Archive for the ‘Colorless Writings’ Category

Colorless writings, part 15 – Fuzz vs. Overdrive vs. Distrtion

Saturday, September 13th, 2014

I found myself in very weird situation. Today, i simply had nothing to say. But i can’t pass on a colorless writing, as that would mess up my OCD. I did start on one more demanding subject, but i realised i won’t be able to finish it without messing up my schedule. So i just needed to drop that topic (it’ll be featured as part 16)  and write something else instead. I needed a subject that would be easier to cover. So why not bring up this age old question about how to categorise the effects that produce distorted tones.

Fuzz versus Overdrive versus Distortion?

Exactly. How do we tell which one is which? How can we be certain that a Tubescreamer is in fact a overdrive effect rather than a distortion? We can’t. It’s more likely all in the marketing speak than in real world electronic designs. Let’s start with the early days of distorted tone. Legend has it that certain guitarist for a group called The Kinks used a razor blade to slash a cheap combo amp’s speaker cone to get that distorted sound for one 60’s hit recording. Later in the sixties we were blessed with a ton of fuzz effects that were designed to mimic that broken speaker cone. The most basic fuzz design was (and still is) called a shunt-series feedback amplifier. The circuit was well known before any fuzz pedal was  ever produced. The fact that a guitar’s output is enough to push this circuit to sweet distortion wasn’t exactly mentioned on the text book the circuit was originally from. But there you have it. A very first electronic guitar effect that gives out a distorted tone.

In early seventies other types of pedals started to emerge. Some were called boosters and some were called distortion boosters, but they were still mostly boxes with fuzz sounds coming out of them. Later in the seventies, the dawn for Tubescreamer, DOD OD250, MXR Distortion+, Boss OD-1, DS-1 and ProCo Rat widened the spectrum of distorted tones available. That may not be complete list of units that suit the bill, but it’ll get us going. It must have been in those days when the split happened.

Let’s look at the OD250 and Dist+ first. These two pedals share the circuit topology with each other. Main difference is the type of hard clipping diodes after the gain stage. OD250 uses Si diodes with lower voltage drop and more volume, while Dist+ has Ge diodes with higher voltage drop and less volume. This means that the sound of these is very close to each other. Nevertheless, the former was (and still is) marketed as Overdrive/Preamp and the latter as a Distortion. You guys must now be getting my point?

Boss DS-1 works in same principles as the two, but it has more driving stages. ProCo Rat has similarities too, although its gain control isn’t even close. I’d like to point out that some Rat versions had a text “fuzztones for connoisseur” printed on their circuit boards. So is the classic Rat a Distortion or a Fuzz?

The debate may still be going on which one was the first to take clipping diodes to the feedback loop of non-inverting amplifier and creating softer clipping. Usual answers to this 40 year old debate would be TS808 and OD-1. I have no idea which was the first, so i’m not going to waste my time in speculating about that. There are hundreds and hundreds forum posts about this subject to be found on the interwebs. In case you are interested. These pedals with soft clipping are usually referred as overdrives. Although, there are numerous distortion designs out there with similar clipping diode arrangement.

To sum it up?

A fuzz. This should the easiest one to point out. No clipping diodes and no opamps. Just a bunch of transistors driving the hell out of each other in order to create clipped or distorted signal. But is it that simple? As usual, no. Take a EHX Big Muff Pi for example. This design (and its hundreds of derivatives) is often referred to as a fuzz. Another nice examples would be Anderton’s tube Sound Fuzz and Colorsound Tonebender reissue from the 90’s. I’d call all of those distortions or overdrives rather than fuzzes.

Going forward with the Distortion. This one may be simpler. Hard clipping diodes. But even here, this may not always be the case. There are pedals like ZVex Distortron that is usually considered a distortion, but to my ears it sounds (without going any further on its electronics) a way more like an overdrive. As the earlier example with OD250/Dist+ shows, the design with hard clipping could also be called just about anything.

Overdrive? Now this leaves us with soft clipping and thus, these should be easier to identify. But no. If we take a look at good ol’ Way Huge Red Llama overdrive, we’ll see it’s way closer to Anderton’s Tube  Sound Fuzz than any other OD we’ve seen. There are a number of JFET-based overdrives too. These may not have clipping diodes in them at all, but they will still offer full soft clipping sounds.

Is that what you call a sum of the subject?

Well. Maybe not. But it does show us one thing. There isn’t one clear, or even fuzzy logic to when we call a  circuit a fuzz, overdrive or a distortion. It’s all in the head of designer at first – then in the heads of the people at the marketing department and after that – in our heads.

Sure it would be easy for me to think that these pedals are fuzzes, these  pedals are overdrives and these pedals are distortions. But that won’t do. We can’t define something that’s completely undefinable. And since there is not a way to define which is which, we all may face the situation where our newly bought a) fuzz sounds like a distortion, b) fuzz sounds like an overdrive, c) overdrive sounds like a fuzz, d) overdrive sounds like a distortion, e) distortion sounds like a fuzz, or f) distortion sounds like an overdrive.

I’m going to leave you with one summing thought – there is no way to define or categorise which is which, from electronic point of view. It’s all in the marketing and in our heads.

This does easily apply to all the other pedal genres as well.

Colorless writings, part 14 – Overcoming the shortcomings

Sunday, August 17th, 2014

So what shortcomings are we talking about this time?

Shortcomings of a classic fuzz circuits. Sure i could rave on about hundreds and hundreds of boosters, overdrives and distortions that simply can’t overcome the unity level of your guitar. In my books that’s a shortcoming. But maybe i’ll reserve those for another part of my writings. Let’s just go with the fuzzes for now. To get to the bottom of this behavior, we must understand what the guitars were like 50 years ago. The term “vintage output” for pickups does have a meaning. DiMarzio was the first manufacturer to offer aftermarket pickups. Meaning that before 1972, swapping the pups for better ones wasn’t exactly an option (for the word better, we’d need to define what’s better, but you’ll get the idea). Swapping pickups on existing guitars and paying more attention to those became widely popular later in the eighties. Which means that all the classic effect pedals from 1966, all the way to beginning of 80’s were designed to work with old school standard pickups that were shipped with sold guitars. Usually having  low or lowish output pickups. Think about PAF style humbuckers for example. They have very nice tone, but the output is still low. I’ve noted before that once your pickups have high enough output, that can turn the effect to sound mushy, and simply put, bad. Other chance is that the output is too high for the circuit design to add any real current to the signal.

To me, it’s very annoying to notice that otherwise good sounding re-issue of Fuzz Face can’t boost the signal coming from my favorite humbuckers. Now, these humbuckers give out highish output and they sound reasonably good without being too harsh. When i play with clean sound for most of a song and want the upcoming lead to stand out, i simply can’t choose this Fuzz Face re-issue to be the pedal to do that. Not by itself, at least. I’ve seen this same behavior with many other effect designs from the past too.

Got it. So how to overcome this issue?

Breaking every single rule i ever had for my colorless writings, here’s a schematic for very generic silicon fuzz face. (Sure, these images have no color except for black and white, so i can let it slide)

Generic-Si-FuzzFace

You can find about a hundred similar schematics with internet image search. There is also very comprehensive article published by R. G. Keen. But i’m talking about simple silicon version with common negative ground power requirements. The 47R resistor from Q2 emitter is there to tame some of the hiss, oscillation and excess noise that high(ish) gain silicon transistors in this configuration can be prone to emit. The TR1 is a trimmer for tweaking the bias voltage for the transistors. I always tune bias by ear rather than using some known voltage. Every transistor is unique in their gain factor and the pickup signal is another factor for the correct bias,  so one exact voltage for all situations won’t cut it. Plus the controls on the classic pedal are, in one word, crap. 1k linear pot for fuzz control means that all the usable range is in the last three percent of the sweep. And i don’t want to go further to the volume control. To sum it, both controls have one usable location. That being maxed. Anyway. This is the circuit that sound very nice when played on single coils with vintage output. Circuit can do some boosting in this scenario. But since it simply cannot do that with modern pickups. If you have ever tried a clean booster after a FuzzFace in you effect chain, you know that will sort the problem. It isn’t very convenient solution though. To change from your base sound to soaring lead, you would need to jump on two stomp switches. So why not take a simple one transistor boost circuit and place that after the standard fuzz as an internal post boost? This way we’ll have most of the original tone and frequency response in tact, but we are addressing the low output.

Here’s my evolved Fuzz Face. Standard fuzz circuit with a bias trimmer and everything exactly as before. Minus the reverse logarithmic taper for the fuzz pot. The output has been dramatically improved.

FYA-EFF2-Fuzz

There is nothing exactly new or special about it. If we look at some details, there are your modern standard 3PDT stomp for true bypass, including a 1M pulldown resistor at the input to address possible pop side effects caused by mechanical switching. One could, of course, use way higher value for that resistor to prevent it from loading the input. This switching method also grounds the circuit input when bypassed and there’s a 12k resistor for bright white LED too. DC connection is wired for standard battery (which i never use for my builds) switching, which takes the battery connection out once the input jack has been disconnected. Power supply section has a 47µ filter cap and a series polarity protection (taken care of by low voltage drop Schottky). The base topology for the fuzz is in tact with its 2µ2 input cap, bias trimmer and a swapped reverse logarithmic fuzz control pot. There are other ways to gain reasonable sweep for this control by creating a custom taper, but for this drawing we’ll settle for rev. log. Some might have noticed that the fuzz output cap value in both of my drawing is 100n. Many similar designs have a lot lower value in that position, which leads to more tighter, trebly and nasal overall tone, especially when the level control is maxed. Personally i like the feel of a fatter tone, so 47n or 100n for me. Now all up to this point will produce the same tone as the smaller, more generic example.

The rest of the circuit is not completely different from one classic one transistor booster marketed by one Electro-Harmonix. It is a simple one transistor amplifier with low parts count that colors tone tone only a little. The output of this amplifier is coming to a 100k trimpot which acts as a Master Level trim.

Why do you have the level control for the fuzz where it originally was? Why not use that Master Level as an level control?

Good question. And i have a simple answer. To keep the frequency responce of the fuzz as close to the original as possible. Since the boost amplifier colors the tone only a little, we don’t want its output to change the frequency response in the same manner as the fuzz’s level control does. Instead of this arrangement, we coud use a JFET or even an opamp to boost the ouptut, but former would be better off with a bias trimmer and the latter would need its own refence voltage network. To keep everything simple and neat, its not a bad practice to go with this solution. Ah. There would be so much more to talk about what’s going on with this circuit. But i’m going to leave you with the information above and two notes – Breadboard it. Fuzz face is a highly tweakable and good sounding tiny circuit. There is always room for more and more tweaking. You should try to make it better for yourself. And another; want one? Sure, i can build you one..

Colorless writings, part 13 – The Power

Saturday, July 19th, 2014

I just noticed something. It’s been exactly one year since i started the current reincarnation of this blog. Since 19th of july 2013, i’ve written 144 posts. Eleven and thirteen bi-monthly. This post marks 13th Colorless Writing, which also mens that i’ve written my reviews/analysis on 130 pedals so far. To be honest, i’m not sure if can keep the pace as i may run out of pedals to write about at some point. Maybe a little less per month should suffice… Anyway. I’d like to thank you, all my readers. Thank you. Now let’s get over this crap and talk about Power!

Powering up the pedals are we?

Yup. It’s been a while since i started to read Denton J. Dalley’s book called Electronics for guitarists. The first edition is up on the web for grabs, but i didn’t know that at the time i bought myself a paperback version of the book’s second edition. The first edidion has most of the information, but second has over 200 pages more and it’s been updated on many subjects. Not to mention there’s a foreword by Billy Zoom. This book is highly recommended reading by the way.  The book starts out by saying a thing or two about the power. In our modern world we get our electricity through our wall sockets and what we get is a alternating current electricity. AC has a lot advantages when we need to transfer that power from power plant to our houses, rehearsal studios and clubs we gig at. The loss is a lot lower than what it would be to transfer DC current. To be exact, the DC would be real pain to move if we need to have more than fifty meters between the supply and the user. So what does this all have to do with our gear? Well. Everything from amplifiers to your pedals require direct current to work. Only thing that’s AC in our gear is the guitar’s (or bass’) signal itself (and some parts of our amplifiers, but i’ll disregared that for now). And that DC we’re hoping to use should be as stable as possible.

I’m not about to go too deep in AC power part, but think of a straight line where that line is zero volts. Now picture a sine wave going up and down that line, upper half reaching +120 volts and lower half -120 volts (that’s for us europeans). That’s what the AC coming from your wall socket looks like in theory. There are different phases to it, usually three, but the one is enough for our examples. Now, we need to turn that power in to a stable DC source for our pedals.

There are basically at least two things we need to do that. First, the transformer. What that does is it drops the voltage down and bounces the bottom half of the sine wave we discussed a second ago to the upper half, making the upper half a DC source. Let’s assume that this transformer is something we may find in standard 9V wall wart power supply. That’ll make the DC voltage appear on the line, but the dropping the voltage to something like 13-15 volts. Since the AC looked like a sine wave on that line, pushing the bottom part to top part doesn’t make it stable 13-15 volts. Sine wave stays in the equation, it’s simply pushed between zero and 13-15 volts instead of being where it was – between zero/minus and zero/plus. Due to sine wave looking like it does, there are bound to be lower voltages on along the line with our DC we got out of the transformer. For example, the new DC voltage could vary from +12 to +16 volts after the transformer.

And that’s called the ripple effect?

Exactly. Now, if we were to push that DC voltage to our pedals, we’d notice a high noise floor, hum or even loud oscillations and and other unwanted noises on some pedals. All these issues are usually generated by unstable, unregulated DC source. The second thing we need for a DC supply is a regulator. Regulators like 7809 are designed to take slighty higher voltage than their output and levelling the ripples. These regulators also need a few filter capacitors to function right. Since in this case we want regulated 9V DC output, the input for the regulator needs to be at least 12V. That’s why we used the transformer above to generate unregulated 13-15 voltage. The regulator cannot up the voltage, so if you feed the 9V regulator only 7 to 9 volts, you won’t be getting out nine, but a lot lower reading. It will need that 12V to fuction properly.

And next i’d like to take a look at the filter capacitors. The regulator usually wants some form of ripple filtering before its input and after its output. Let’s say that out wall wart in this case has 47µF caps at those positions. We may still have some ripples left, as even the best transformers and regulators are subject to what we feed them. Not all wall sockets offer neat and perfect sine wave. There will be variances. This is why we want and need to have power filtering in our pedals too.

Well. Maybe not for every single pedal, but most. Some wild fuzzes are better to be left without additional filtering as their features may be downsized by too stable DC source. But for non-dirt effects, the extra filtering is wanted. Looking at the filter, the idea is to place a capacitor between the supply and the ground. This will push the AC leftover ripples to the ground leaving cleaner DC voltage for the pedal. Mathematically thinking, the capacitor should be BIG to have a sufficient effect. That’s why you’ll find 1000µF and even 2200µF capacitors in some pedals.

But how does the unregulated power source affect the pedals?

Think of this like if you were powering your pedal with lab power suply that has voltage setting on a knob. Then you wiggle the voltage control between eight and ten volts as fast as you can. This will affect the operation of all your semiconductors. With fast and uncontrolled changes in operating conditions, the operational amplifiers can’t function properly. Same goes with your transistors. As supply and reference voltage changes, so change the operating conditions. And as the ripples come out at the same frequency as your wall socket pushes the AC out, you’ll have ~60Hz hum at the pedal’s output. In some extreme cases the ripple will result in even worse situations, like oscillations. But if we take one tiny 100pF cap and onebigger 220µF cap between the supply and the ground, that will send most of the inconsistencies in your DC voltage to ground.

There are a lot of different manufacturers offering their solution on how to power up your pedals. Some of those are well designed and offer very stable DC for your use. Some others.. Not so much. If your pedals sound like crap with lots of extra noises on their character, you should point your eyes to the power supply first. Even if it’s made by one of the biggest names in the business, it doesn’t mean that it will be the best choice for you and your chosen pedals. There is only one completely stable DC power source. And that’s a battery. But you can get a well regulated wall wart power supply that will serve you for 10 years easy – for the same price as you would need to spend on three batteries. Which is why i recommend using a good, regulated, stable powersource that turns the wall socket AC to the DC voltage you need.

Colorless writings, part 12 – The Preference (aka Yet Another Gear Talk episode)

Tuesday, June 24th, 2014

Are you about to tell us what pedals you use and how you chain them?

Sure. I could do that. In addition, i’m asking you readers to reveal your preferences. My comments are moderated due to vast amount of spam i’m getting even with most current protection, so don’t worry if it’ll take a day before your comment appears.. More on that later, but to be honest i’ve never spkoken with a guitarist who doesn’t have any detailed preference to his/her gear. I think we should start with the guitar itself.

I’ll begin with saying that i have rather large hands. Due to that fact the Gibson style 24,75″ scale feels awkward and cramped when i try to play anything from around 12th fret. So i settled for Fender style scale. I did think of myself as a Tele man for a long time. I’ve always thought the humble Stratocaster to be the ugliest body design there is. I had even gone to such lengths as slandering some acquaintances for their instrument of choice. Needless to say i’m no expert in field of guitars, but i’ve owned a few dozen different ones over the years. As i happened to score a japanese Fender Contemporary Stratocaster for peanuts about a year ago, i just had to try it out at rehearsals once i got it up and running (it had missing parts etc. when i got it). Took it out of a bag and played loud with it. To my massive surprise, it was the first time i could hear myself clearly through the drums and bass. That started an avalanche of enlightenment. Even with a case of slight cognitive dissoonance, i had no choice but to retract all my previous comments about the strat. Sometimes only thing that can get you forward is admitting that you are wrong. Plain wrong.

The thing is, while Telecasters sound very good to my ears, mainly because of their fast and brutal attack, the body of the sound stays very thin regardless of pickups. In terms of envelope generator curve found on synthesizers, Telecaster has very fast and powerful attack. It’s decay is just as fast leaving the sustain short and meatless too. Not to talk about release. Teles die instantly. As for Stratocasters – the attack is definitely a bit slower, but the decay time is way longer. with sustain being fat and powerful. I can come up with only one explanation for this behavior. The bridge setup. Hard tailed bridge resonates the guitar body from a tiny area resulting in Telecaster behavior. Stratocasters with standard tremolos vibrate the whole body due to springs holding the tremolo. Plus the bridge is fastened in two different positions and the mass of wood is a lot thinner under the pickups. So there you have it. Stratocaster is the most powerful sound there is. Mostly due to its tremolo bridge. I believe the power comes from the bridge, not from the body shape.

Of course, you’re preference of strings and setup affect the power too. I wonder how a Telecaster body would sound with a standard strat tremolo.

Get on with it…

Ok, i will. For guitar, i prefer Stratocaster with standard tuning, rosewood fingerboard, 10-52 set of strings and high(ish) tension for the strings by fastening the tremolo springs rather tight. For pickup i’ve grown accustomed to Seymour Duncan TB-14 Custom 5 humbucking pickup on the bridge position. It is hot enough, but not dulling hot. Plus it has very pleasing clarity and bright highs to it’s overall tone. That’s basically all that i currently need. Sure, the preference may change, but the change would need to radically alter the tone, making it a lot better before i’m going to change anything.

Next up my “production” pedal board. The board itself is made from wooden Ikea cutting board that i’ve drilled full of holes. I tend to fasten my pedals to the board with large cable ties rather than velcro. Cable ties leave the pedal bottoms with their serial number stickers in tact, which is rather important to me as a collector. Pedal arrangement is subject to change from time to time. But as active player, i’ve come accustomed to certain sounds being available. Currently my signal on the board goes like this: Guitar -> TC Electronics Polytune -> Custom made Green Ringer adaptation to FYA STF Driver in a single box -> another Custom made Green Ringer adaptation to FYA Apiformis Fuzztortion in a single box -> Nux Mod Force -> Nux Time Force -> Amp. Up octaves, OD and fuzz are the ones that get a lot of stomping. The Nuxes are there just in case i want to fool around.

What’s you’re preference for the amplifier?

About 12 years ago, i was dreaming about buying a AC30 and tried to accumulate cash for one. I always seemed to be a little short. Around those times, one local musician wanted to get himself a Fender Twin Reverb to replace a Marshall JCM800 2205. He was selling the Marshall for a low “need-to-sell-this-right-away” price. So i thought if don’t like it, i can always sell it and make a little profit in the process. But the amplifier sticked. I learned to love its sound and dynamics offered by a pair of EL34s. Later i stopped using the OD channel altogether and i’ve been on the “British clean” sound for about five years now. Sure. It has very little to do with clean, but to me, it is the greatest guitar sound there is. And we should not dismiss the fact the 2205 Marshall can handle almost any pedal at its input. All this makes it simply the perfect amplifier for me. I pair it with its original 4×12 cabinet.

To be honest. I currently have no idea how to make my sound “better”. I think i don’t even want to. This is the shit.

So.. If you read this writing all the way to here, i’d like to ask what do you, my readers, use and/or prefer? You could simply answer your guitar style, string gauges, pickup preference, pedal board setup and amplifier to the post comments.Of course it doesn’t hurt to justify your preferences too…

Colorless writings, part 11 – The Expert

Wednesday, May 28th, 2014

What now?

I felt like i needed to write this off my chest. As the title suggests i’m going to rant about these so called “experts” that think they know it all and how i think we all should use caution when we assume we have an “expert” on our hands. First of all. I’m no expert. Sure, i’ve built hundreds of effect pedals, repaired and modded a bunch of units and done some analysis on a few boxes. That does not make me an authority on the subject. I’m still learning new stuff every single day in my chosen field, which is rather narrow when compared to vast number of electronic devices designed and manufactured over the last century or so. I do not know everything and i think i never will. I do know a lot, but damned be the day when i crown myself as an “expert”.

Let’s take a look at the definition of the word. “An expert is someone widely recognized as a reliable source of technique or skill whose faculty for judging or deciding rightly, justly, or wisely is accorded authority and status by their peers or the public in a specific well-distinguished domain.” (Quote from Wikipedia).

Now, if and when someone considers him or herself as an expert, we all can judge that expert by the work we see. As the effect pedals are very narrow field when compared to anything, there are bound to be these “experts” who write books on the subject with very little real knowledge about the filed. With well done research anyone can write sufficient book on any subject. Does that make the author an expert on the matter? No. It doesn’t. What if the research part has been light and sloppy? Does the resulting work help anyone? Here’s the bigger question.

Nearly a year ago i bought a book on pedals. It was called “Practical handbook” for effects. The author had done nice research on the history of how effects came to be and there are about a hundred pedals listed with superficial descriptions. Most of the dates are fuzzed or obscured (even worse than what i do on my pedal posts) with a decade as an error margin. Granted, reliable information on certain effects is very hard to find, if not impossible. But the pretext as an introduction on the book says something peculiar. The author claims he has had about 50 effect pedals in his posession over the years. Apparently the publisher of that book considered the author to be an expert to the degree where its ok to publish his book on the subject. He doesn’t claim to be an expert de facto, but as an author of “Practical handbook” it’s rather safe to assume someone considers the author as an expert.

So you’re pissed off by someone writing a book with moderate expertise?

Almost. Think of it like this – should i write a book on raising children? I don’t have any of my own, nor i ever will, but i’ve spent some time with our bass player’s kid and even more time with my sister’s kids. So i could claim i know a few things about raising a child. But would i be any expert to write a book titled “Practical handbook” on the subject?

Other issue with the book are the technical examples. It clearly says the example schematics are not intended as a base for your own effect circuit. There is a simple reason for that. I bet they were afraid of the possible copyright issues of schematics that were completely redrawn – so they simply made every single one defunct. I could tell just by looking at the drawings – No. That won’t work. And while making the schematics are defunct, the author removed or messed up parts of the blueprints that are crucial for the function and sound of the original design. So in a sense, the technical part is completely unusable and doesn’t teach the reader anything. Needless to say i felt pretty swindled after reading the book.

Would you feel any different if the book was titled differently?

Yes i would. It should be titled “Beginner’s guide” or “Simple overview”. Then the customer buying the book would not be disappointed to these hights. There are true experts. All you need to do is log yourself in to Freestomboxes.org and start reading. You’ll notice a few screen names that offer a lot of useful information based on facts and not on guesses. It is an open forum, so there is bound to be some not so great writings as well. Still, you can learn a lot from these guys. I sure would like to read a book on pedals written by one of those gurus.

Besides. I’ve never heard them call themselves an experts.

I think the main issue here is that publisher honestly thinks guitar effects as “toys” rather than real tools of the industry. This is where i believe it all went wrong. When you don’t respect the field, how narrow it may be, you are easily tempted by selling some half ass semi-truths as facts. In full view, i’m not blaming the author, but the publisher. Putting a person with hands on experience with 50 pedals on a  pedestal as an expert isn’t probably the wisest move. I did not mean today’s colorless writing to be a book review, but i wanted to poke the issue of who gets to be celebrated as the expert. As the Wikipedia noted, the Expert needs to have accorded authorty by his or her peers. And no one should ever call a slight introduction a “Practical handbook”. As another parallel, think of a book on math called “A Practical handbook on derivation”. You come home with it and read all about how numbers came to be and how you can add one plus one. In addition it has wide range of example equations – all broken and not true. How much can you learn from broken data?

The book itself isn’t that horrible. It is a nice introduction for beginners, but as a hard fact book that offers knowledge – not so much.

Colorless writings, part 10 – The Pup

Wednesday, April 30th, 2014

This Colorless Writing episode marks one milestone for me. It is the tenth writing in the series, which also means that there are now exactly 100 (one hundred) pedal posts on this blog. Every ten pedal posts is followed with one of these. I’d like to take this opportunity to thank all of you, my readers. With around 75 page views per day, i do feel quite honoured. I’ve set up a Twitter account too, so users (and/or FB-emigraters) can easily follow my posts through that service too.

Enough with the jibber jabber. The Pup.

The pickup?

Yes. From electronic point of view, the guitar pickups are nothing more but a simple AC current source made of permanent magnets and a coil wire. In all the simplicity, the frequency of the vibrating string will be transferred to AC current. The current isn’t very high, but it usually ranges from 100 millivolts to around 1 volt. The basic idea of electric guitar is to send this low voltage AC signal to the guitar amplifier that is made of two (actually three, but the third one doesn’t apply here) parts. The preamp amplifies the guitar’s signal voltage, usually to about 12 volts and the power amp amplifies the current to the extent that the signal is strong enough to drive the speaker. Now, think about the AC current generated by the pickups. There is a huge difference between 100 mV and a full volt. The work that the preamp needs to do will be strongly affected by the level of the pickup output.

Got it. But what about the pedals? How do they react to different pickup levels?

If we look at guitar pedals from electronic point of view, we may see that most of your pedals act like preamplifiers. Bigger the signal input voltage, the less the pedal can do with it.

This is the point that flamed up the idea of writing about it. I was recently repairing a bunch of pedals and couple of the simply sounded like crap. I was pretty certain that one EHX LPB-1 Nano was broken as it sounded like overly saturated, bad sounding distortion instead of a clean boost that the circuit is – and has been since the nineteen sixties. I then decided to try it with another guitar, as the one next to my bench was Hagström F200 with original Custom 60s humbucking pickups. Took my Fender Baja Telecaster and tried the same circuits with it. Baja is from Fender’s Classic Player series and it has original Custom Shop pickups with vintage style output. First of all, i had to crank my bench amp way higher to get any sound out of it. Then i engaged the pedal.

You guessed it. Clean. No trace of the distortion. I then took the Hagström back to the equation, but lowered the volume pot setting on the guitar. Clean. So as a conclusion, the “hotter” the pickups, the less there is that a 9V operated effect can do with it. Some of you may have noticed that i’m somewhat biased when it comes to the superiority of a Tubescreamer overdrive. If you’re using it with high output pickups, it will sound horrible (cold dead hand slapping you on the top of your head), but with low, vintage output pickups the TS9 comes alive and sounds like it is supposed to. TS9 with modern high output humbuckers sucks.With vintage output singles – that’s where the magic kicks in.

There is  a chance you’ve run in to issues when you’ve tried to use some of your overdrive pedals with your  synth or keyboard. The signal pushed by those instruments are usually at line level, meaning that the AC signal voltage is closer to five volts. It is a rare pedal that can operate well with that kind of signal without becoming choked sounding. No. It is not a fault in the pedal, but simply a feature. But there is a simple workaround for these situations. Just build yourself a simple, passive volume control in a mini box and use it to bring the synth’s signal down before pushing it to the pedal. You can always push it back up to line level with something like MXR Microamp if you need to get the signal back to your synth.

But you’ve written before that all the pieces of the gear puzzle affect each other? Isn’t that the same thing that applies here?

Partially yes. Some pickups won’t play nice with some pedals. So if you check youtube demos for the unit you are interested and buy the pedal based on that information, there is always a chance that the unit won’t sound even remotely the same with your gear. With high gain distortions the issue isn’t that big. Mainly because anything that goes in comes out totally scrambled. But how about creating a mild overdrive pedal that works and sound great on any pickup configuration? Now that’s not as simple as one might think. And what about active pickups? In essence the active pickups simply mean that there is impedance changing preamp built insinde the pickup. Sometimes those preamps boost the signal too. If you don’t have experience with active pups and a Tubescreamer, you can imagine what that will sound like. That would be pretty much the same thing as you were driving your TS with a Super Hard-On. True, hot (as in high output) pickups tend to sound bigger and better. But some pedals may not reach their full potential with those pickups.

Is it better to have vintage, low output pickups than modern, high gain output ones?

You tell me. Former is definitely the way to go if you want to use your Tubescreamer as the main overdrive. But once again, we would need to define “better” before jumping to any conclusions. Big, fat heavy metal mush sound  isn’t going to be happening with vintage output pickups. There are tons of different sounding pickups out there. Which ones work for you and your pedal rig? I guess you’ll just need to try a few sets out to find it out.

Colorless writings, part 9 – The Switcheroo

Monday, March 31st, 2014

Back on the subject of bypass switching are we?

Partially yes. But i think i’d like to say thing or two more about switches in general. Actually. I was sitting on my desk that i use as work bench and killing myself with a build. That’s when the title of today’s Colorless Writings came to me.

As i personally hand-wire everything in my builds, i only use switches with solder lugs. In the time i’ve built and repaired pedals, i must have soldered on way more than 600 switches altogether by today. At first, these mechanical components seem solid. But if you take a closer look of how those are made, you might convince yourself that the first impression isn’t as accurate as you thought.The pins/lugs are held in with plastic housing. Now, those may seem sturdy enough, but when you’re soldering your wires to those lugs and apply just a little too much heat and pressure, you can see and feel the lug moving. Once the lug moves a fraction of a millimetre, the structural integrity is compromised. In a sense, those components are probably the most fragile thing in any build. I don’t want to think how many semiconductors i’ve soldered on in all this time, but never burned any transistors by accident (yet). But have i burned switches? Many. And if we count the ones that have landed back on my desk with them becoming faulty after six months of use, there are a few more. Someone on the mighty interwebs said that firm, decisive and quick is the way to go with all the switches. I couldn’t agree more.

How do the switches work?

The most common toggle and stomp switches we use for pedals are SPST, SPDT, DPDT and 3PDT (of course there are others as well…). Next you might ask what do these initialisms mean. Well:

  • SPST – Single Pole Single Throw
  • SPDT – Single Pole Double Throw
  • DPDT – Dual Pole Double Throw
  • 3PDT – Triple Pole Double Throw

As you might have guessed, the SP/DP/3P part means how many vertical poles the switch has. The second part tells us the effective “throws”, or positions. This may be a bit misleading, since there are different ways the toggle connects the lugs. First, the SPST has only two lugs. The other position has these two lugs connected and the other has them apart. Simple, right? But then we get to the SPDT which has three lugs. There are two different toggle types of this switch. On-On and On-Off-On. Meaning that there’s actually three effective throws on the On-Off-On switch. One position connects the middle lug to the upper lug, other connects the middle lug to the lower lug. Middle position connects nothing to nothing. The DPDT has six lugs and those work exactly like the lugs on the SPDT, except that there are two vertical poles that both respond to the same flick of that switch. Same thing with 3PDT. The nine lugs represent three different poles that all connect or disconnect the same way as SPDT. There are just three of those vertical poles connecting and disconnecting at the same time. 4PDT has four poles, but those too act in the same way. Different poles can be used to connect and disconnect different things on a circuit – for a single flick. I’ve drawn a memory guide for myself a long time ago. It also includes the pot lug numbering convention that i’ve adopted for my use.

Other types of switches you might find on a pedal are tactile or momentary switches, rotary switches and possibly On-On-On types.

The tactile and or momentary switches are very common and usually used in electronic bypass switching circuitry. These come usually in two different configurations. Namely NO and NC. These mean that there is always only one “pole” that is either connected or unconnected when the button isn’t pressed. NO is short for Normally Open (not connected) and NC is short for Normally Closed (connected). Now, when you push a button that is NO, the connection is made for the time you are pushing the button. Once you release your hold, the connection is gone. Momentary switches come in all the variation of different numbers of poles with usual On-On configuration. I haven’t seen this kind of switches on pedals, since the circuitry behind the 3PDT momentary switch is usually complex – unless it is used for momentary feedback or mute control.

The rotary switches are fun. These come in many, many different configurations. For example, 2P6T and 4P12T. First part of the type “code” is for the number of poles. Usual number of poles are one, two and four. Second part tells us how many positions the pole can have. 6T is for six turns and 12T is for 12 turns. Common boutique use for these switches is to place different cap values or different clipping diode arrangements on the turns. For the cap value switching, the simplest example would be the good ‘ol Rangemaster with 1P6T switch. On that configuration, the input of the circuit should be placed on the middle pin. Then the board should have six different values for the input cap. Let’s say 4n7, 10n, 22n, 47n, 120n and 470n. All those caps need to have the other lead at the transistor’s base, while the other leads connect to the six lugs on the switch. This way the Rangemaster can be used from treble booster to bassy wide range booster and everything in the middle. There are, of course, numerous different pole and turn variations of these switches available.

The one type that’s quite rarely used in a pedal is the DPDT On-On-On switch. There are exceptions. You may have come across one of these switches in your time. Most Les Pauls, SGs, 335s and basically any of the guitars with two humbuckers have this type of switch for the pickup selector. The up and down settings work exactly like in On-On switch, but the middle position is different. While down position connects middle lugs to the upper lugs and up position connects the middle lugs to lower lugs, the middle position has fthe first pole’s middle lug connected to upper lug and the second pole’s middle lug is connected to lower lug. This gives out even more switching options than the previous types.

Colorless writings, part 8 – Short but sweet

Wednesday, March 5th, 2014

I’ve been wanting to write this piece for a long time. As a note to self (and to you, too)…

These are just guitar effect pedals. They are not magic. Capacitance is capacitance and resistance is resistance. One component won’t sound any different from another with exactly the same value in capacitance or resistance. They are not magic. The thing called “mojo” is just a psychosis. It doesn’t exist. These are just guitar effect pedals.

Colorless writings, part 7 – The Collector value

Monday, February 3rd, 2014

So you’re talking about the prices of used, collectible units?

Yes i am. This is one subject that shows human nature at it’s finest. Let’s make up a person. We’ll call him Peter. Peter was playing a guitar actively in early to mid 90’s. He had all the right gear back then. The gear that was cheap with reasonable sounds and was underestimated by many at the time. His pedals were used a lot, and none of them survived without any nicks and scratches.

Twenty years go by faster than one expected. Peter now has a day job and he’s given up on his rock star dreams. He only has one Les Paul left and trusty old 15W tube combo that he plays every now and then. usually after a few beers. The pedals he used to play are lying in a cardboard box at the back of his garage. One day he remembers the box and decides to put all the old trusty pedals for sale. All the great oldies, like DOD FX50B Overdrive Plus and FX80B Compressor, both with missing battery doors, Ibanez soundtanks DL5 Delay and TS5 Tubescreamer, Boss DS-1 Distortion, Marshall Guv’nor (obviously without a battery door) and MXR Phase45 with missing pot knob.

Now. What do you think happens next?

What?

The sites that list used guitar gear get filled with posts selling these items. Peter clearly doesn’t have any clue what the units sell for, as he currently isn’t into pedals. Hasn’t been for over twenty years, even then he was more of an average user than enthusiast. And of course, as the units are all “old”, there must be some good money in them. This is where it all goes straight to hell. Peter can’t understand why all the other site users slam him down on comment threads and why no one is buying the pedals.

So he just put in too high prices?

Yes. As i keep on hunting and dealing with pedals every day, i run into this thing almost every day. For some reason almost everyone without deeper enthusiasm thinks that everything must be valuable just because it has ten or twenty years of age. And that’s why we see all the most common late 80’s and 90’s pedals for sale with ridiculous price tags. These people log on to eBay and search for their item. Then they estimate the value based on those units that people (thousand other Peters from around the world) are already asking way too much. The next Peter then gets the idea that every one of those is valuable. As the end result, there are now 15 pieces of beaten DOD FX50Bs with missing battery doors available, all for $100 a piece plus shipping. And none of those are selling. Gee. I wonder why.

Let’s make up another character and call him Mike. Now. Mike has similar situation, but his pedals from early to mid 90’s are slightly more desirable. Let’s say his cardboard box holds a DOD FX13 Gonkulator Modulator, Ibanez FL9 Flanger and a MXR Distortion+ from 1976, all three in very good condition.

Mike has a better view on how the world works. He could use a little cash to help his new hobby with miniature airplane models. He’s heard of the site called effectsfreak.com and he logs on to see what his units usually sell for. He then sets the starting price at slightly lower, let’s say 5 bucks than for what the units have sold for in the past. He’ll get all the units sold in first two days. He’ll make a nice profit and also one happy collector per item.

There should be more Mikes in the world.

The idea of your unit being extremely valuable may come from the facts that you’ve seen really old and rare pedals from the 60’s, 70’s and early 80’s sell for hundreds, maybe even as high as a thousand USD. But something inside a human mind won’t accept that those are not the same thing as the units you have, the units that cost next to nothing as new and there are 25 000 pieces of them manufactured and spread around the world. Further, those are not worth anything when they are missing knobs, bottom plates, battery doors etc. This is another cold hard fact that people seem to be forgetting. One should try to sell one of those units with missing parts to any brick and mortar musical instrument store. You can guess the answer you’ll get.

How is it wrong to ask for some amount if someone is willing to pay what the seller is asking?

It may not be wrong. But i see this behaviour every single day and i totally see the sellers getting slammed in the comment threads. The thing i can’t emphasize enough is “don’t be a dick”. I’ve been on the brink of ripping someone off on some deals and i’ve always felt bad afterwards. When dealing with used gear that is more or less subject to its magical qualities, i strongly believe that it’s best to have both parties being ok with the end result. Sure. I’ve bought shit with a hefty price tag and i’ve been a subject of very bad deals. Probably even been a cause for one or two. Life is just a game that we must learn to play along the way. Being a dick makes it difficult for all of us.

The problem get even deeper when someone really pays the unreasonable price that was asked for a common unit. That just raises the price of that model artificially without any basis for it. We have the internet nowadays. One can easily get a clue what the unit is really worth by just doing a minute worth of footwork.

I may sound like a dick here too. That’s not my intention. My intention is to let you, the reader of my puny blog, know that you should not pay good money for unit that is missing rubbers from the bottom, the bottom plate, the serial number, pot knobs, battery door or anything else. These units are not collectible and their place is in rather the trash bin than on the auction listings with massive price tags. So dear god, the missing battery door is not something that should only shave off 3% from the price of a counterpart in mint condition.

Colorless writings, part 6 – The Diode Breakdown

Thursday, January 9th, 2014

What on earth are you talking about this time?

Doesn’t the title say it all? Ok, ok. I admit it’s somewhat ambiguous. I’ll start by talking about the diodes in general and you just try to hang on. Is that ok? Good.
Most of you know the basic use of diodes in stompboxes. First one everyone has encountered is definitely the bright red LED that lit up when your first guitar effect pedal was first engaged. The LED is a diode as much as all the other diodes are diodes. As the name Di-ode suggests, there are two terminals to every diode. If there were more, it would not be a diode anymore. It would be a triode or pentode and so on. At simplest, the diode will pass the current and/or voltage from one terminal to the other, but not the other way around. Most of you have played with an overdrive or distortion type of pedal? I know you have. The common way to create distortion is to use back to back diodes to make the signal clip, as in distort. Other very common use for diodes in guitar effect pedals is to use them for polarity protection. This use has two different applications. In series and in parallel. The diodes are also commonly used in electronic switching as rectifiers for switching JFETs. And then, of course, there’s the humble indicator LED. These must be the most common uses for diodes. While there are some applications for zener diodes to lower the voltage and a few others, the ones listed above are the most common.

The diode is simple semiconductor that is based on the idea of semiconducting material passing the voltage and current only in one direction. When someone had the eureka moment of placing two in parallel and in opposite direction of each other, the world changed. Earlier we had to rely on transistors driving each other to get the dirt out of our electronic guitar addons. After that moment we started having lots of harmonic distortion with ease.

All of the diodes used for clipping have their own character to the clipping. The most usual 1N914/1N4148 (or any other similar Si diode) has the tight feel on the breakage. Other commonly used clipper diodes are 3mm LEDs, germanium diodes, other small signal diodes like 1N60P and schottkys. LEDs compress the signal more and offer more output level. Schottkys are quite similar in character, but slightly tighter and more bassy. Germaniums tend to offer softer sounds to the clipping, but they drop the level a lot more than any other type. Different germanium diodes also have slightly different responses, but they all share the level issue. 1N60Ps are close to 1N4148, but they sound more brittle and glassy.

Some of you weren’t probably aware that any transistor can also be used as a diode? Just omit, snip or maim the collector and use the base as an anode and emitter as a cathode. Same thing applies to FETs as well. The current will pass from base/gate to emitter/source, but not the other way around.

So that’s for the clipping configuration, how about other purposes?

From the common ones, the one that’s simply more important than indicator LED to me is the reverse polarity protection. To protect the circuit from wrong power supplies, engineers have used diodes to rectify the supply voltage. There are two common, yet completely different ways to achieve this. This protection is very good thing to have, as some amplifying semiconductors are very delicate devices. Meaning that they will burn up in seconds if they get + voltage to where – should be and vice versa.

First, these is the method of placing a diode anode to ground and cathode to supply. This method has a valid point, as it doesn’t touch the voltage at all. But as a huge downside, the wrong polarity causes the diode to be only thing between positive and negative lead of the supply. Meaning that all the possible current that the supply is capable of giving out is shorted through that diode, leading it to literally break down. If there happens to be a fresh 9V battery as a supply, all the juice is pushed through that diode in just a few seconds. In worst case, the diode practically explodes and takes a chunk of the board with it. In best case the silicon semiconductor just burns up leaving the diode to act as a sort-of resistor. Either way, the effect will be completely fried if it gets the wrong polarity as its power supply. Sure it can be fixed, but it’ll need at least wire cutters (preferably an solder iron and a new diode) to get it running again. Unless the board is done for. Sadly, i’ve seen those cases too.

The second method isn’t as popular in main stream big brand designs as it is for boutiquers and small brands. This is to take the diode in series with the supply. Yes. It’ll affect the supply voltage. In worst cases, when using a diode that isn’t meant for this application, the voltage drop could be a Volt. That is usually way too much of a drop, so using a proper diode is more than crucial. 1N5817 Schottky is one of the good ones. The drop stays low and as with any diode using this method – the board or the diode itself doesn’t get hurt if it gets the wrong polarity. Circuit simply won’t work at all. In other words, a diode in series with the supply will eliminate all current flow from the circuit without breaking anything up.

 What about LEDs and the other types then?

The indicator LEDs are diodes just like their other counterparts. The just happen to emit light when current passes through them. Thus the name, Light Emitting Diode.

By other types in this context, i mean zener diodes in particular as those are the ones we commonly find in pedals. In addition to small signal diodes, schottkys and LEDs. Zeners have one very nice feature. They can be used to lower the voltage. In simplest terms, placed in parallel with the supply (anode to ground, cathode to supply), the supply voltage will be reduced to the value of the zener diode. If you use 8.2V zener in that position, the excess voltage will get dissipated through the diode, leaving the supply at 8.2 volts.

I feel like i haven’t even started on this diode subject, but the usual 1000 words are already up. So, against my standard behaviour, i’m going to leave you with a wikipedia link that explains more than you ever need to know about diodes. In detail.