Presented here amplifier is a typial single ended based on el34 in the power stage operating in triode and pentode mode selected by a switch and ecc82 in the preamplifier operating as white follower, em84 as a meter and eaa91 as a signal rectifier for tubes em84. Prowess amplifiers offers resources for the guitar tube amplifier builder. El34 single ended amplifier will be get 10w rms by good condition of power supply and good audio out put transformer. Home schematics ella push pull el34kt88 amplifier schematic. If the values of c103 and r107 and r108 are wrong too low of capacitance to bypass bass frequencies. These changes appear in red so you wont have to read through the entire text searching for them. El34 push pull triode connected mono block amplifiers. The driver tube is 12au7 preceded by 12ax7 at the input. Modifications to boyuu douk audio a10 el34 amplifier. With both air tight atm3s 6l6s and dynaco mkiiis el34s, 6550s i prefer ultralinear to triode. The circuit is interesting but i think it is hard to find the tubes. These are what a manufacturer calls post production changes. Posted on june 8, 2015 june 8, 2015 ella push pull el34kt88 amplifier schematic.
This tube amplifier designed in 1953 and worked from 1954 until 1989. Some things, like the actual el34 cathode resistor value, will have to be determined when the thing is up and running, and measurements can be made. El34 tubes, in an ab amp, or similar design, would produce more power, but the 8watts, that this amp produces in triode mode is understandable. The lower end of the range will suit lower transformer impedances, and vice versa. As you look upon the following schematic, your eyes tell you that you are looking at a pentode in a cathodefollower configuration. Stc super triode connectionamplifier a to z and if do you interesting. The amplifier worked from 1954 to 1989, whenever and went off, with an average lifespan of 15 hours a day. I think its the lower bias voltage in the outer pair that allows for swapping 6l6s and el34s without needing to rebias. There are many fine tetrode, pentode and beam power tubes that can be used in triode operation, however care is necessary to avoid applying excessive voltage to the screengrids such as the el346ca7 425 vdc octal and el846bq5 300 vdc 9 pin pentodes.
Schematic diagram e34lel34 single ended amplifier note. I know that pentode is for the 100w setting on my amp and the triode mode is for 50w. Using a conventional, three stage, single ended, power amplifier circuit. On 2002,el34 single ended amplifier made in chile by lagartoschematic. Integrated el34 pushpull amplifier, which can be switched onthefly between triode and ultralinear. After putting the amplifier into operation i found a few changes were necessary to the power supply. I am not known as a person disposed towards hyperbole, but i will start with a startling exclamation. I planned on running el34s triode mode at 430v, a schematic i.
Cag is a path transferring energy back from the anode output to the control grid input, thus reducing efficiency. These specifications are provided asis, with no warranty of any kind. Jca20h with el84 triode pentode switch and schematic. A switch found on some tube amplifiers that changes how the tubes are configured, and reduces the efficiency of tube operation, reducing the power output of the amplifier. I dont think a cj el34 designed amplifier can take other pentodes as direct replacements for the output stage. There are a number or ways to arrange output tubes, opts, and driver stages and nfb. Modify the ul40s2 into a supertriode amplifier vanderveen. El34 wired triode single ended amplifier 4w rms el32 triode connection single ended amplifier transformer are pmf7wsnoguchi transformer co tokyo japan. Discussion in marshall amps started by dioesque, jul 16, 2010. For iht, use a large number of closely spaced filament wires n large, and d small in the program. By trying out several different sets of operating conditions in the computer i could eliminate hundreds of possibilities without playing with electricity. A pushpull triode el84 schematic by thomas martens lowredmoon tube diy asylum. You are free to use the schematics and info to build your own tube gear.
E34ls schematic diagram jj e34lred tube single ended amplifier. Would this mean that the supertriode circuit is not possible in the ul40s2. Interstage transformers splits the phase equally for both el34 to work in perfect push pull mode and coupled the signal from the driver tube to the el34. Placed the amp to triode mode, a truly simple mod with great return. In the triode mode the sound quality was better, but the output power went down to a. Hi i did not mean the el34 is a triode, i was not very clear. Stereo el34 tube amplifier, first test of claus byrith. Theres probably not too many current hifi power amps that use pentode mode, ultralinear is more popular for the reasons statman outlined. El34 pushpull tube amp kit tu8340 adopted semiautomatic bias adjustment system which allows users to adjust the bias simply by pressing buttons even if the model takes on the fixed bias method no need of manual adjustment every time of tube rolling.
Incidentally, although the el34 data sheet claims the maximum quiescent anode voltage is 800v, this applied to current production in the 1960s. El34 triode connection nonnfb pushpull with hashimoto transformers project. Jca20h with el84 triode pentode switch and schematic circuit diagram. Ime with pushpull el34 and kt88 amps with no global feedback changing to triode mode from ultralinear gave a more realistic, 3d sound with the reduced power not a factor. This amplifier was originally featured on the february 2003 issue of the highfidelity audio. A pushpull triode el84 schematic by thomas martens. He built a pp amp using 4x6650 in triode mode, class ab2. Triode connected pentodes article by herb reichert of eddy electronic inc.
I wondering if any of you know if putting on one setting wears the tubes down faster and if all tubes are working in both modes. Suggested by umg creedence clearwater revival have you ever seen the rain official song fortunate son. Original schematic of the boyuu douk audio a10 el34 amplifier. The amps are mono blocks, consonance cyber 800se with the pentodetriode switch. Was wondering if this is not a true triode design what would i gain if anything by purchasing a.
El34jj e34l red tubemini triode wired single ended amplifier diy. Norman koren vacuum tube audio page norman koren photography. On the other hand, many audiophiles prefer triodemode operation and, until. In contrast, my words insist that the output tube is functioning as a triode and that it is configured as a groundedcathode voltage amplifier, not a unitygain buffer. Assembly manual schematic parts list tubes and applications design simulations. Oh i forgot add if i can change between the modes while the amp is on.
Would this be that the trannies have been optimised for ultralinear. Triode mode vs pento mode audiogon discussion forum. I got a marshall 2100 slx 100w, so you guys know what amp im talking about. Enter the foll pathname of the file containing the schematics symbols, except for the. Direct heating sakuma direct heat amplifier system, schematics, direct heated triode dht diy pushpull pp 6v6 tube amplifier schematic this 6v6 amp was built following the pushpull pp el84 6v6 dynaco a410 output transformer schematic. This is the circuit diagram of 35w tube power amplifier with el34. I use cathode bias in that amp schematic coming soon with a 560 ohm. Pentodes connected as triodes 5 one of the principle problems of the triode is interelectrode capacitance, especially between anode and control grid. Kt88 class a amp with universal driver pcb diy tube amplifier schematics ax84. El34jj e34l red tubemini triode wired single ended. Description 2 x 12w tube amplifier with el34 and dynavoice dm6 loudspeakers. Improved vacuum tube models for spice simulations, part 1 improved vacuum tube models for spice simulations.
Most amps i have built have their power tubes screen grid at the same potential as the plate, and then are being considered as triodes. On amps that use the cathode kill style, you must drop the impedance selection down one setting lower than the cabs rating i. This effect is mostly dependent on c ag value and stage gain and is known as. Tube amplifiers, schematics, parts, triode amplifiers. Thus safe and simple bias adjustment is realized a dream feature for tube lovers. Most of the parts are in stock except transformers.
Boy 6dj8 in place of the 6n1p and siemens el34 on triode mode. There are a few minor deviations from the original schematics. Triode connected pentodes article by herb reichert of eddy. On amps that use a triodepentode switch, the load does not have to be compensated when you run it in triode mode. My favorite selction of tubes for this amp are an amperex bugle boy 6dj8 in place of the 6n1p and siemens el34 on triode mode. Details about el34 pp power stereo amplifier pcb 1 piece. Which provides higher fidelity, triodes or pentodes. Ella push pull el34kt88 amplifier schematic diy hifi supply. Do you know how much currentvoltage a pair of el34 tubes delivers in a 3. Ok i just looked at the schematic for one and you are correct. The el34 data sheet shows that a pentode connection with lower plate voltage than a triode connection produces more power 3w more if i remember. Rons audio sound for the regular guy kt77 single ended stereo amplifier.
After many years designing single ended amplifiers i have decided to start a series of test about the push pull amplifiers. A triode tube has a control grid signal in, a plate signal out, and a cathode. An easily constructed highquality singleended 8w amplifier using standard valves and the lundahl ll 1664 output transformer claus byrith 2002. And feedback is not at all about the cleanness, i actually love it when tubes distort just a tiny bit, it sounds extremely agressive to my ear and gives a spatial perception for some tubes, but its about output impedance. However i was surprised how much better the amp sounded in triode, i did this on an el34 50w output stage and. To open the amplifier simulation in the editor, click on the 2x30w el34 tube amplifier tab then click on the green pencil icon in the upper right of the view window, save the file if prompted and then follow the instructions in the schematic. I did ask for a schematic after and they did send me one. The use of a 21, push pull amplifier, schematic, parts list, and some results. Thats also why i opted for triode mode instead of pentode. With both air tight atm3s 6l6s and dynaco mkiiis el34 s, 6550s i prefer ultralinear to triode. I have also included a e34l or el34 or 6ca7 push pull triode connected. There is a subtle difference in sound but i do like the triode mode better. In both instances the triode mode loses resolution and screws up the natural harmonic structure. Single tube el34 triodeulpentode power amplifier stereo pcb.
Now, i suspect that when the mkiv is switched to triode mode it does indeed run the outer tube pair in class a mode, just like the earlier simulclass amps operated. Here is a first draft of the intended schematic, let me know if you have any ideas, criticisms, suggestions or tips on modifications before i start working on a layout. If youre going anywhere near drawing grid current, youll have to lose those grid. This amplifier was originally featured on the march 2003 issue of the highfidelity audio. Reisong boyuu mt34 mkii pushpull rectifier audio hifi el34 hifi tube amplifier. Other single ended el34 designs commonly use between 250v and 400v. How do you explain the old kt66 jtm45s and current replicas that run a highz or lowz ot. Use of these parameters shall be entirely at the users own risk. This driver tube, a 12at7 and the output tube, an el34, pure pentode, are coupled in. Good news, it sounds far better than any amp i have ever heard, by a huge margin. Hello, my name is joe rasmussen and i have an interesting story to tell.
El34 triode connection nonnfb pushpull with hashimoto transformers. I remember when i had my vtls with el34s, it had a switch on the front panel that allowed you to change from tetrode to triode mode without having to modify internally, and would halve the output stage in terms of power. Muzishare x5 el34 x4 vacuum tube integrated amplifier pushpull with remote. The group of tubes in the centrefront are for the phono stage. Heshe is the type of person who buys all sorts of metres and computer software to analyse thd, freq response, linear response, etc.
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