This classa push pull tube power amplifier uses a pair of push pull class a, ultra linear mono block tube amplifiers that can be used with several different vacuum tubes including kt77 6l6gc kt88 with a 12sl7 driver and 6no30 tubes. Push pull the basic principle behind this amp is pretty cool and worth taking a look at. 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. With landmark design work such as the author presents here, the future of the tube amps, which reached their peak around the middle of this century, appears quite strong as we head into a new millennium. In this chapter, we use all notions introduced previously to design, from scratch, a stereo pushpull tube amplifier. Very few designs differing from these two have proven fit for real life, the. It contains simple, clear descriptions of the theory of valve amplification and the design of circuits, together with practical stepbystep instructions for building a number of excellent amplifiers. But he does mean if you spend a crap load on a tube amp then its better to just go with a set amp, have slightly more power, more compatibility, and.
The amplified audio from the 2 output valves, push pull is in opposite phase 180deg. Pushpull the basic principle behind this amp is pretty cool and worth taking a look at. A pushpull tube design and singleended class a designs. Parallel pushpull 300b tube amplifiers diy audio projects. The most popular highend tube amps in the market top. To wire inphase one heater wire would be connected to pin 2 on one power tube and pin 2 on. The spreadsheets generated for use with this book are specific to the manual calculations. Roger gibboni founder of rogers high fidelity presents to the new jersey audio society about the differences between singleended tube amplifiers and pushpull tube amplifiers. Sep 29, 2010 parallel push pull 300b mono amplifiers rudolf moers from the netherlands has kindly sent us details of his parallel push pull 300b monoblock tube amplifiers to share with the diy audio community. Parallel pushpull 300b mono amplifiers rudolf moers from the netherlands has kindly sent us details of his parallel pushpull 300b monoblock tube amplifiers to share with the diy audio community.
Hello, between a push pull tube design and singleended class a designs amp, is singleened class a better in sound quality, why. This design procedure and program works with either single ended or pushpull output stages. The 6ck4 is an indirect heated triode originally intended for tv service as a vertical deflection amplifier. This amplifier design uses 6ck4s in the output stage. This classa pushpull tube power amplifier uses a pair of pushpull class a, ultra linear mono block tube amplifiers that can be used with several different vacuum tubes including kt77 6l6gc kt88 with a 12sl7 driver and 6no30 tubes. This guide discusses all relevant aspects for an integrated pushpull vacuum tube amplifier design, including the power supply unit. After many years designing single ended amplifiers i have decided to start a series of test about the push pull amplifiers. The yaqin mc84l is a class a integration pushpull tube amplifier that uses a highperformance ultralinear pushpull circuit to bring rich acoustics out of your audio. These range from a 3w singleended amp to a 20w push pull power amp, including the outstanding mullard 510 design. An easily constructed highquality singleended 8w amplifier using standard valves and the lundahl ll 1664 output transformer.
Pushpull circuits and wideband transformers rf design. Its a slightly more complex pushpull amp but its surprisingly similar to the little champ. Simple and elegant push pull amplifier circuit designdiagram and its working principle explained. Anyhow, i am now debating on my amp selection and would like a bit of advice from those who are familiarized with the pros and cons and audible characteristics of both 300b845211 etc based set amps, and generally higher wattage pushpull designs. 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. In this combination one act as push type and the other acts as pull type.
If youre familiar with tube amplifiers, you know that the. Push pull amplifier circuit diagram class a, class b and. The technique was wellknown at that time and the principle had been claimed in an 1895 patent predating electronic amplifiers. I used a pushpullparallel set of 5b854m tubes, which are basically 807 tubes in a slim bottle with a loctal base. Lecture 060 pushpull output stages 11104 page 06011 ece 6412 analog integrated circuits and systems ii p. Coates 2007 2012 power amplifiers introduction to power amplifiers power amplifiers amplifier circuits form the basis of most electronic systems, many of which need to produce high power to drive some output device. Depending on the tranny design there may be 2,000 turns of wire in the primary and 90 turns for the secondary winding. If the singlestage amplifiers are utilized lot of heat dissipation occurs in the circuit and so the efficiency is less though it gives 90% amplification of the input signal. Beside that, el34, el84, and 12ax7 vacuum tubes are used in many practical examples, to design the various parts of the circuits and to. Lundahl transformers old fashioned 30w push pull amplifier.
Pushpull circuits are widely used in many amplifier output stages. After the 50s, the growth of new ideas in tube amplifier circuitry declined, and standardized designs became generally accepted, such as the lafayette 2 x el84. This book, in print from 2008 until 2020, has been updated, expanded, reorganized, and replaced by guitar amplifier electronics. Weve done the work for you and found 5 of the most popular high end tube amps on the market. Singleended amplifiers tend to be bigger and more expensive than push pull, but they have a more natural transfer curve. Step by step design of a pushpull vacuum tube amplifier.
If the modification was made to a pair of pushpull tubes virtually all output stages then it was almost. Vacuum tube circuit design guitar amplifier power amps. Any suggestions or as i seem to be getting told should i stick with sets and try to find something more powerful like maybe something from art audio. Learn what is class a pushpull amplifier in electrical engineering. A very important consideration in attempting to create an amplifier with a natural characteristic is the selection of the gain devices. One transistor pushes the output on positive half cycle and other pulls on negative half cycle, this is why it is known as pushpull amplifier. In my book, i explain how to change an amp from pentode pushpull, into an ultra linear design and even into a triode pushpull design. Figure 1 shows several pushpull tube amplifiers only the power tubes and the output transformers primary winding. The tube exhibits very good linearity at moderately high idle currents of around 30ma and at this level is dissipating roughly 10 watts. The valve wizard pushpull how to design valve guitar. Download a pdf schematic of the amp wiring, the driver pcb schematic showing components for this build, and the power supply pcb schematic. The drive circuitry of the control grids is not shown i assume perfect.
I had in the past designed some pretty amazing ss circuits that could do warm tubelike od, but the clean aspect depth and dimension of my ss amps were noticeably lacking when abd with a good well tweaked tube amp. It consists of two transistors in which one is npn and another is pnp. Power tubes wired in push pull should also be wired inphase to take advantage of common mode noise rejection inherent in the push pull circuit. Two examples of semelab pushpull mosfets are shown in figure 1. Im thinking 6sn7 push pull, 12au7 push pull maybe it is possible since you have the models. It did take some time for claus to fulfill his promise, but on the other hand he not only gave us a schematic, but a complete building instruction of a 30w pushpull amplifier, including a comprehensive theory section which discusses different tube amplifier design issues. These are simply the combined anode characteristics of the stage, as if the two valves in the circuit are rolled into one big valve which as far as the output transformer is concerned, they are. Design and construction of a pair of push pull classa, ultralinear mono block tube amplifiers that can be used with several different power vacuum tubes including el34, kt77, 6l6gc, 6550, kt88, kt90.
A push pull valve amplifier almost invariably follows one of the two schemes shown in block. An integrated amplifier includes all components needed to produce an. The mini block tube amps use a 5751 twin triode to drive the el84 pushpull output stage which is biased into classa operation, ultralinear mode. I decided to first build a more conventional amplifier to use as a benchmark for a future selfsplit design, and this amp is the result. An easily constructed highquality singleended 8w amplifier. If youve been itching to try your hand at building such a thing, this looks like it could be a good place to start. Push pull vs otl vs set tube amps super best audio friends. Any valve textbook describing how to design a pushpull stage will explain how to draw composite characteristics. Basic theory a 21stcentury approach to understanding preamp, power amp, and power supply design. Even the most carefully considered designs need a little fettling once built. Circuit simulation a deep dive into spice tube amp modeling the. I have said it before and ill likely say it again, you must have a tube manual to work with tubes.
Diy audio projects doityourself hifi for audiophiles. Economy phonograph amplifier lowcost hifi amplifier. Easy to build pushpull amplifier using plitron output and. The most popular highend tube amps in the market top tube. Posted on 20160606 by noam bronstein in amplification. To improve the full power efficiency of the previous class a amplifier by reducing the wasted power in the form of heat, it is possible to design the power amplifier circuit with two transistors in its output stage producing what is commonly termed as a class b amplifier also known as a push pull amplifier configuration. If youre here then youre probably thinking about tinkering inside one. The tube amp proudly sits as a cornerstone of many a home setup. For me, the ultrafi was the last piece of the puzzle in my quest to design an ss amp that can rival tube amps. What is class a pushpull amplifier electronic devices. Two examples of semelab push pull mosfets are shown in figure 1.
Set vs pushpull tube amps advice steve hoffman music forums. Maybe something like a granite audio or a bruce moore design amp. The origin of the power amplifier design came from the schematic below, which came from the 1959 rca receiving tube manual tech series rc19. Diy el84 pushpull classa, ultralinear amplifier 30 september 2012 bruce heran of oddwatt audio outlines the design and construction of monoblock pushpull el84 6bq5 valve amplifiers. Design of push pull amplifier circuit using vacuum tubes. The guitar signal on the upper power tube grid changes the current flowing through the tube which causes a voltage drop across the cathode resistor. This is to certify that the thesis entitled design of high performance class b push pull amplifier, submitted by abhishek anand roll. Vacuum tube amplifiers cost from 3 to 10 time as much as solidstate designs. Oct 20, 2009 gio writes in to tell us about his latest vacuum tubebased audio amplifier design, the 5751 srpp el84 6bq5 pushpull tube amp. This chapter discusses how to design an integrated pushpull vacuum tube amplifier.
This classa pushpull tube power amplifier uses a pair of push pull class a, ultra linear mono block tube amplifiers that can be used with several different vacuum tubes including kt77 6l6gc kt88 with a 12sl7 driver and 6no30 tubes. Pushpull amplifiers are the combinations of two bipolar junction transistors that is one of pnp type and the other is of npn type. Sep 22, 2019 the last thing you want is to have that moment of regret when you install a new tube amp and find that you overpaid when a cheaper priced model would have had all the same features. This amp is called a 6v6 push pull amp, the 6v6 being the tube model, but whats this push pull business. This article first appeared in the japanese magazine radio technology, december 2011. Hi giuseppe, i dont know if its easy to do but having some double triodes on reactive loads would be a hell of and addon. Building valve amplifiers tube electronics for you and me. Singleended class a operation is less efficient than pushpull. It did take some time for claus to fulfill his promise, but on the other hand he not only gave us a schematic, but a complete building instruction of a 30w push pull amplifier, including a comprehensive theory section which discusses different tube amplifier design issues. Gadgetronicx electronics circuit diagrams and schematic designs amplifier circuits design of push pull amplifier using vacuum tube. Apr 30, 2010 560v dc supply is connected to the ct center tap of the primary winding.
We will design a hifi amplifier that provides roughly 12 watt rms, using. Class b amplifier and the classb transistor amplifier. I apologize for the long post before hand i have recently decided to switch things over to a tube driven setup, for a few reasons. In my book, i explain how to change an amp from pentode push pull, into an ultra linear design and even into a triode push pull design. The main problems that should be dealt with are low power output and efficiency. Any valve textbook describing how to design a push pull stage will explain how to draw composite characteristics. A push pull valve amplifier almost invariably follows one of the two schemes shown in block diagrams below. How to design valve guitar amplifiers the valve wizard. Hoffman amplifiers tube amp forum, kagliostro 12au7 push pull schematic welcome to the hoffman amplifiers forum. Figure 1 shows several push pull tube amplifiers only the power tubes and the output transformers primary winding. But the gain does not stop there because both the demands on the output transformer opt and the regulation of the supply gets less.
Power amplifiers amplifier circuits form the basis of most electronic systems, many of which need to. Ive been a tube guy for about 22 years and an set guy for 7. I shall not give you a step by step building manual, only some guidelines. The original idea when these valves were purchased was a selfsplit output stage, so a complete pushpull amplifier could be built using just two valves a twin triode preamp valve and the gu17. This amp design features the 6336a power triode tube, along with push pull class a operation, no overall feedback, low distortion, approximately 20w of output power, reliability, and highperformance sound. 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. Eight push pull amplifier circuits with combinations of negative and. Classa pushpull tube power amplifier electronics diy. Building your own guitar amp is a rewarding pastime, but learning how to do it can be time consuming and frustrating sometimes. It refers to a special case of differential circuits, where a whole signal is made up of the difference of two voltages, a negative and a positive technically speaking, only the output stage is push pull, but both are differential. This book is a beginners guide that brings you, from the basic concepts of vacuum tubes, up to the design of a complete integrated pushpull vacuum tube amplifier. It uses a single pentode stage for the preamp, a selfsplit push pull power amp which requires no phase inverter and a field coil speaker.
Gio writes in to tell us about his latest vacuum tubebased audio amplifier design, the 5751 srpp el84 6bq5 pushpull tube amp. This book first introduces the needed principles, to designing and understanding vacuum tube amplifiers. Mullard circuits for audio amplifiers primary windings. Design of push pull amplifier using vacuum tube gadgetronicx. Power tubes wired in pushpull should also be wired inphase to take advantage of common mode noise rejection inherent in the pushpull. For inphase wiring you would run one heater wire from pin 9 of one preamp tube to pin 9 of the next tube. Nov 10, 2019 diy el84 push pull classa, ultralinear amplifier 30 september 2012 bruce heran of oddwatt audio outlines the design and construction of monoblock push pull el84 6bq5 valve amplifiers.
Very few designs differing from these two have proven fit for real life, the quad ii being a notable exception you will find the diagram in the appendix together with a brief explanation. Universal loadline calculator for vacuum tubes vacuum tube. Department of electrical engineering national institute of technology, rourkela odisha, india769008 certificate this is to certify that the thesis entitled design of high. One thing about diy audio is that it is a journey, not a destination, it never ends. Circuit simulation a deep dive into spice tube amp modeling. Pushpull amplifier is a power amplifier which is used to supply high power to the load. Valve amplifiers, working in pushpull classa or ab1, and perforce. Singleended amplifiers tend to be bigger and more expensive than pushpull, but they have a more natural transfer curve. How to build a tube amplifier rob robinettes car and tube.
We start from the output stage, then the splitter and input stages. For this reason it is called a switching amplifier in a class d amp, the input is compared to a high frequency 100khz ramp waveform. This amp is called a 6v6 pushpull amp, the 6v6 being the tube model, but whats this pushpull business. The 829b is very similar to the gu29 and fu29 and to the likely original 3e29. It refers to a special case of differential circuits, where a whole signal is made up of the difference of two voltages, a negative and a positive technically speaking, only the output stage is push. The mini block tube amps use a 5751 twin triode to drive the el84 push pull output stage which is biased into classa operation, ultralinear mode. This design procedure and program works with either single ended or push pull output stages. Push pull class a power amplifier so far, we have seen two types of class a power amplifiers. The level of distortion is inherently low in a triode pushpull output. This book is a beginners guide that brings you, from the basic concepts of vacuum tubes, up to the design of a complete integrated push pull vacuum tube amplifier. To improve the full power efficiency of the previous class a amplifier by reducing the wasted power in the form of heat, it is possible to design the power amplifier circuit with two transistors in its output stage producing what is commonly termed as a class b amplifier also known as a pushpull amplifier configuration pushpull amplifiers use two complementary or matching transistors. Its a slightly more complex push pull amp but its surprisingly similar to the little champ. It is relatively easy to find introductory information on how to design simple amplifier stages.
It all results in an easy to build and to repair, and to modify amplifier. Diy 12sl7 srpp pushpull kt88 tube amp diyaudioprojects. Your simulator is so much quicker than opening orcad or another spice simulator. How to build a tube amplifier up tube amp design 5f6a mods bassman micro how the. A very important consideration in attempting to create an amplifier with a natural characteristic is. Singleended class a operation is less efficient than push pull. It should be quite obvious from the photographs that the design and construction of a pair of amplifiers this size is by no means a small undertaking. Design of an integrated pushpull tube amplifier made easy. Pickup 1 tube preamplifier for magnetic phonc pickup 2 tubes preamplifier for tapehead preamplifier for lowoutput micr mixer balancing unit for twochannel stereophonic system. Push pull transistors semelab plc produces a wide range of push pull mosfets and this application note is intended as a guide to some circuit design principles which are particularlyappropriate when using these devices. The amplifier stage is based on the compact hifi power amplifier.
A class d amplifier is defined as one in which the output device is conducting for the minimum amount possible. The voltage can actually vary very much in a well balanced push pull design and this is because push pull actually means that it only amplifies differential signals. This guide discusses all relevant aspects for an integrated push pull vacuum tube amplifier design, including the power supply unit. Tube amp design wikibooks, open books for an open world. Pushpull amplifiers working,advantages and applications. A pair of audion tubes connected in pushpull is described in edwin h. Colpitts us patent 17384 granted in 1915, although the patent does not specifically claim the pushpull connection.