radio frequencies. Diodes can be used as an on/off switch that controls current.

Common Diode Types and Pedal Tone

1N34A Germanium - The 1N34A Germanium diode is an old standby in electronics. Widely used for detecting the rectifying efficiency or for switching on a radio, TV or stereo etc. Depending on where in the circuit these are placed they can have an excellent affect on the gain and clipping of a pedal’s effect. I love the tube-like texture these diodes produce. Very smooth tone. Use these to take the raspiness out of a pedal’s gain structure. In certain circuits can add a very fuzzy type gain structure to the pedal.

1N4000 Series Diodes – A general purpose silicone rectifier. 1N4001 thru 1N4007 may be used with equally good results. If you want more volume with a slightly rounder gain then the 1N4000 series diodes are the ticket. Strategically placed, these diodes can have a dramatic affect on the tone of a pedal. Generally if I feel a pedal needs less highs and less raspiness in its gain, I will replace the clipping diodes with one or two 1N4002 diodes.

Zener Diodes – These are diodes that regulate voltage. Voltage regulation is a useful diode property to exploit. Suppose we were building some kind of circuit that could not tolerate variations in power supply voltage, but needed to be powered by a chemical battery, whose voltage changes over its lifetime. We could form a circuit as shown and connect the circuit requiring steady voltage across the diode, where it would receive an unchanging 0.7 volts. The LED of your pedals is regulated by a Zener Diode. The LED cannot take a full 9 volts so the zener pulls that voltage down to acceptable levels. Without a zener diode the 9 Volts would burn out the LED.

LEDs (Light Emitting Diodes) – LEDs will increase output and some feel they give a pedal a more tube-like type of distortion. I now sell these at my website for those that like to experiment. These are great for shaping the gain structure of your pedal. If you're looking for more volume try LEDs. They have a higher forward voltage than other diodes.

There are several other diode types and each will have a different affect on a pedals tone. Go ahead and try different ones and see how they affect your pedal’s tone. It’s fun and you never know what you might discover.


Gentlemen Start You Soldering Irons

How to Desolder

First identify the component by marking the contact pads on the bottom side of the PCB with a sharpie. Now take your desoldering braid and lay it on top of the solder joint with the soldering iron on top. The heat will draw the molten solder into the braid. Be careful not to let the braid solidify onto the joint. Also be careful not to overheat. If the braid becomes stuck to the joint simply reheat until it separates. If you meet resistance do not force the component out or you may pull the trace pad from the PCB. If this happens and the pad breaks loose you could permanently damage the pedal. IMPORTANT: Be careful to remove all the solder. If solder remains on the component you are removing and you try and remove it you could pull the trace pad from the PCB. Take you time, removing the solder is not difficult. It’s when we get in a hurry that we make mistakes.

Important Note: I always like to save the components I remove by placing them in a sandwich baggie. I also recommend taking notes along the way. Document with pen and paper which component you modded and what value it was. This makes backtracking easy if you decide you want to restore a modded component to its original state. 


How to Solder

Good soldering technique takes practice. The more you do it the easier it becomes. It’s important to keep the soldering iron’s tip clean. Use the damp sponge to wipe the tip after each time you use it. Debris can cause a bad solder joint and noise is a circuit. After soaking and mopping up the solder from the component you’re replacing, take the new component and place it into the PCB. Be sure and spread the components legs apart. This will keep the component from falling out when soldering. Now place a clean iron to the pad and apply a small amount of solder. Do not apply too much solder or you run the risk of soldering two pads together and shorting the circuit.

A good solder joint will have the appearance of a pyramid as seen. A dry solder joint should be avoided. Once the component has the solder applied, trim away the excess component legs with your wire cutters. IMPORTANT: check the pedal after each mod. You don’t have to reassemble, just plug in the cables and see that everything is working. I like to install a battery in the pedal I am modding so I don’t have to worry about plugging and unplugging the AC adapter.


Getting Started

Once you have the right tools and a general idea of what each component mod does, you are ready to begin modding. IMPORTANT: I know I keep repeating myself but this point needs to be driven home. Check the pedal after each mod! You don’t have to reassemble everything. With the back cover off simply plug in the cables and test to see that all functions are operating properly. Check the LED also. It’s very easy when modding for a wire to come loose. I like to check all wire connections prior to modding and make sure all the connections are secure. This will prevent surprises later. Remember, some components such as Tantalum Caps and Diodes have a positive (Cathode) and negative (Anode) side. If they are installed backwards the pedal will sound funny or muffled or may not sound at all. WARNING: Installing an op-amp chip incorrectly will more than likely fry the chip. Also, electrolytics will explode if installed backwards so pap attention. Take special care and make sure it is installed correctly.

The first thing you want to do is identify the component you are modding. Take a fine point Sharpie and mark the solder contacts on the back of the PCB. Take your time and make sure you have marked the correct contacts. It’s easy to misidentify them because they are so close together. Flip the PCB back and forth until you are certain you have the correct contacts, and mark them with a sharpie. Now take your desoldering braid and place it directly on top of a contact with the soldering iron directly on top. Apply only enough pressure to adequately remove the solder. Make sure all the solder is removed. If solder remains and you try and pull the component out you could pull the trace off the PCB. Believe me, you don’t want this to happen—it’s a good way to ruin your pedal.

Once you are sure all the solder is removed, take your needle nose pliers or a small screwdriver (depending on the component you are modding) and remove the old component. TIP: Save the old components and place them in a zip-lock sandwich bag—you may need them later. I also recommend documenting each part you remove. For instance—you remove a cap that has 473k (.047uF) written on it and it came from C17 on the PCB. Write C17 on a piece of paper with 473k out beside it. After playing the pedal a while you may decide you want to go back to the original component. By documenting the mod this will make going back very easy. Also, be careful with your soldering iron, excess heat can damage the PCB traces or the components. I recommend a 15-watt soldering iron.

Once your target component has been desoldered and removed, take the component mod and place it in the PCB. If the component is polarized make sure it is placed correctly in the PCB. If you are replacing a diode, the PCB will have a triangle telling you which is the positive (Cathode) and negative (Anode) direction. The triangle will have it’s point in the direction of the positive (Cathode) side. Once the component is inserted into the PCB correctly, take the legs of the component and bend them outward as seen in. This will keep the part from falling out when soldering. Now take the solder and your gun and solder the part onto the PCB. Use only enough solder to form a shiny pyramid type joint. Be careful not to spread solder into any adjacent contact that will short the pedal out.

Diodes, Electrolytic Capacitors, Tantalum Capacitors and Op-amp chips have positive (Cathode) and negative (Anode) sides. These components must be installed a certain way. Diodes are easy because the PCB will have a triangle with the pointed side pointing to the positive side. Electrolytic caps are marked on their negative side while Tantalum caps are marked on their positive side. Like-wise on the PCB an electrolytic cap is marked in the negative side as seen in and tantalums are marked on the PCB with the positive side as seen in. Diodes, with the exception of LEDs, are marked on their positive side by a stripe as seen in. LEDs usually have a longer leg on the positive side, but this isn’t always the case. TIP: Take a 3V watch battery and contact the legs battery. When you have contacted the correct positive and negative sides the LED will light up. Op-amp chips will always have writing on them. Always reinstall the replacement chip with the writing in the same orientation as the original chip.

Trim away the excess legs of the component with a pair of wire cutters. Now plug the pedal in and check to see that it is working properly. Check the LED also. Sometimes a wire to the LED can come loose. I’ve had this happen more than once. If there is a problem, check the contact first to see if solder has spread to another contact. If it has, simply remove the excess solder with your desoldering braid, and resolder. If the pedal is still not working, check to make sure a wire hasn’t worked loose somewhere on the PCB. If one has, it’s usually very easy to identify where it goes. I like to check the connection of all wires before modding. As long as the wires have secure solder joints they will not come loose during modding. Loose wiring is the main cause of pedal modding issues. Once everything is working, proceed to the next mod. TIP: some mods require a jumper to be placed where a component is being removed. Take the excess you trimmed from one of your previous mods and use this as your jumper.

Make sure you keep the end of your soldering gun clean and free from debris. Use the pad that comes with your soldering gun holder and wipe the tip clean on the damp sponge after each component mod. By keeping the tip clean you will ensure a smooth and clean solder joint. Debris can become embedded in the solder joint causing a bead to form on the joint. By keeping the tip clean you can avoid this. 

Replacing the LED

To add a really nice touch I like to replace the original LED with a super bright LED. I also like to change the color of the original LED to something different. For instance, I will change each pedal in my live rig to a different color LED. This way I can glance down and immediately know which pedal effect is currently on. I usually use a super bright blue LED for my BD-2 Blues Driver, a super bright yellow LED for my SD-1 Super Over Drive and a super bright white LED for my CS-3 Compressor. I now sell several 3mm and 5mm Super Bright LEDs at my website here.

More Modding Tips

The really great thing about pedal modding is that it puts you in control. We all have this idea in our head of the tone we want to hear. As you become more familiar with just how each component affects your pedal’s tone, you can start to shape your pedals tone into just exactly what you, as a player, want the pedal to sound like. It’s amazing just how inexpensive some of these pedals are. There are great deals to be had on eBay for used pedals. A modded pedal can easily be made to sound as good as effects pedals costing two to three times its cost. Most of the boutique pedals on the market are clones of existing pedals anyway. The only difference may be a few component changes here and there.


Advanced Pedal Modding (Series, Parallel Connections, Toggle Switched and Potentiometers)

By using series and parallel connections for different components you can obtain unique and sometimes surprising results. A series connection will look like this. A parallel connection will look like ths. Try two diodes in series or maybe a capacitor and diode in parallel. Get inventive, you’ll be surprised at the affect these will have on your tone. I like to put two diodes of different types together in series and parallel. Or maybe two of the same type diodes together in series or parallel. I also like to add a toggle switch on certain mods. For instance, you could place a toggle switch on two capacitors and have the switch toggle between a .047uF cap and a .1uF cap. Here’s an example of how this would be accomplished. Using this same technique with two different types of diodes will also give you a wide variety of tones.

When adding toggle switches you will need to drill holes into the case of your pedal. You’ll, of course, need a drill. Make sure you place the toggle switch in an area of the pedal that doesn’t interfere with other components once the pedal has been reassembled. Also make sure the components hooked up to the switch do not short out other components in the pedal. Use electrician’s tape when necessary. You can also add a potentiometer to a component. Want varying amounts of gain or bass—add a pot. Want more or less mids—add a pot. Your options are unlimited. I’ve gotten some pretty amazing results by just breaking all the rules and trying different things. You never know what a little experimentation might yield. Did you know you could stack two op-amp chips together, solder the legs to the legs on the bottom chip.

Something to keep in mind while pedal modding—all components have a voltage rating. The minimum voltage rating for pedal components should be 16 Volts (16V). Any less and you run the risk of damaging the component or worse you might damage other components in the pedal. Most pedals are 9 Volts (9V), but voltage can fluctuate a bit with power supplies, so to be safe a minimum of 16V is desirable.


Final Thoughts

The guitar has given me so much over the years. In my teenage years it was a way to express myself—and I felt it helped me be accepted by others. It has taken me places I otherwise would not have gone, and has allowed me to meet people I would otherwise never have had the chance to meet. The joy and pleasure it has given me is immeasurable.

Today is (January 6th, 2017). I enjoy playing as much today as I ever have. Music is such a universal language. It allows us to connect on a level that transcends race, religious preference or culture. It makes us happy and it makes us sad. It can make us sorry and it can make us glad. The emotions it stirs in us can be used for good and bad. I personally feel music has healing properties. The power of music is pretty amazing. How you use it is totally up to you. Just remember, when much is given much is required. Use your talent and abilities wisely. The past is filled with young talent whose candle burned out way before their time. The seductions of the music industry have laid waste to many a talented player. Don’t become a statistic! Take care of yourself. Don’t sacrifice a few moments of pleasure for a lifetime of happiness.

There was a time when I thought I had to get high to have fun and enjoy music. That type of life is a vicious lie and ends with pain, suffering and sometimes death. Today I am sober and healthy. I enjoy playing guitar today as much as I did when I was 25. Take care of your body; you’ll need it one day ;-).

Play hard, practice hard and the guitar will take you places that will blow your mind. Remember, there’s a reason the present it called “the present”. It’s a gift—use that gift wisely. Embrace it with a smile. Use it to bring happiness to others. Live each moment like it’s your last. Don’t wish your whole life away. Make it happen. You are the master of this ship called life. There’s absolutely nothing you cannot do if you have the desire and will to make it happen.








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