The amp s tone is what really matters so dont just set a standard bias target like 70% for class ab amps and forget it. 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. The sound produced by a singleended amp is rather unique. Most push pull designs produce more power than single ended amps do, and this can be a big factor for inefficient speakers. Push pull tube power stage the solution to the above problem may well be the socalled push pull pp design.
One thing about diy audio is that it is a journey, not a destination, it never ends. Beside that, el34, el84, and 12ax7 vacuum tubes are used in many practical examples, to design the various parts of the circuits and to. Tube amplifiers, schematics, parts, triode amplifiers. If you have 82 dbwm multi driver monsters, youll have a hard time finding a single ended amp that will drive them to acceptable roomfilling and realistic sounding levels.
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 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. Homemade el346ca7 push pull tube amplifier with diy ultra. 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 calculator is for designing a complimentarysymmetry push pull diodecompensated classb amplifier. Two twintriode tubes are used, such as 6sn7 or 12au7 tubes. It discuss the design of the power stage, the phasesplit, and the input stage. The basic design has been around for a long time 50 years or so.
A valve amplifier or tube amplifier is a type of electronic amplifier that uses vacuum tubes to increase the amplitude or power of a signal. I will build a bigger kt88 push pull someday, now its time for el84 sweetness. Figure 1 shows several pushpull tube amplifiers only the power tubes and the output transformers primary winding. Push pull amplifier circuit, operation, advantages and. The main difference between the two types is in the connection of the tubes to the output transformer, and the type. The pcb is designed for a 1206sized inductor but if your kit has arrived with a slightly bigger inductor, then it is needed to mount it differently as shown in photo 1. Each tube will have an anode current of 8ma, so the constant current sink in the tail is adjusted to 16ma. There are many pentode good for audio amplifiers but the most common in the current production are the el34, 6550 and the kt88 so follows a compare table with the main characteristics and price. Optional rload in ohms typically the output transformer primary impedance only considered when pp push pull is selected number of tubes power tubes pre amp tubes.
Push pull outputs are present in ttl and cmos digital logic circuits and in some types of amplifiers, and are usually realized as a complementary. Push pull 6550 monoblocks diy project sarris custom tube amps. By trying out several different sets of operating conditions in the computer i could eliminate hundreds of possibilities without playing with electricity. Tcj push pull calculator helps tube audio amplifier designers develop push pull output stages that yield low distortion and long tube life. Tube bias calculator rob robinettes car and tube amp website. Tube bias calculator rob robinettes car and tube amp. Usually single power tube amps are class a and amps with two or more power tubes are class ab. This amp is called a 6v6 push pull amp, the 6v6 being the tube model, but whats this push pull business. With this solution you may double the output power with very few extra components except another tube, that is. The drive circuitry of the control grids is not shown i assume perfect.
In the case of a push pull stage, this current may flow from. A push pull amplifier is a type of electronic circuit that uses a pair of active devices that alternately supply current to, or absorb current from, a connected load. Output transformer primary impedance for push pull. The fender 5f1 champ is a class a cathode biased amp. 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. 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. Introduction the my first pushpull amplifier was terrible, as many commercial products, if comparated to the my single ended amplifiers 2a3 pse, 300b pse. Classes of amplifier operation rf amplifiers are classified a, ab, b or c according to the phaseangle number of degrees of current flow during each 360degree rf cycle over which plate or collectorcurrent flows. I have 95 db sensitivity speakers, so the lowish 5 watts of power produced by a triodestrapped pp el84 amp would be enough. This guide discusses all relevant aspects for an integrated push pull vacuum tube amplifier design, including the power supply unit. Triode300b 1st stage 6485, 2nd stage 12a4, 5u4g rectifier and 300b x2. Step by step design of a pushpull vacuum tube amplifier. They are most linear with ia 6ma, according to what i read, and my own testing.
Going fullthrottle, it never really crapped out like most pushpull tube amp. This kind of amplifier can enhance both the load capacity and switching speed. The key here is to still have the nondriven side idling through the ot, so that its d. Diy 12sl7 srpp pushpull kt88 tube amp diyaudioprojects. In terms of distortion and performance, push pull amplifiers are more efficient than singleended amplifier because of its push pull arrangement.
Pp2010 hiend push pull amplifier audio design guide. In this arrangement, one transistor amplifies the positive half cycle whereas another. Explaining or trying to how to use the opt software to design hifi transformers. After listening to my latest aikido pushpull headphone amplifier, i noted that the. 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. The main difference between singleend and push pull, is distortion. If youve been itching to try your hand at building such a thing, this looks like it could be a good place to start. New allnic amp design the m2500 push pull triode or pentode with a unique 5u4g direct heated tube rectifier. When various people decided to start making a tube amp for guitar they did the same thing everyone else did, looked at the catalog of a transformer maker in their country which was a way bigger business than the guitar amp company at this point and bought the transformer that company offered for 2x6v6 amps or 2x6l6 amps etc. The diodes d1 and d2 are identical and suitable types would be from the 1n4001 to 1n4007 series. The classic push pull class a design generates balanced harmonics and tube compression, giving you the sound than made tube amps the goto choice to begin with. The 300 beast is a 300b push pull amp that i designed and built several years ago. 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 default example values shown are for a typical audio amplifier with load resistance of 8.
The main problem of pushpull amplifier is the not perfect distortion decay with the. The other two can be used for either push pull or single ended. This unit has a very large frequency response range thanks to its srpp pre amp circuit. 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. Px25 1st stage 5654, 2nd stage 654, 5au4 rectifier and px25 x2.
The two main types of output stages for guitar amp use are singleended and push pull. Tcj pushpull calculator download glassware audio design. Design of push pull amplifier using vacuum tube gadgetronicx. There is a clarity that you dont get from the push pull design. I used a push pull parallel set of 5b854m tubes, which are basically 807 tubes in a slim bottle with a loctal base. The result is the fatboy 300b amp named as such because, like me, it is a tad overweight. Low to medium power valve amplifiers for frequencies below the microwaves were largely replaced by solid state amplifiers in the 1960s and 1970s. Step by step design of a pushpull tube amplifier use all needed notions to design an entire integrated push pull vacuum tube amplifiers. This arrangement mainly reduces the harmonic distortion introduced by the nonlinearity of the transfer characteristics of a single transistor amplifier. Oddblocks classa pushpull kt88 tube amplifier 12sl7. However, guitar amps rarely use matched valves and usually have a lessthanperfect phase inverter. As the output voltage rises, especially at high power, a tranny without sufficient inductance at bass frequencies can easily saturate creating intense distortion. The first setting is perfect for group a tubes and the second for group b.
Step by step design of a push pull tube amplifier use all needed notions to design an entire integrated push pull vacuum tube amplifiers. Since 1999 welcome to almost 500 posts and to over 50 articles on amplifiers, tubebased 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, tranformer coupling. Here has been implemented a design where the first and driver stage is a single ended configuration and only the power stage is a pushpull. Two examples of semelab push pull mosfets are shown in figure 1. Basic theory using 21stcentury technology to design vacuum tube preamps, power amps, and power supplies system design a professional methodology for crafting a complete guitar amplifier circuit simulation modeling vacuum tube guitar amplifiers using spice select a. It discusses the design of the global negative feedback loop. He has a lifelong experience from different sound recording and reproduction equipment. This design procedure and program works with either single ended or pushpull output stages.
Below is a complete frontend for a push pull output stage. I also very much appreciate the design and build quality of this amp, its a beauty to look at as much as the sound it can amplify. Some designer create a similar stage using as common resistor with low. All is not perfect however, the bass is not as in your face as the 300b push pull amp. The yaqin mc84l is a class a integration push pull tube amplifier that uses a highperformance ultralinear push pull circuit to bring rich acoustics out of your audio. If the modification was made to a pair of pushpull tubes virtually all output stages then it was almost. Spreadsheets are simple to program, provide some sophisticated mathematical functions and. Class b are pushpull amplifiers, similar to conventional solid state amplifiers, where there is a pushing tube and a pulling tube being driven. Classa pushpull tube power amplifier electronics diy. 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. The output stage is a selfinverting push pull sipp design after the compact hifi power amplifier by melvin leibowitz. Since 1999 welcome to almost 500 posts and to over 50 articles on amplifiers, tube based preamps, crossovers, headphone amplifiers, singleended amplifiers, push pull amplifiers, circlotron circuit design, hybrid amplifiers, cascode circuits, white cathode followers, groundedcathode amplifiers, tube series regulators and shunt regulators, the aikido amplifier, tranformer coupling. The survey is meant to give the reader a fair idea of how each part of how a standars electron tube amplifier works.
The most popular highend tube amps in the market top. By way of comparison my old solid state amp had 110w per channel and it in no way comes close to punch and depth of sound. This calculator is for designing a complimentarysymmetry pushpull diodecompensated classb amplifier. Initially had to answer the question classic push pull or a single ended amp. 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. Tube type and platetocathode voltage must be entered for all calculations on this webpage. Every tube in this system is a triode including the mcintosh c20 preamp that is used to drive this project. Because of the platetoscreen capacitance of a tetrode or pentode, the rf plate voltage developed in the output circuit causes an rf current to flow out of the screen lead to the chassis. Lundahl transformers old fashioned 30w push pull amplifier. To create a push pull amplifier is possible to use triode and pentode but obviously to test many configurations like the ultra linear we need a pentode. Tube amp design wikibooks, open books for an open world. Valve amps naturally have a high output impedance and the output voltage will automatically rise in an attempt to maintain constant power to the speaker. Gio writes in to tell us about his latest vacuum tube based audio amplifier design, the 5751 srpp el84 6bq5 push pull tube amp. Glow in the dark audio thoughts and opinions of a tube.
Even if the phase inverter is perfectly balanced it will inevitably go out of balance when the power. The amplifier stage is based on the compact hifi power amplifier. Bugera g5 infinium 5watt classa tube head sweetwater. Universal loadline calculator vacuum tube amplifiers. New allnic amp design m2500 push pull triode or pentode. Keep those filaments lit, design your own vacuum tube audio. The main feature is a double pole double throw dpdt switch or relay.
The one that is for the push pull amplifier only is the peak gridtogrid voltage. Design of an integrated pushpull tube amplifier made easy giuseppe amato on. There is a computer program that comes with this page to help you. Tcj pushpull calculator is a 32bit program that runs under windows. So starting the design somewhere in 1994 i decided to design. It is based loosely on a design that appeared in vacuum tube valley issue number 12 a few. Your amp s best bias setting is pretty subjective so play it while you adjust it.
When the switch is thrown to the right, connecting d to f and a to c the circuit operates as a conventional push pull power amp with cathode bias. The an300b goes as far as it can go, which is around 22 watts, and then it negotiates with you. These terms refer to the amplifier output stage circuit topology, which is the way in which the components in the output stage are connected. The main difference between singleend and pushpull, is distortion.
To help along with tube amplifier design and construction, i have put together a number of informative articles. This yaquin is rated at 45w per channel which in tube amplification is more than necessary. The power stage is a class b push pull amplifier and as already stated, when one tube increases conduction the other decreases it by the same amount. Design of an integrated pushpull tube amplifier made easy.
Chokeloaded triode direct coupled to dht driver, transformer coupled to the push pull 300b output tubes. Amps with power tube cathode resistors greater than 10 ohms are usually cathode biased. I keep running into tubes that dont list this so i need to be able to determine it. Valve amplifiers can be used for applications such as guitar amplifiers, satellite transponders such as. How do you find a set of operating conditions that will work with 3 different tube families. This knowledge is then used to design an electron tube amplifier in the software tool ltspice.
Download a pdf schematic of the amp wiring, the driver pcb schematic showing components for this build, and the power supply pcb schematic. Push pull the basic principle behind this amp is pretty cool and worth taking a look at. When pushed hard the amp did distort, but the nature of the distortion was benign. Since for power amplification it is usual to use pentodes or beamtetrodes, which produce predominantly odd harmonics, we can expect all. Plus, the bugera g5 infinium morph eq gives you the best of american and britishstyle eqs or anything in between, further expanding your sonic capabilities. Construction of push pull class a power amplifier the construction of the class a power amplifier circuit in push pull configuration is shown as in the figure below. Figure 1 shows several push pull tube amplifiers only the power tubes and the output transformers primary winding. This amplifier was featured on the january 2003 issue of the highfidelity audio. Such a topology has very big advantage over single ended designs. The low distortion, low internal resistance of this technology enables for a very nice. A push pull amplifier is a type of amplifier that can drive current in either direction through the load.
Tcj pushpull calculator helps tube audio amplifier designers develop pushpull. Class b amplifier and the classb transistor amplifier. Beside this is a bad idea for a power amp, this is really what a lot of people call a real tube sound. 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. I used tango nc14 interstage and fx405 output transformers, which ive had around for a while.
Pushpull circuits and wideband transformers rf design. In this chapter, we use all notions introduced previously to design, from scratch, a stereo pushpull tube amplifier. J310 lownoise, pushpull broadband hf pre amplifier ver. This 6v6 amp was built following the push pull pp el84 6v6 dynaco a410 output transformer schematic. Nov 22, 2015 this the first video of many on design and build of an audio tube amp. A perfectly balanced push pull stage will cancel all even harmonic distortion and sum odd harmonic distortion generated within the power stage. If you design build a push pull amp, you can have a lowpower quasisingleended option by turning off the drive to one side of the push pull output. A 12dw7 could be used on the bottom, if the 12ax7 section were used for the input stage and the 12au7 section were used for the activeload triode. Tcj push pull calculator is a 32bit program that runs under windows 9xntme2000xp. Diy push pull pp 6v6 6v6gt tube amplifier with hammond transformers diy push pull pp 6v6 6v6gt tube amplifier schematic. It also discusses how to design power supply for the fixed bias circuit and for the filaments of the vacuum tubes.1379 50 1382 1479 132 654 860 1435 1355 168 63 182 480 891 1352 1361 1300 252 683 497 1434 703 991 998 1274 813 1314 277 515 334 294 1190 1188 47 19 496 1488 37 498 1202 375 793 1398 31 338 987 750 1369 1186 1181 921