Noise is a demon that plagues all high gain distortion pedals. It's a fact of life that there's just no escape from... or is there?
Before we begin lets take a moment to define the word 'noise' as we use it in this article. When we use the word noise we're referring to the hum & hiss you hear when you are not playing. The moment you strike a note, the noise is 'gone', but in reality it is simply overcome by the note having been played. The note is passing trough the distortion circuit and being amplified in the same way the noise is, but being that the note is intentional and, as such, a much louder source than whatever is causing the noise in the first place. As the struck note decays the noise slowly becomes more apparent until it overcomes the decaying note, as the noise never left, it was simply overpowered by the note.
Why are distortion pedals noisy?
Many distortions use cascading gain stages to create their sound. While this creates some great distorted tones, each gain stage also amplifies all background noise.
Not all distortion pedals use this design, but the long and short of it is that a distortion pedal will amplify and distort any signal it is fed; even if you can not hear the noise causing signal source before activating the pedal.
What could be causing the noise?
Many times, the noise accentuated by distortion pedals can be tracked to environmental issues. This is why professional recording studios are so expensive to design and construct. Painstaking measures are taken to ensure that every power source is pristine, ever power line is shielded and kept far from physical audio paths, all of the walls are shielded against stray radio frequencies, and so on.
That being said; let's take a quick look at what might be causing your noise and a few things you can do to clean up your signal.
Power
The first thing to look at is how you're powering the unit. Batteries will deliver a quieter performance, as they are not subject to some of the issues that affect AC power, but they have a downside as well. Batteries will steal your tone as they die, at such a subtle rate, you might not notice until your tone is truly not the same anymore.
AC power eliminates the gradual tone theft caused by dying batteries but they open the door to other noise causing possibilities. AC power directly from the wall is wrought with noise. The power is not delivered in a conditioned or filtered manner which is perfectly acceptable for most worldly applications, but not in the audio realm. If you rely heavily on pedals of any kind to create your tone, we highly recommend investing in a good power supply for them. Here in our shop we use the PA9 power supply from Godlyke, but there are many others on the market.
Another power distribution possibility could be that you have too many pedals on your power supply's chain. Noise occurs when you overload your power supply's capacity. The rated output of your power supply might indicate it can handle 4 or 5 pedals (after doing the math of course), and in fact it can- it just can't handle it well. That output rate is there to tell you where the failure point would be, not where the optimum operating level is. To keep your pedal board sounding clean stay well under your power supply's rated output. Some pros suggest you cut the rated output in halve and use that as your load guide. I say use your ears. If you hear degradation, even while within the specs of your power supply, ease back on its load.
Cables
Why are you plugging your $1000 guitar into your $1500 amp with a $9 cable? And DO NOT get me started on those $3 patch cables you're using in between each pedal on your board. C'mon guys... your cables are essential to your tone, so skimp someplace else.
Our good friend Mark Stoddard over at Lava Cable chimes in with this angle:
"Noise or microphonics is caused by cable movement or contact as small voltages are generated from this that interrupt the signal path. If the cable does not have the correct amount or type shielding the noise will be greater. Also, the lower in capacitance a cable is, the easier the noise will be heard as more signal is passed. Typically, with static cable such as pedal jumpers noise is not an issue as there's no movement. It's important for cable jumpers to be solidly built as a loose solder connection or loose solder-free connection can cause noise when the pedal or cable is moved."
This is good info, lets expand on it a bit- pedal jumpers or patch cables actually take some serious abuse if you're a heavy footed pedal user. Every time you're stepping on the switch you're causing that whole unit it shift, unless your using mounting screws to keep your pedals on your board, and that slight shift with each stomp causes your patch cables to move and flex as well. So each time you engage your boost pedal for a solo, lets say once per song multiplied by 10 songs a set, thats 20 stomps... that can add up to some sizable movement over the course of the evening, not to mention the movment your cable plugging your axe into your pedal board is seeing. So you want to be sure that these are well constructed.
The other topic Mark touched on is capacitance. Over at Lava Cables web site they have a great write up on capacitance, and cables in general, I encourage you to check it out. But in a nut shell, capacitance sucks the high end out of your signal. The longer the cable the higher the capacitance, which is why 40 foot cables sound dark and muddy. So, stick to the correct cable length. If you're a bedroom rocker, a couple of 5-8 foot cables is probably all you need. If you're gigging try 12-15 footers, they'll probably do you well for most venues.
Shielding
Do you have any quiet spots in the room you currently play in? Meaning- if you move around in the room do you have spots that are less noisy? If you do that tells us you've got something floating around in the air which might be quieted by shielding your guitars cavities.
Shielding the cavities of your guitar is not all that difficult, it can be time consuming, but not hard; however, the end results can be amazing. What shielding does is it prevents radio frequencies and other 'noise' from entering your pick ups. The shielding doesn't make the 'noise' signals bounce away, it actually absorbs the noise. The conductive material in the cavities attracts the signal and sends it to ground rather than letting it float around your pick ups. There are a lot of different methods to shield your guitar, so do your research. You can probably start and stop at GuitarNuts.com. GuitarNuts has been offering tips and guidance for shielding and pickup re-wiring for years, and they're a great resource. I've rewired more than my fair share of instruments using their diagrams, check them out!
Pedal board config
Heres a real example from a customer that had horrible noise issues with his Body Rot II. His pedal signal chain was a GE7 EQ to 'scoop' his tone, then running into the Body Rot II, then some reverb and delay. Here is exactly what I told him via Email:
One thing I would recommend right off the bat- put the GE7 at the end of your chain (before your delay or reverb) to sculpt your entire tone. If not at the end, certainly after the BRII. Essentially the BRII will take the boosted signals produced by the GE7 and distort it. Causing noise when there otherwise not be any.
With the tone 'scooped' by the EQ, the highs are boosted, then feeding those boosted highs into the BR2 to further boost and distort, caused hellacious noise. Simply moving the EQ cured his problems.
Another common noise causing problem the fact we use the volume knob on our distortion pedals as a master volume. Yes its handier to use the volume control on your pedal to turn your amp up and down, but its causing more noise than you need to hear. Let the amp do the heavy lifting. Set your pedals volume to the same level on or off (unity gain-ish) and use your amp to give you more volume when you need it, this will clean you up greatly.
The obvious
Do you have any computer monitors in the room- the older big monitors, not a flat panel? If so, you're probably going to get noise.
Any fluorescent lighting in the room, either overhead or on a wall? If so, you're probably going to get noise. Even the new compact fluorescent bulbs that are going to be the only types of bulb we can buy in the near future are noisy. The best cure for both the old monitor noise and the fluorescent light noise is to shield your guitar, but even the best of shielding can't eliminate the noise those sources cause.
One last thought- noise gates are always useful in high gain situation. Sometimes there's just no way around them.
Dennis M.
Dennis Mollan is the founder of Pro Tone Pedals. With 20 years experience as a practicing guitarist coupled with his formal education in music theory and audio engineering Dennis has become a noted resource in all things rock guitar related. Pro Tone Pedals was founded in 2004 to provide hand built high quality guitar effects to modern hard rock guitarists. In the five years following, the Dallas Texas based company has had the opportunity to work with some of the biggest names in modern rock music.
Pro Tone Pedals have been on tour and in the studio with Velvet Revolver, Alice In Chains, Camp Freddy, Flickerstick, Ministry, Peter Murphy, Rusty Cooley, Richie Kotzen, Jeff Loomis, Nevermore, Prong, Mission UK, Poison, Overkill, Fear Factory, Mob research, and the Cult.
Website: http://www.ProTonePedals.com
Blog http://blog.ProTonePedals.com
Article Source: http://EzineArticles.com/?expert=Dennis_Mollan
Showing posts with label Plexi. Show all posts
Showing posts with label Plexi. Show all posts
Thursday, 5 November 2009
Friday, 23 October 2009
Make your own Tube amp, book review
This article is a book review on a series of six books that is the most comprehensive and lucid explanation of guitar tube amp architecture, circuits, tone, components and construction technique for DIYers I have ever found. The review deals with each book separately and recommends purchasing them in a specific order to grow your knowledge in step with your building experience.
Kevin O'Connor of London Power has created a series of books under the main title of "The Ultimate Tone." These books are truly unique and carefully tailored for the Do-It-Yourself (DIY) guitar tube amp hobbyist and boutique amplifier builder. The books have a home-made 'feel' as well... all the illustrations are done by hand and the books are photocopy-printed on 8.5″x11″ paper and bound with plastic spines and clear plastic covers. There are six books in the series now with the most recent being released in the late spring of 2008. You may want to buy the entire series all at once and get a modest savings, but I think you should consider buying them one at a time and digest as you go, building projects along the way. A key point though... you don't necessarily want to buy them in numerical order. I recommend the following sequence:
The Ultimate Tone Volume 3 - Generations of Tone
The Ultimate Tone Volume 5 - Tone Capture
The Ultimate Tone Volume 2 - Systems Approach to Stage Sound Nirvana
The Ultimate Tone Volume 4 - Advanced Techniques for Modern Guitar Amp Design
The Ultimate Tone - Modifying and Custom Building Tube Guitar Amps
The Ultimate Tone Volume 6 - Timeless Tone Built for the Future Today
The Ultimate Tone Volume 3 - Generations of Tone
This is the most important book in the series for the beginning tube amp builder.
Chapters 2 through 4 lay down the foundation of good DIY tube amp construction, filling you in on good electrical connections, grounding technique, lead dress and other wiring techniques, and mechanical layout including assembly methods like terminal strips, turret and eyelet boards.
The subsequent chapters each pick a particular 'iconic' amplifier, each iconic amplifier being a prototypical example of amplifiers of its class, and they are examined in detail as to the circuit topology, peculiar tonal characteristics that result and fatal flaws that the product is notorious for. Kevin provides the original schematics and then shows how you can apply the techniques detailed in the earlier chapters to improve the performance and reliability of the icon without harming the tone. The schematics are redrawn, layouts are provided and mechanical solutions are worked out to make each chapter a complete, self-contained, build-it-yourself amp project.
This process is repeated for several variations of the Champ in chapter 5 (this chapter greatly influenced my own single-ended amp project), then in quick succession: the Bassman, Plexi, 800, Bull Dog, AC-30, Portaflex, SVT, Bass Master, Custom Special, Guitar Mate, Herzog and Laney amplifiers are dealt with.
If you can only buy one book for your DIY guitar amp hobby I'd heartily recommend this one.
The Ultimate Tone Volume 5 - Tone Capture
Volume 5 picks up where Volume 3 left off, with a project-oriented approach and some sophisticated DIY tube amp solutions for guitar and bass.
The book starts off with a chapter overviewing vacuum tube operation called 'tube tone,' followed up by a chapter on guitar electronics and pickup characteristics.
The next two chapters are small projects: Sigma for effects switching and Triple-X for amplifier switching.
Chapters 5 & 6 are on transformers... important components but it made me yawn, sorry.
Starting with chapter 7, all the stops are pulled out and you are in project heaven... Major (200W), Soma 84 (EL84 amp), Standard (the London Power Standard Preamp from 1995 coupled to a 50W amp using four power tubes), Doppelsonde (mixing power tube types), AX84 (discussion on the original goal of a very low output power amp), Kelly (50W from 4 6V6s), and several other projects of lesser scope.
One favorite project I did was based on Kevin's reworking of the HotBox tube preamp pedal from Matchless in chapter 16. I built this pedal in a truly "true point-to-point style" (meaning terminal strips) in a tube pedal enclosure from Doug Hoffman, substituting a Baxandall tone stack and reworking the preamp values to be more Dumble-esqe (non-HRM type).
What would you do to match an amplifier to Yngwie Malmsteen's style? See chapter 18, 'Swede.'
The Ultimate Tone Volume 2 - Systems Approach to Stage Sound Nirvana
Volume 2 is not project oriented. The bulk of the book, chapters 2 through 5, deals with power supply tricks and a comprehensive overview of power amplifiers, including tube, solid-state and hybrid power amps. Chapter 3, on tube power amplifiers, has some very practical information on mods and fixes to Marshall and Fender bias circuits.
I like the 1st and last chapters of Volume 2 the best. The first chapter is a short discussion of sound stages and how you might setup your gear on stage for the best audience/band experience. The last, chapter 6, is called "Pillars of Tone" and in this chapter the major contributors tone at the block-level of a guitar tube amplifier system design are discussed one by one and Kevin provides some very valuable insight into tone shaping throughout the preamp/amplifier.
The Ultimate Tone Volume 4 - Advanced Techniques for Modern Guitar Amp Design
This is the book you'll want to buy if you feel the need to get deeply involved with the power scaling technology that Kevin has developed. Power Scaling, coined and trademarked by Kevin, is the way you can get aspects of power amp distortion (as opposed to preamp distortion) into your tone at bedroom volume levels. Volume 4 is not DIY project oriented but explores the issues, including attenuation, power scaling (both down and up), sag, and power management, tackled by modern guitar tube amp designers.
That said, the second-to-last chapter in Volume 4 might be important for a broader group of enthusiast builders... design philosophy. In this chapter Kevin provides a hierarchical design process that could be used to make key decisions on how you approach your next project.
The Ultimate Tone - Modifying and Custom Building Tube Guitar Amps
There is no volume number in the title of this book, it was the 1st. Personally, I bought it for completeness. I specifically wanted to have the 'perfect effects loop' information, although the loop itself is incorporated into a project in Volume 5. TUT also has some excellent material on reverbs and signal switching methods that is not explained in the other volumes. The first half of TUT introduces/overviews tube amp systems, power supplies & grounds then focuses on preamp and power amp modifications to commercial amplifiers (e.g. Marshall / Fender)... if you are totally new to tube electronics you may want to buy this 1st volume at the same time as Volume 3.
The Ultimate Tone Volume 6 - Timeless Tone Built for the Future Today
In many ways, Volume 6 is a continuation and extension of the material in Volume 4, where Power Scaling is introduced. In Volume 6 a new 'direct control' version of Powerscaling is featured which was introduced in Vol 4 but flushed out with comprehensive circuits and applied to 'sag' and sustain control as well in Vol 6. The new scaling circuits have many advantages for a DIY builder like greater noise immunity and less sensitivity to layout, etc.
I applied the new DC Power Scaling to a Trainwreck clone project and was really impressed with the improvement in 'playability' at lower volumes... the unmodified Trainwreck Express circuit is just too loud for domestic use, needing to be cranked to get the sweet tones it is renowned for.
One of the chapters in Volume 6 is dedicated to the Dumble amplifiers... something I was really looking forward to since many of my hobby projects focus on those circuits. I found this short chapter to be a good introduction to the overall architecture of the Dumble amps, written from the point of view of the evolution from the early modified standard amps that Alexander Dumble started out doing, but I felt the chapter fell short in discussing some of the more important subtleties of the later Dumble models.
Volume 6 also has lots of other material in it, including a great tutorial on designing really high output power amplifiers and a great chapter on high gain amplifier designs with real-world circuits referenced and detailed.
In Summary...
Kevin's books have a very empirical approach. He encourages you to set aside convention in some instances or not be afraid to try combinations of tubes or even pulling tubes and in all cases clearly explains why it is o.k. and points out any reasons why it wouldn't be o.k. All the examples in the books are very practical and he certainly has the DIYer in mind as he is writing.
Kevin's body of work is truly encyclopedic in nature, and considering that, one feature sorely lacking from his books is any kind of indexing... this is aggravated by the fact that Kevin constantly refers to previous writings rather than repeat himself in a new volume, and it is very difficult to put your finger on the reference even with the other book in hand. Perhaps search engine technology, like Google's ability to search protected content, could be put to good use in this case and provide a kind of 'auto-index' on the web of all of Kevin's books without actually giving away the book itself. Or better yet, how about an e-book format of Kevin's entire collection of TUT books... I think all of the e-book readers include searching capabilities... and Kevin's hand-drawn schematics would probably scale adequately and be very readable on the e-paper displays these devices feature.
Article Source: http://EzineArticles.com/?expert=Mark_Douglas_Roberts
Kevin O'Connor of London Power has created a series of books under the main title of "The Ultimate Tone." These books are truly unique and carefully tailored for the Do-It-Yourself (DIY) guitar tube amp hobbyist and boutique amplifier builder. The books have a home-made 'feel' as well... all the illustrations are done by hand and the books are photocopy-printed on 8.5″x11″ paper and bound with plastic spines and clear plastic covers. There are six books in the series now with the most recent being released in the late spring of 2008. You may want to buy the entire series all at once and get a modest savings, but I think you should consider buying them one at a time and digest as you go, building projects along the way. A key point though... you don't necessarily want to buy them in numerical order. I recommend the following sequence:
The Ultimate Tone Volume 3 - Generations of Tone
The Ultimate Tone Volume 5 - Tone Capture
The Ultimate Tone Volume 2 - Systems Approach to Stage Sound Nirvana
The Ultimate Tone Volume 4 - Advanced Techniques for Modern Guitar Amp Design
The Ultimate Tone - Modifying and Custom Building Tube Guitar Amps
The Ultimate Tone Volume 6 - Timeless Tone Built for the Future Today
The Ultimate Tone Volume 3 - Generations of Tone
This is the most important book in the series for the beginning tube amp builder.
Chapters 2 through 4 lay down the foundation of good DIY tube amp construction, filling you in on good electrical connections, grounding technique, lead dress and other wiring techniques, and mechanical layout including assembly methods like terminal strips, turret and eyelet boards.
The subsequent chapters each pick a particular 'iconic' amplifier, each iconic amplifier being a prototypical example of amplifiers of its class, and they are examined in detail as to the circuit topology, peculiar tonal characteristics that result and fatal flaws that the product is notorious for. Kevin provides the original schematics and then shows how you can apply the techniques detailed in the earlier chapters to improve the performance and reliability of the icon without harming the tone. The schematics are redrawn, layouts are provided and mechanical solutions are worked out to make each chapter a complete, self-contained, build-it-yourself amp project.
This process is repeated for several variations of the Champ in chapter 5 (this chapter greatly influenced my own single-ended amp project), then in quick succession: the Bassman, Plexi, 800, Bull Dog, AC-30, Portaflex, SVT, Bass Master, Custom Special, Guitar Mate, Herzog and Laney amplifiers are dealt with.
If you can only buy one book for your DIY guitar amp hobby I'd heartily recommend this one.
The Ultimate Tone Volume 5 - Tone Capture
Volume 5 picks up where Volume 3 left off, with a project-oriented approach and some sophisticated DIY tube amp solutions for guitar and bass.
The book starts off with a chapter overviewing vacuum tube operation called 'tube tone,' followed up by a chapter on guitar electronics and pickup characteristics.
The next two chapters are small projects: Sigma for effects switching and Triple-X for amplifier switching.
Chapters 5 & 6 are on transformers... important components but it made me yawn, sorry.
Starting with chapter 7, all the stops are pulled out and you are in project heaven... Major (200W), Soma 84 (EL84 amp), Standard (the London Power Standard Preamp from 1995 coupled to a 50W amp using four power tubes), Doppelsonde (mixing power tube types), AX84 (discussion on the original goal of a very low output power amp), Kelly (50W from 4 6V6s), and several other projects of lesser scope.
One favorite project I did was based on Kevin's reworking of the HotBox tube preamp pedal from Matchless in chapter 16. I built this pedal in a truly "true point-to-point style" (meaning terminal strips) in a tube pedal enclosure from Doug Hoffman, substituting a Baxandall tone stack and reworking the preamp values to be more Dumble-esqe (non-HRM type).
What would you do to match an amplifier to Yngwie Malmsteen's style? See chapter 18, 'Swede.'
The Ultimate Tone Volume 2 - Systems Approach to Stage Sound Nirvana
Volume 2 is not project oriented. The bulk of the book, chapters 2 through 5, deals with power supply tricks and a comprehensive overview of power amplifiers, including tube, solid-state and hybrid power amps. Chapter 3, on tube power amplifiers, has some very practical information on mods and fixes to Marshall and Fender bias circuits.
I like the 1st and last chapters of Volume 2 the best. The first chapter is a short discussion of sound stages and how you might setup your gear on stage for the best audience/band experience. The last, chapter 6, is called "Pillars of Tone" and in this chapter the major contributors tone at the block-level of a guitar tube amplifier system design are discussed one by one and Kevin provides some very valuable insight into tone shaping throughout the preamp/amplifier.
The Ultimate Tone Volume 4 - Advanced Techniques for Modern Guitar Amp Design
This is the book you'll want to buy if you feel the need to get deeply involved with the power scaling technology that Kevin has developed. Power Scaling, coined and trademarked by Kevin, is the way you can get aspects of power amp distortion (as opposed to preamp distortion) into your tone at bedroom volume levels. Volume 4 is not DIY project oriented but explores the issues, including attenuation, power scaling (both down and up), sag, and power management, tackled by modern guitar tube amp designers.
That said, the second-to-last chapter in Volume 4 might be important for a broader group of enthusiast builders... design philosophy. In this chapter Kevin provides a hierarchical design process that could be used to make key decisions on how you approach your next project.
The Ultimate Tone - Modifying and Custom Building Tube Guitar Amps
There is no volume number in the title of this book, it was the 1st. Personally, I bought it for completeness. I specifically wanted to have the 'perfect effects loop' information, although the loop itself is incorporated into a project in Volume 5. TUT also has some excellent material on reverbs and signal switching methods that is not explained in the other volumes. The first half of TUT introduces/overviews tube amp systems, power supplies & grounds then focuses on preamp and power amp modifications to commercial amplifiers (e.g. Marshall / Fender)... if you are totally new to tube electronics you may want to buy this 1st volume at the same time as Volume 3.
The Ultimate Tone Volume 6 - Timeless Tone Built for the Future Today
In many ways, Volume 6 is a continuation and extension of the material in Volume 4, where Power Scaling is introduced. In Volume 6 a new 'direct control' version of Powerscaling is featured which was introduced in Vol 4 but flushed out with comprehensive circuits and applied to 'sag' and sustain control as well in Vol 6. The new scaling circuits have many advantages for a DIY builder like greater noise immunity and less sensitivity to layout, etc.
I applied the new DC Power Scaling to a Trainwreck clone project and was really impressed with the improvement in 'playability' at lower volumes... the unmodified Trainwreck Express circuit is just too loud for domestic use, needing to be cranked to get the sweet tones it is renowned for.
One of the chapters in Volume 6 is dedicated to the Dumble amplifiers... something I was really looking forward to since many of my hobby projects focus on those circuits. I found this short chapter to be a good introduction to the overall architecture of the Dumble amps, written from the point of view of the evolution from the early modified standard amps that Alexander Dumble started out doing, but I felt the chapter fell short in discussing some of the more important subtleties of the later Dumble models.
Volume 6 also has lots of other material in it, including a great tutorial on designing really high output power amplifiers and a great chapter on high gain amplifier designs with real-world circuits referenced and detailed.
In Summary...
Kevin's books have a very empirical approach. He encourages you to set aside convention in some instances or not be afraid to try combinations of tubes or even pulling tubes and in all cases clearly explains why it is o.k. and points out any reasons why it wouldn't be o.k. All the examples in the books are very practical and he certainly has the DIYer in mind as he is writing.
Kevin's body of work is truly encyclopedic in nature, and considering that, one feature sorely lacking from his books is any kind of indexing... this is aggravated by the fact that Kevin constantly refers to previous writings rather than repeat himself in a new volume, and it is very difficult to put your finger on the reference even with the other book in hand. Perhaps search engine technology, like Google's ability to search protected content, could be put to good use in this case and provide a kind of 'auto-index' on the web of all of Kevin's books without actually giving away the book itself. Or better yet, how about an e-book format of Kevin's entire collection of TUT books... I think all of the e-book readers include searching capabilities... and Kevin's hand-drawn schematics would probably scale adequately and be very readable on the e-paper displays these devices feature.
Meanwhile, how do you get Kevin's books today? The best way to get the books is to directly order them from London Power Press. They now have a shopping cart on http://www.londonpower.com.
Article Source: http://EzineArticles.com/?expert=Mark_Douglas_Roberts
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