“POP!” Goes the Effects Pedal: How to Fix That Annoying Sound

Today I figured I’d clear up something very simple. This will be short, I promise. Many times people will ask me about replacing a switch on an effects pedal because it makes a popping sound when they turn it on. They figure that the noise is coming from a cheap switch that passes that sound through the effect from the movement of the pieces in the switch. The interesting thing is that the switch is most likely not the culprit. So what the heck is it?

In nearly any effect pedal circuit there will be a layout of resistors and capacitors among many other parts. The capacitor is an electronic part that has many functions, one of which is to control signal and electricity flow from power sources (electrolytic capacitor). To do this a capacitor will conduct AC (alternating current) while it blocks DC (direct current) . However, there is an act that these little buggers like to play called “leakage.” Basically, in a true bypass pedal, when the circuit is bypassed the capacitors are within an open circuit. This can change their DC voltage a bit (through leakage). When the pedal is engaged, these capacitors have to charge back to their usable voltage. That sudden voltage change causes the pop that you hear. The more gain your pedal is capable of the louder that pop will be as the circuit will amplify it as it travels through. Never fear! There is a fix.

In some circuit you may see a large value resistor  (1M-10M) going directly to ground. This resistor is usually directly after the input resistor. Some circuits will have another large resistor directly before the output. These are called pull down resistors. Their purpose is to take that sudden voltage change that is being sent through the circuit and dump it off to ground. That way the pop never leaves the circuit and you don’t hear it! The pedals that do not have these (usually vintage or very simple designs) are more prone to the popping phenomenon.

Another culprit to the pop is actually due to the LED. The sudden surge of current going to the LED when the pedal is engaged causes an audible pop!  In this article, Jack Orman explains in more detail, however there is a pretty simple fix for this as well provided you are comfortable with a soldering iron. By adding a simple resistor/capacitor circuit in which the negative side of the capacitor is connected to ground while the resistor is in series with the limiting resistor and 9V supply you can virtually eliminate that annoying sound. Here’s an example from the Jack Orman article.

Noise reducing circuit

Take care of that POP!

The R2 and C1 have been added to take care of the popping noise. Essentially this added circuit creates a delay to the current so that the charge is not so sudden but allows the LED to light up fast enough that your eye will not notice a difference.

So the next time you stomp on that vintage Fuzzface or RAT pedal and hear that POP echo, don’t think about touching that switch. Just add a few simple parts to the circuit and you should be good to go.

Nov 15, 2012

Point to Point, PCB and Veroboard Pedal Wiring: What’s the Difference?

So there you are, staying up far too late again looking through reviews of effects pedals, watching demo videos, searching for that ONE piece that will finally put you in sonic bliss. Then, the moment you’ve feared most… the manufacturer product description.

It’s no secret that most of them read like a combination of an Einstein science paper and a Shakespearean play. That’s no accident, it’s part of the marketing, hype and buzz building technique! Although there are many points of confusion among product descriptions, right now we’ll be clearing up the pedal wiring conundrum. What’s the difference between handwired, PTP (point to point), PC boards and vero, or stripboards? What’s more, are any of them actually better than the next?

First, let’s explain what each of these are. True PTP wiring features the shortest run of leads from point to point, which is where its name comes from. In PTP wiring all components are wired directly to the controls and tube sockets with the maximum amount of space between leads that keep the leads as short as possible. This type of construction requires very careful planning and skilled hand. PTP wiringHere is an example of PTP wiring from an article by RG Keen.

Contrary to popular belief (and marketing ploys) the kind of construction that is most often referred to as PTP is not PTP at all. Turret board (as in most “PTP” amp chassis) is not PTP wiring. Turret boards, like the Turret board amp wiring shown here from the same RG Keen article, use wire runs to complete the connections to the tube sockets and controls.Turret board amp wiring


Similar to these ampflifier wiring examples, wiring in a pedal board is no different. True PTP wiring would essentially mean components are wired directly to each other and directly to jacks, pots and switches. Obviously the ability to do this in a small, pedal enclosure makes this type of construction either impossible or extremely time and resource consuming. You may see a handful of fuzz circuits that fit the bill, simply because most fuzz circuits have less components than others and are usually all analog circuits.

PTP wiring

PTP example from Fromel

Other than that, this is the main reason so many people in the effects pedal biz have come to call turret and strip board construction PTP. Most often, this is the closest you can get to true PTP wiring while still working with the space constraints of the enclosure.

That brings us to PCB. We all know what a PC board is, that little green board inside your TS808 that houses all the magical components and traces that send the tone shaping goodness from resistor to capacitor. PCB is often used for a few reasons, most notably to save time and in turn save money. However, it should be noted that without the time savings that come with PCB construction it actually costs more to use the boards. It’s an added expense as opposed to PTP, and usually costs more than strip/veroboard construction. PCB is used by the big manufacturers to create effects pedals that are cost effective AND standardized. Although you could buy two of the same pedals that are PCB constructed and have them sound a bit different, more often than not the pedals will be close to identical, especially in modern effects pedals.

So now that we understand what each type of construction is, let’s talk about the elephant in the room. Which one is best? Well, the answer is obviously PTP… right? Well, maybe. The fact is that a poorly designed PTP wired pedal can be awful. In the same way a PCB designed pedal that is done well can be great! The use of PCB or PTP wiring has little to do with the actual “integrity” of the tone. It’s more about the reliability of the design, layout and quality of parts used. So where did this folk myth originate? Well, usually when a builder goes from PTP or turret board construction to PC board construction it is to save time so they can make more pedals in a shorter amount of time so they can make more money. USUALLY this comes along with other cost saving initiatives as well, like cheaper components. Thus, the myth is born. People don’t take the time to see what types of components are being used in a PTP pedal as opposed to its PCB counterpart. They just plug both in and dig the PTP pedal more! Now, without getting too deep in the technical stuff, PTP wiring does come much closer to “ideal” electronics. This means that if it is done well there is a minimum amount of crosstalk and parasitic coupling which leads to unwanted capacitance. However, many modern PCB constructions take these things into account. The point is, in effects pedals if the work is done well PCB and PTP construction can both lead to a great sounding pedal.

At Mercy Seat Effects I use veroboard construction for my builds. This means the components are loaded onto a small board with copper strips that carry the signal from point to point. I won’t hype this into something it isn’t. I won’t lie to you and tell you that this is better than PCB construction. The fact is that I do it because I am most comfortable with this type of construction. How many pedal builders do you know are that open about their techniques?

I would highly suggest reading this article from RG Keen. He knows his stuff and knows it much more than I. If you’re interested in this topic he actually addresses a lot of the types of myths that get started in the guitar electronics realm at the end of the article. Really good stuff.

Nov 07, 2012

Buffers: When Do I Need One and Why?

Mercy Seat Effects Samson BufferBuffers, in my opinion, may be one of the most misunderstood pieces of circuitry involved in the guitar chain. Too often players rush out and buy a buffer because they’ve been told it is an essential piece of gear. “If you don’t have a buffer your tone must suck.” Well, maaaaybe. In this article we’ll talk about what a buffer does, what it is meant to do and how you can tell if YOUR tone might benefit from the addition of a buffer in your guitar signal chain.

First, it is important to point out that many players may have a buffer in their chain and not even know it. Most Boss effects have a built in buffer. This means that even when the pedal is not engaged the guitar signal is still running through buffing circuit, also known as NOT true-bypass. The quality of these buffers of course has been a source of debate for some time. In my honest opinion, the buffers in most Boss pedals are a very decent quality. Another classic pedal that include a buffing circuit is the infamous Ibanez Tube Screamer. So why does this matter? Well, the fact is that if you have a couple Boss pedals in your chain already you probably don’t NEED another dedicated buffer, but we’ll get to that.

What does a buffer do?

So what does a buffer even do? Good question. Without getting too deep in the the complexities of electronics, essentially a buffer is designed to bring the life back to your tone, mainly in the high-end, by converting the relatively high impedance output of your guitar pickups to a low impedance. This conversion gives your guitar signal the “strength” it needs to complete the journey from your pickups all the way to your amp with the lowest amount of signal or tone loss possible. A good buffer is designed to be a 1:1 ratio, meaning the tone and volume going into the buffer is exactly replicated. This is one major misunderstanding. A buffer is NOT a boost. It is not intended to increase volume in any way. This misunderstanding is most likely due the fact that a lot of boost pedals also have a buffing circuit.

The work that a buffer does can be a bit hard to notice sometimes. In other cases a player may get that “blanket taken off my amp” type effect. It all depends on your signal chain. It is fair to say, however, that most players will notice a return of high-end sparkle that they may have not even known was missing until they put a buffer in the chain. There are a few tests you can run with your rig to see if you might need one that we’ll get to in a second, but a few quick questions you can ask yourself are:

How long are the cables you use? Even a 20 ft. cable can introduce around 800 pf of impedance between your guitar and amp. That’s actually quite minimal but when you start adding effects in the mix that number can jump up quickly.

How many true bypass pedals do you have in the chain? If you’re unsure whether an effect is true bypass or not, plug your guitar into it, make sure the effect is OFF and then remove the power source going to the effects pedal. If you still get a signal going through then the pedal is true bypass, if not then the pedal has some sort of circuitry that the signal is passing through before leaving the pedal and without a power source that signal dies. If you have more than 4 or 5 true bypass pedals along with a couple 20 ft cables going to and from your effects board you should probably think about adding a buffer. If you have a couple Boss effects in the mix, like a TU-2 tuner or DD-5 delay or whatever, then you might have enough buffing going on already.

Another quick point is that pedals can always be modded to be true bypass. If you have a Boss tuner but you still don’t dig your overall “sparkle” you might think about having it modded or replacing it with a dedicated buffer and a true bypass tuner. You can also use a true bypass looper that will take the non-true bypass effects out of the signal chain when they are not being used. Only YOU can make that call.

What can I do?

Okay, so now something you can DO to test how your tone may improve with the addition of a buffer. First, plug your guitar directly into your amp. Don’t mess with the controls just play a few notes and chords and take note of the tone. Even better, record a quick 20 to 30 second clip playing something. Now, without changing any controls on your guitar or amp, send your signal through your pedal board with NO effects on. Play the same notes and chords you played earlier, recording if necessary. You’ll probably notice a difference. How substantial that difference is will vary from rig to rig. The addition of a buffer at the beginning of your chain will bring back the tone you heard when plugging directly into your amp… or at least VERY close to it.

In closing I’d just like to point out a few things. Your tone is just that, yours. Too often it is easy to buy in to marketing and hype. If you dig the way your rig sounds without a buffer that’s awesome! Legend says that Albert Collins used a 120 ft cable from his guitar to his amp (no buffer) because he liked the way it sounded! So don’t just buy a buffer because you think you’re supposed to have one. However, if you like the tone you get going directly to your amp and wonder how you can get that same clean tone with a pedal board in between then look into adding a buffer.

Ty Cobb

Sep 19, 2012
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