6l6 tube amp design pdf

Certain assumptions may be made as long as the power output of an amp is known. Fender has been using them since the 1940s and since then there have been many others who have designed hugely popular tube amplifiers that rely on the 6l6 tube types for their tone. Many amateur radio operators used the 6l6 in class c service for transmitters over the years because it was inexpensive due to mass production, and it could be salvaged from scrapped tv or audio equipment. Design and construction based on the sylvania 6l6gcstr387 extrarugged construction for use in music amplifiersthick mica spacers and extra bracing reduce microphonic effects and resist mechanical and thermal shocks. The spreadsheets generated for use with this book are specific to the manual. If you have built any of these circuits, we would love to hear from you so send us your comments. Working with data and trying out a few configurations led me to believe that the 5k.

This project is intended to be built as designed and not piece milled with other designs. This tube is commonly found relabeled by fender and groove tubes to gt6l6b. After reading these books, i felt that i was ready to start designing the amp. Biasing bias switching circuit design effects loops kit questions. My most recent comparison would be my budda superdrive with el84s and a splawn supersport with 6v6s. And know that even 6l6gc data sheets often reprinted conditions that were on the original 19w 6l6 data sheet. Coming into the project, i knew that i wanted an amp with roughly 60 watts of output that had two preamp channels with separate tone controls. And know that even 6l6gc data sheets often reprinted conditions that were on the original 19w 6l6. This style of amp uses two out of phase signals to drive the pair of output devices. One was simulating the el34 amplifier shown below while another was simulating the 6l6 amplifier, and the third was crunching on the kt88 amp. Even though 6l6 tube is used primary in guitar vacuum tube amplifiers, many manufacturers use this tube in audiophile designs. A higher voltage 450v deep class ab amp might use a 4k primary possibly smaller, while a lower voltage 350v hotter class ab amp might use a 6.

Using 6 as a guideline, the following models were used in spice simulation. Petersburg, russia, and is designed to be a direct replacement for any 6l6 type. Built to rigid military standards, the sovtek 5881wxt will tolerate higher voltages than most other 6l6 tubes. Kt886550 compatible single ended amplifier 5th jan 2014 using fladance mp player 8w rms. Singleended classa tube amplifier design and construction. This kit employs commonly used pentode 6l6 6l6gc6l6gcr vacuum tubes for the output stage of a class a amplifier with 12ax7 as input stage. Some players prefer the extra clarity and punch of the 6l6.

Typical operation and characteristics class a, power amplifier, pentode connection. Here below are the main features of this power amplifier. It also results in a more efficient power output which is why a pair of tubes in these amps can produce 65 watts. Svetlana sv6l6gc high performance audio beam power. A 50 watt amp with two 6l6 or el34 tubes, or a 100 watt amp with four 6l6 or el34s, is. The tube amplifier replaces a solidstate amplifier which was driven by a tube. Other tad tubes 6l6 tube types additional information and downloads. The beam tetrode design of the 6l6 allowed rca to circumvent philips pentode patent. This is our collection of diy and hifi audio schematics. The july 63 763 fender amplifier design is considered by most as the high water mark of fender amplifier design. The phasesplitter is a very critical part of the pp amplifier, and its behaviour is of great importance for the performance of the amplifier. Svetlana sv6l6gc high performance audio beam power tetrode t. Preamplifier consists of a 6n1p tube and is connected to the audio input. A newly developed active automatic bias adjustment function automatically adjusts the bias for.

Pspice spice simulations are a valuable tool that aid in the design of tube amplifiers. There is a computer program that comes with this page to help you. Look at the back of any all tube amp, and youll see warmly glowing glass bottles in a variety of shapes and sizes. Basic theory a 21stcentury approach to understanding preamp, power amp, and power supply design. Download a pdf schematic of the amp wiring, the driver pcb schematic showing components for this build, and the power supply pcb schematic. The output stage uses one 6l6 tube configured as class a amplifier with singleend output. The tad 6l6wgcstr has an blackplate design, gold grid wire, double getter construction, nonoise filaments, and a 1. The sovtek 5881wxt tube is a reliable beam tetrode delivering a warm, round tone that sweetens any vintage or modern guitar tube amp design. Circuit of tube amplifier device the output transformer is an important part of the amplifier requiring a thorough parameter. Output amplifier consists of a 6p1p output tube and output transformer fig. Discover the differences in listening pleasure with the flexibility of various power tubes and output modes.

Ive owned lots of el34 amps, a couple of 6l6 amps, a 6v6 amp and a couple of el84 amps. Builtin rectifier and regulation circuitry with inductor option. The output transformer is too small and will be replaced with a 20w one with. As a result, most guitarists and some manufacturers simply refer to the 6l6gc as 6l6. Amp diy 6550 gear amps 6l6 6v6 august 2015 el34 el84 tube combo tube head ampeg fender marshall vox. Spec said will be get 10w rms with 6l6 but actually never get 10w rms. Because of this, there are many versions by different manufacturers. Pdf 6600ohm 6l6 tube 6l6 pushpull audio circuit rca 6l6 tube 6l6 6l6, tube class ab audio power amplifier rca tube 47 6l6 g. Check out our 6l6 tube catalog page for 6l6 tubes we stock. Close manufacturing specification tolerances and improved processing provide improved reliability and superior sonic performance. This design procedure and program works with either single. Lets start by looking at the simple standard tube amplification circuit that you will see again and again as you study tube amp.

Symmetrical layout design in signal paths for both channels. The preamp and long tail pair ltp phase inverter are 100% ab763 vibroverb but the power amp uses a single, cathode biased 12au7 power tube wired in true pushpull. Class a1 singl tube pushpull u a 250 v 270 v u g2 250 v 270 v u g1 14 v 17,5 v i a 72 ma 4 ma i g2 5 ma 11 ma r a 22,5 k. I remember that 6l6 also the 5881 and kt66 can diffuse and 25w 6l6gc can broadcast 30. Circuit simulation a deep dive into spice tube amp modeling. Audio power amplifier circuit diagrams circuit schematics.

A 50 watt amp with two 6l6 or el34 tubes, or a 100 watt amp with four 6l6 or el34s, is a pushpull amp. To get 60 watts output, i decided to use two 6l6 beam power pentodes in a class ab1 pushpull but cathode biased configuration. Similar circuits appeared as early as 1951 using a 6aq5 and a 6bh7 vacuum tube. I never thought twice about the type of tubes, i bought and kept them based on tone. Being a guitarist who shares that opinion, i chose to design a tube amp of my own. The inside of a combo tube amplifier is a superabusive environment for tubes because you crank up the volume, create a huge amount of sonic vibration, directly couple the tubes to the chassis of your amp and then.

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. Please see the substitutes at the top of the page for more details. Biasing an amp requires some knowledge of tube amp circuits and experience with high voltage. So those big 500w guitar rigs made by some companies lose their numerical impressiveness if you do a sidebyside listening test with a tube system. From schematic to ordering parts to cab design, it is all here and explained in detail. Rr763m blackvibe micro this is the one watt, 12au7 pushpull power tube version of the blackvibe that is perfect for true bedroom level practice and studio work. At the time when guitar amplifiers hit the market, the art and science of making tubes had hit a high point, with various kinds of tubes, which, when applied to audio, yielded clearly different results. As you use your tube amp, tubes wear out due to the heat it. I believe the bjt tube cascode design is essentially a class b power amp so idle current through the outputs is lower than you would normally bias a ab class amp. Antique radio forums view topic how about this 6l6 amplifier. Feel free to send us your hifi audio schematics and we will add them here. The octal 6ls7 or 12sl7 could be used instead of the 12ax7, but it has less gain. El34 tubes were quite popular in stereo amps years ago and you can hear them today by listening to those such as the marshall origin20c, the evh 5150iiis, and mesaboogie lone star special.

A clippable solidstate amp of 200250w sounds about as loud as a 50w tube amp for guitar. Single tube pushpull ua 250 270 v ug2 250 270 v ug1 14 17,5 v ia 72 4 ma ig2 5 11 ma ra 22,5. Pushpull 5881 6l6 amplifier this was the second amplifier i built for myself and was completed in september 2006. Note that any 6l6 variant should have the same characteristics, hence given the normal actual tube vs bogie tube variance, the power outputgainheadroom of an amp shouldnt alter according to the particular 6l6 variant used. Apr 19, 2012 diytube 6l6 clementine single ended tube amp shannon parks, owner of diytube, has made a number of projects available since 2003 when the diytube st35 clone was made available. The design of this stage takes skill and care as explained in my earlier paper. The tubebased adjustable regulator is based on one in the 1963 edition of the radio amateurs handbook that uses an 807 and a 6au6.

Lets start by looking at the simple standard tube amplification circuit that you will see again and again as you study tube amp schematics. Note that a 6l6 model was used in place of a 6v6 because it was readily available. Unlike the el34 power tube, 6l6 tubes generally sound a little cleaner and tend to have a bit more beef in the low end as well as more bite on the top. I tried each set of conditions on each simulation, and pushed the values around until i found a set that worked with all 3 tube types. There is only one tube family that has the right tone, the 6l6 family. Developed in 1907, the triad vacuum tube quickly became the mainstay of electronic equipment around the world.

Single ended 6l6 hifi pentode preamp amplifier, tube. The power amplifier involves three stages, two of which use a 12ax7. Support either open loop gain or close loop feedback. The origin of the power amplifier design came from the schematic below, which came from the 1959 rca receiving tube manual tech series rc19. I was asked by kegger on the ak tube amp audio forum if i was interested in designing a pcb based amp on the 6l6 output tube family. Paradoxically it is possible to use a better output transformer in a given tube amplifier design and get worse performance due to the wider bandwidth of the transformer allowing oscillation to occur where it did not before with a lesser transformer. The svetlana sv6l6gc is manufactured in the svetlana factory in st. That said, in my ears and in my amp egnater tourmaster 4100 head, the tung sol 6l6gc 7581 wonders. Despite their best replication efforts, the consensus among performing and studio musicians remains that there is no substitute for a welldesigned tube amp.

Design my design involves a fourstage preamplifier, which uses two dualtriode 12ax7 tubes. Assembly manual schematic parts list tubes and applications design simulations. As before, i wanted to control for constant plate voltages, choose several values based on data sheet information and vary the bias levels at these plate voltages to see how the tube performs. These books gave a background on vacuum tubes and also their applications to guitar amplifiers. We stock a large number of premium 6l6 tube types in matched pairs, quads and sextet configuration, ready to be plugged in. It uses a power transformer scavenged from a fisher 400 receiver and hammond 1645 output transformers, and produces 25 watts per channel. Maximum circuit values for maximum rated conditions. Nov 02, 20 pushpull 5881 6l6 amplifier this was the second amplifier i built for myself and was completed in september 2006. The hh scott 220 is similar but with a 6sn7, which has even less gain, and a 6j5 preamp tacked onto the front the volume pot also moves to there. This is a single power amplifier using natural sounding and powerful 6l6gc tubes. You can rightclick this graphic and select open image in new tab or save image as to make it easier to access while looking at the schematics below. Diytube is both shannons small business located in central illinois and a closeknit forum featuring a handful of helpful and prolific members. The tube amplifier replaces a solidstate amplifier which was driven by a tube preamplifier. If you are uncertain that you are experienced enough to work on a live high voltage amp, please take your amp to a professional to get it biased.