Power system generates a stable dc voltage 250v and ac heater voltage for tube lamps 6. Pspice spice simulations are a valuable tool that aid in the design of tube amplifiers. This is followed by explanations of components, the detailed. Audiophiles, guitarists and general hobbyists alike will find this book an invaluable source of detailed information on transformers, rectifiers, smoothing, highvoltage series and shunt. A thermionic valve or vacuum tube contains two or more electrodes suspended inside a glass bulb. Feedback, norman crowhurst, 1957, 63 pages thanks to keith carlsen. Tone controls are typically next in the circuit, and probably yield the most options for tweaking. Never touch the amplifier chassis with one hand while probing with the other hand because a lethal shock can run between your arms. Keep those filaments lit, design your own vacuum tube.
Designing tube preamps for guitar and bass is the most comprehensive guide to the design of tube based preamplifiers for musical instrument use, in a single volume. Includes designs using offtheshelf transformers and current production tubes. Four amplifiers for different purposes was designed and measured. In some classic guitar amplifiers, one can find as many as five dual triode vacuum tubes in use. This guide discusses all relevant aspects for an integrated pushpull vacuum tube amplifier design, including the power supply unit. Output amplifier consists of a 6p1p output tube and output transformer fig. Ive read about vacuum tubes, both as a guitarist using vacuum tube amplifiers for many years and as a teen constructing and using amateur radio gear. A designers guide to instrumentation amplifiers by charles kitchin and lew counts 3rd edition. The most common triode type found in guitar amps is the ecc83 12ax7, while the ecc81.
Instrumentation amplifiers inamps are sometimes misunderstood. The course starts with a discussion of the basics of electronic concepts. Explores all manufacturers and demystifys the inner workings of tube amps. Vacuum amplifier do not provide any protection against continuous shortcircuit conditions at the output 5. Amplifiers introduction amplifiers are used extensively in electronic circuits to make an electronic signal bigger without affecting it in any other way. Written for musicians, amp builders, and tube audio enthusiasts, design and construction of tube guitar amplifiers provides a complete yet easytounderstand explanation of how to design, modify, construct, and test tube amps. Also when calculating the gain of an amplifier, the subscripts v, i and p are used to denote the type of signal gain being used the power gain ap or power level of the amplifier can also be expressed in decibels, db. So summarizing, we are starting with the following conditions. If you have not been trained to work with high voltage then have an amp technician service your amp.
The key to learning to read amp schematics is to start small with the. The early fender amplifiers used a simple, crude treble cut control still labeled tone, like so. For amplifier 2, an ultralinear tap is needed, indi cated by sg1 tag 4 violet at 12 oclock and sg2. This the first video of many on design and build of an audio tube amp. This prototype was built for testing a new concept in linear amplifiers, which could be named abf class. Despite their best replication efforts, the consensus among performing and studio musicians remains that there is no substitute for a welldesigned tube amp. Basic theory of valves a thermionic valve or vacuum tube contains two or more electrodes suspended inside a glass bulb. Preamplifier consists of a 6n1p tube and is connected to the audio input. Generally we think of amplifiers as audio amplifiers in the radios, cd players and stereos we use around the home.
Merlin blencowe, designing highfidelity tube preamps morgan jones, valve amplifiers, 4th edition. Sep 01, 2009 written for musicians, amp builders, and tube audio enthusiasts, design and construction of tube guitar amplifiers provides a complete yet easytounderstand explanation of how to design, modify, construct, and test tube amps. The circuit structures seen in bjt and fetbased amplifiers commoncollector and commonemitter, common source and common drain, are paralleled in tube based circuitry commonplate and commoncathode. Class a power amplifier is a type of power amplifier where the output transistor is on full time and the output current flows for the entire cycle of the input wave form. After reading these books, i felt that i was ready to start designing the amp. Even now tube amplifiers still sound great perhaps better than ever before.
Book for musicians, amp builders, and tube audio enthusiasts. Tube amp design wikibooks, open books for an open world. Class ab amplifiers are the most common in larger guitar amplifiers because of their efficiency. The first part of the book has a rather indepth treatment of vacuum tube operation, and details of amplifier circuit design. In part that is because we now have access to modern components such as toroidal output transformers, extremely highquality resistors and capacitors, and many sorts of wire with good acoustic properties. However, some of these designs are now rendered obsolescent by changes in the availability.
Building a brand new valve amplifier using the rh84 design and offtheshelf components. Abstract amplifiers, which are devices that increase the gain of an audio signal, dominate modern audio technologies. Note that for the power gain you can also divide the power obtained at the output with the power obtained at the input. The tube cad journals first companion program, tcj filter design lets you design a filter or crossover passive, opamp or tube without having to check out thick textbooks from the library and without having to breakout the scientific calculator. In part that is because we now have access to modern components such as toroidal output transformers, extremely highquality resistors and capacitors, and many sorts of wire with. The pdf document will be laid out to print landscape on 11 by 17 inch. The following are disadvantages of vacuum tubes over solid state audio amplifiers as mentioned in 2 1. Following is a list of must have books for the serious tube amplifier designer. From the input to the phase inverter this book discusses in detail the inner workings and practical design of every part of a conventional guitar preamp, including the use of. Seventeen amplifier designs ranging from 3 to 1,100 watts are presented, along with tube data and design considerations. The class of an amplifier is selected to meet the overall requirements. From the diagram above, it should be clear this is also the voltage across the resistor r2. The phasesplitter is a very critical part of the pp amplifier, and its behaviour is of great importance for the performance of the amplifier. Multiband hf amps, have a few difficulties that grow more complex as more bands are added to it.
The amplifier being designed in this paper has two types of electron tubes, 4. Class d audio amplifier design pdf 54p this note covers the following topics. The sooner you learn to read amplifier schematics the sooner youll be able to analyze classic amp circuits and learn how the masters of amp design voiced their amps. Simple class a amplifier a 10w design giving subjectively better results than class b transistor amplifiers by j. A designers guide to instrumentation amplifiers, 3rd edition. It is not actually a new operating class, but has characteristics of the well known class ab and class f applied to the same amplifier. The design of this stage takes skill and care as explained in my earlier paper. Class a power amplifier tutorial with design and theory class a power amplifier. A class b rf linear amplifier will generate still more intermodulation distortion, but is acceptable in certain applications. A tube amplifier chassis contains lethal high voltage even when unpluggedsometimes over 700 volts ac and 500 volts dc. Being a guitarist who shares that opinion, i chose to design a tube amp of my own.
Singleended classa tube amplifier design and construction. Beside that, el34, el84, and 12ax7 vacuum tubes are used in many practical examples, to design the various parts of the circuits and to compute the values of the needed components. Vacuum tube amplifiers cost from 3 to 10 time as much as solidstate designs. The slides are pretty heavy on engineering design terms, but give a good feel for what it takes to construct and tune an audio amplifier using vacuum tube technology. Tube amplifiers have two subtypes ab1 grid current never flows ab2 grid current flows for part of the. Building valve amplifiers tube electronics for you and me. Introduction to the amplifier an amplifier tutorial. Stability becomes increasingly difficult when the frequency is raised into the 10meter range. Merlin has found his voice, which pleases far more than the odd, stilted voice in designing power supplies for tube amplifiers. If you want to build a tube amplifier and you dont want to just copy someone elses circuit it might be a good idea to learn how to design it. Starting with 160 meters, the difficulty of design and construction goes up, with the frequency. As a rank beginner, i bought this book to help me understand amplifier design so i could better diagnose issues with my tube amplifiers. Its much easier to analyze an amp circuit by studying its schematic than looking at its layout diagram.
Odern audio amplifiers are efficient, noisefree, and can be as powerful as needed for any given application. Vacuum tubes are heavier and bulkier than solid state designs 3. Setting out to design and eventually construct a tube. The amplifier is similar in design to the 15watt amplifier shown in fig.
Tube operation is explained, as are circuit principles. A very unassuming title for a 617page engineering book. Coming into the project, i knew that i wanted an amp with. The drive circuitry of the control grids is not shown i assume perfect. Inamps are used in many applications, from motor control to data acquisition to automotive. Vacuum tubes are more fragile compared to solid state 4. Class d amplifiers are the most commonly used in larger pa system amplifiers because of their efficiency. I have built my own sub enclosures, speakers, riaa preamp, pass f5 ss amplifier, rld tube amplifier, some class d amplifiers, jlh amplifier and more car audio systems then i can remember. If you are down with bode plots and circuit diagrams, though, it could serve as a nice introduction to building a class ab amplifier circuit. Well, radio building master greg charvat has you covered with his latest presentation, design your own vacuum tube audio amplifier.
Note that a 6l6 model was used in place of a 6v6 because it was readily available. Designing tube preamps for guitar and bass merlin blencowe. Designing power supplies for valve amplifiers is a unique guide to the operation and practical design of linear power supplies, especially for valve equipment. Designing power supplies for tube amplifiers antique. The anodes are connected to the primary winding, the cathodes to ground circuits 1, 2, and 3, and the middle of the primary to the highvoltage supply. Dec 30, 2019 designingpowersuppliesfortubeamplifiersmerlinblencowepdf 1a8c34a149 book title. Tube amplifier saulo quaggio, py2ko can a tube fulllegallimit amplifier be small and light. Building and modifying amplifiers is dangerous like most fun things. However, there are problems with nutube 6p1 which makes it useless in audio systems with high fidelity.
Class d audio amplifier design, trend in class d amplifiers, traditional linear amplifier, basic pwm operation, analogy to buck dcdc converter, power dissipation in gate driver, gate driver for class d applications, mosfet technologies and thermal design. Designing highfidelity tube preamps turned out to be one such spark. The first chapter, what is a vacuum tube, was quite understandable and included a bit more info than i found on the internet. Designing tube preamps for guitar and bass pdf download download. My design involves a fourstage preamplifier, which uses two dualtriode. Modern vfd vacuum tube demonstrated itself as a tube which can provide tube sound with low supply voltages. However, most highend amplifiers which are used in the gigs or recording studios uses tubes. Fundamentals of engineering electronics, william dow, 1937, 617 pages courtesy of an anonymous donor. Keywords audio, low frequency, thd, noise, vacuum tube.
Electron tube spice models are examined and used in the process. Hifi tube amplifiers often have no tone controls, and carefully design the stages to have a flat frequency response. Classa or b, cathode, fixed bias, and pushpull and singleended designs are covered, as are many frontend circuits. If youre interested in understanding, designing, or building greatsounding amplifiers and speaker systems, design and construction of tube guitar amplifiers and design and construction of guitar and bass speaker systems contain the information you need. How to design valve guitar amplifiers the valve wizard. Using 6 as a guideline, the following models were used in spice simulation. Tons of empirical data that demystify the 519 pages tube pdf file guitar amplifier power amps. Otona no kagaku science for adults product version vacuum tube ampli. As for the screen grids, in amplifier 1 the screen grid sg1 of the upper tube is connected directly to the high voltage power supply v1, as is the other lower screen grid, sg2.
Apr 10, 2010 the slides are pretty heavy on engineering design terms, but give a good feel for what it takes to construct and tune an audio amplifier using vacuum tube technology. During the past few years a number of excellent designs have been published for domestic audio amplifiers. A bibliography of must have tube electronics books. Most tube guitar amplifiers rely on vacuum tube triodes for preamplification, and driving certain sections such as a spring reverb, tone controls, or tremolo. Nfb eliminate these fluctuations so the engineers could spend their time. Electron tube technology, despite being outdated, inefficient, and inherently noisy, still manages to provide a tonal quality that some ears find more pleasing, despite its pitfalls. We do have a small radio, but it seldom gets turned on. The first tube amplifiers were constructed with triodes, directly coupled to high impedance loudspeakers, with interstage transformers, but without output.
Understandably, the properties and response of the vacuum tube triode have a great effect. The power amplifier involves three stages, two of which use a 12ax7, and. Some of them are long out of print, and can only be obtained from used book sellers, although they are occasionally seen for sale on the internet. Figure 1 shows several pushpull tube amplifiers only the power tubes and the output transformers primary winding. A class a output stage requires less filtering than a class ab output stage. The physical function of the tube the most common tube type in audio amplifiers regardless if it is in power stages or in pre amplifiers is the socalled triode svwp. Although aimed specifically at designing guitar amplifiers, principles of hifi have been included here so that audiophiles may find something of use too, and guitarists should be able to learn some of the science behind the mojo. Elements affecting this sound include the cleverly designed tone stacks, the specially developed loudspeaker, and the softedged distortion. All these tube amplifiers cost much more than modern solid state amplifiers. Next, vacuum tube amplifiers and wave forms discuss the principles of circuit design, respectively, for circuits that are essentially. Any air inside the bulb is thoroughly removed during manufacture, leaving only a vacuum. Free amplifier circuits books download ebooks online.
Designing audio power amplifiers bob cordell new york chicago san francisco lisbon london madrid mexico city milan new delhi san juan seoul singapore sydney toronto. A number of recent visitors have registered surprise that we do not have any music playing in our workshop. Since 1999 welcome to almost 500 posts and to over 50 articles on amplifiers, tube based preamps, crossovers, headphone amplifiers, singleended amplifiers, pushpull amplifiers, circlotron circuit design, hybrid amplifiers, cascode circuits, white cathode followers, groundedcathode amplifiers, tube series regulators and shunt regulators, the aikido amplifier. It is all tube design or combined, tube preamplifier with solid state power amplifier. This book offers a simplified method for designing tube power amps for audio. But, a monoband amp is still the easiest to design and use. Thus, i was able to use my preexisting knowledge of amplifier design, coupled with. Designingpowersuppliesfortubeamplifiersmerlinblencowepdf. Class ab amplifiers are more efficient than class a, but not as efficient as class b. Designing valve preamps for guitar and bass 2 fig 1. It is obvious, that the level at the end of the line is totally unpredictable and that endless adjustments have to be made. An improved vfo driver amp for tube rigs by james d.
The origin of the power amplifier design came from the schematic below, which. So we are going to need to set some simplifying assumptions. It thus has three electrodes where two of them called anode and cathode reflects the diode function of the tube according to svwp. Circuit design is dictated primarily by the operating frequency, output power, type of modulation, duty cycle, and available power supply. The quad power amplifier is made up of four tube amplifiers built into one chassis providing 80w rms each for the front. He is an equalopportunity designer to this day, having built amplifiers with vacuum tubes, bipolar transistors, and. Tube circuits can be di vided generally by their operating class and type of modulation employed. They also common in cell phones and laptop computers because they are more efficient and preserve battery life. There is a computer program that comes with this page to help you.
The vacuum tube guitar amplifier still sets the performance standard for the desirable sound of this music production instrument. Amplifier classes including class a, class b, class ab, class c and the like are widely seen when dealing with amplifier specifications and their design. Richard kuehnel, circuit analysis of a legendary tube amplifier. A stereo amplifier requires more filtering than a monoblock design. Designing tube preamps for guitar and bass pdf download. Calculate the component values and record your results in part 1 of the amplifier design record sheets. The guitar amplifier design course was developed for the designers, builders and suppliers of vacuum tube guitar amplifiers. Amplifiers are given a classification according to the way in which they are biassed and they operate. Moreover, in his latest effort, he quickly gets to the point. Here in north america the main power is 120v at 60 hz so vm 120v and fm 60hz. This is an excellent book, packed with concise, factual information on tube valve preamp designs, complete with all mathematical formulas for design.