6l6 tube amp design pdf

To get 60 watts output, i decided to use two 6l6 beam power pentodes in a class ab1 pushpull but cathode biased configuration. Nov 02, 20 pushpull 5881 6l6 amplifier this was the second amplifier i built for myself and was completed in september 2006. That said, in my ears and in my amp egnater tourmaster 4100 head, the tung sol 6l6gc 7581 wonders. The output transformer is too small and will be replaced with a 20w one with. 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. Circuit of tube amplifier device the output transformer is an important part of the amplifier requiring a thorough parameter. Petersburg, russia, and is designed to be a direct replacement for any 6l6 type. 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. Some players prefer the extra clarity and punch of the 6l6. 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. My most recent comparison would be my budda superdrive with el84s and a splawn supersport with 6v6s. Svetlana sv6l6gc high performance audio beam power tetrode t.

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. As you use your tube amp, tubes wear out due to the heat it. A newly developed active automatic bias adjustment function automatically adjusts the bias for. 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. After reading these books, i felt that i was ready to start designing the amp. I never thought twice about the type of tubes, i bought and kept them based on tone. Audio power amplifier circuit diagrams circuit schematics. Antique radio forums view topic how about this 6l6 amplifier. Other tad tubes 6l6 tube types additional information and downloads.

Please see the substitutes at the top of the page for more details. The beam tetrode design of the 6l6 allowed rca to circumvent philips pentode patent. And know that even 6l6gc data sheets often reprinted conditions that were on the original 19w 6l6. 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.

It uses a power transformer scavenged from a fisher 400 receiver and hammond 1645 output transformers, and produces 25 watts per channel. Pdf 6600ohm 6l6 tube 6l6 pushpull audio circuit rca 6l6 tube 6l6 6l6, tube class ab audio power amplifier rca tube 47 6l6 g. The sovtek 5881wxt tube is a reliable beam tetrode delivering a warm, round tone that sweetens any vintage or modern guitar tube amp design. Ive owned lots of el34 amps, a couple of 6l6 amps, a 6v6 amp and a couple of el84 amps. Built to rigid military standards, the sovtek 5881wxt will tolerate higher voltages than most other 6l6 tubes. Svetlana sv6l6gc high performance audio beam power. Spec said will be get 10w rms with 6l6 but actually never get 10w rms.

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. 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. If you plan on buying a newoldstock nos 6l6gc, be careful not to order the original, metal tube 6l6 which will likely sound bad and wont be able to take the heat from your guitar amp. Pushpull 5881 6l6 amplifier this was the second amplifier i built for myself and was completed in september 2006. Because of this, there are many versions by different manufacturers. Biasing bias switching circuit design effects loops kit questions. The output stage uses one 6l6 tube configured as class a amplifier with singleend output. The octal 6ls7 or 12sl7 could be used instead of the 12ax7, but it has less gain.

Builtin rectifier and regulation circuitry with inductor option. I decided to build this small single ended amplifier based on 6l6 vacuum tube using a classic three stage single ended design. Despite their best replication efforts, the consensus among performing and studio musicians remains that there is no substitute for a welldesigned tube amp. A 50 watt amp with two 6l6 or el34 tubes, or a 100 watt amp with four 6l6 or el34s, is a pushpull amp. Certain assumptions may be made as long as the power output of an amp is known.

Note that a 6l6 model was used in place of a 6v6 because it was readily available. 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. The origin of the power amplifier design came from the schematic below, which came from the 1959 rca receiving tube manual tech series rc19. Symmetrical layout design in signal paths for both channels. Working with data and trying out a few configurations led me to believe that the 5k. As a result, most guitarists and some manufacturers simply refer to the 6l6gc as 6l6. The tube amplifier replaces a solidstate amplifier which was driven by a tube.

There is a computer program that comes with this page to help you. 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. 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. 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. This project is intended to be built as designed and not piece milled with other designs. One was simulating the el34 amplifier shown below while another was simulating the 6l6 amplifier, and the third was crunching on the kt88 amp. This kit employs commonly used pentode 6l6 6l6gc6l6gcr vacuum tubes for the output stage of a class a amplifier with 12ax7 as input stage. 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. Look at the back of any all tube amp, and youll see warmly glowing glass bottles in a variety of shapes and sizes. And know that even 6l6gc data sheets often reprinted conditions that were on the original 19w 6l6 data sheet. Circuit simulation a deep dive into spice tube amp modeling. Maximum circuit values for maximum rated conditions. A clippable solidstate amp of 200250w sounds about as loud as a 50w tube amp for guitar.

The power amplifier involves three stages, two of which use a 12ax7. 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. 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. The svetlana sv6l6gc is manufactured in the svetlana factory in st. 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. The july 63 763 fender amplifier design is considered by most as the high water mark of fender amplifier design. If you have built any of these circuits, we would love to hear from you so send us your comments. 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. Using 6 as a guideline, the following models were used in spice simulation. 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. Singleended classa tube amplifier design and construction. Support either open loop gain or close loop feedback. The phasesplitter is a very critical part of the pp amplifier, and its behaviour is of great importance for the performance of the amplifier.

Assembly manual schematic parts list tubes and applications design simulations. These books gave a background on vacuum tubes and also their applications to guitar amplifiers. Check out our 6l6 tube catalog page for 6l6 tubes we stock. Even though 6l6 tube is used primary in guitar vacuum tube amplifiers, many manufacturers use this tube in audiophile designs. The tad 6l6wgcstr has an blackplate design, gold grid wire, double getter construction, nonoise filaments, and a 1.

The design of this stage takes skill and care as explained in my earlier paper. This is our collection of diy and hifi audio schematics. This style of amp uses two out of phase signals to drive the pair of output devices. Lets start by looking at the simple standard tube amplification circuit that you will see again and again as you study tube amp schematics. Typical operation and characteristics class a, power amplifier, pentode connection. This is a single power amplifier using natural sounding and powerful 6l6gc tubes. 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. 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.

Feb 21, 2017 this is my prototipal tube amp, it has a 6sn7gtb one half of the tube as preamp, and a 6l6 running in single ended. I remember that 6l6 also the 5881 and kt66 can diffuse and 25w 6l6gc can broadcast 30. Basic theory a 21stcentury approach to understanding preamp, power amp, and power supply design. Discover the differences in listening pleasure with the flexibility of various power tubes and output modes. Similar circuits appeared as early as 1951 using a 6aq5 and a 6bh7 vacuum tube. Lets start by looking at the simple standard tube amplification circuit that you will see again and again as you study tube amp. Developed in 1907, the triad vacuum tube quickly became the mainstay of electronic equipment around the world. From schematic to ordering parts to cab design, it is all here and explained in detail. Pspice spice simulations are a valuable tool that aid in the design of tube amplifiers. 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. Download a pdf schematic of the amp wiring, the driver pcb schematic showing components for this build, and the power supply pcb schematic. 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.

Here below are the main features of this power amplifier. Kt886550 compatible single ended amplifier 5th jan 2014 using fladance mp player 8w rms. 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. This design procedure and program works with either single. The tubebased adjustable regulator is based on one in the 1963 edition of the radio amateurs handbook that uses an 807 and a 6au6. At the time philips had already developed and patented power pentode designs, which were rapidly replacing power triodes due to their greater efficiency. I find his tone more defined, more transparent and clearer than those i mention below. Preamplifier consists of a 6n1p tube and is connected to the audio input. Single ended 6l6 hifi pentode preamp amplifier, tube. The following amplifiers have tubes that are not so common today but they can be replaced with tubes that are more easily obtained. The spreadsheets generated for use with this book are specific to the manual.

Lone wolf blues company single ended 6l6 circuitry. Diytube is both shannons small business located in central illinois and a closeknit forum featuring a handful of helpful and prolific members. Output amplifier consists of a 6p1p output tube and output transformer fig. Design my design involves a fourstage preamplifier, which uses two dualtriode 12ax7 tubes. It also results in a more efficient power output which is why a pair of tubes in these amps can produce 65 watts. There is only one tube family that has the right tone, the 6l6 family. This tube is commonly found relabeled by fender and groove tubes to gt6l6b. Being a guitarist who shares that opinion, i chose to design a tube amp of my own. We stock a large number of premium 6l6 tube types in matched pairs, quads and sextet configuration, ready to be plugged in. 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. A 50 watt amp with two 6l6 or el34 tubes, or a 100 watt amp with four 6l6 or el34s, is. 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 project details the build of a singleended 6l6 harp amp.

Octal u f 6,3 v i f c a0,9 a typical characteristic. Close manufacturing specification tolerances and improved processing provide improved reliability and superior sonic performance. I used a pushpullparallel set of 5b854m tubes, which are basically 807 tubes in a slim bottle with a loctal base. Feel free to send us your hifi audio schematics and we will add them here. The tube amplifier replaces a solidstate amplifier which was driven by a tube preamplifier. Biasing an amp requires some knowledge of tube amp circuits and experience with high voltage.