807 tube amp design pdf

Oct 18, 2007 the tube is usually some rare item that the correspondent was lucky enough to find at a garage sale or inherit, but which has never been used in a power amplifier. For class c telegraphy operation at 80 mhz, plate voltage and input should be reduced to 80 % of maximum ratings. Mar, 2014 807 tube power amplifier phinoy itho hehe. Introduction a couple of years ago i met per lundahl of the swedish company lundahl transformers and his father at an exhibition in connection with an audio engineering society convention, and i tried. I dont think i have ever actually seen any data on using 807s in ultralinear. Oct 20, 2010 the base of the 807 is shielded with a bath salts tin from a crafts store. Don allen 807 5933 single ended w volume pot audio. The base of the 807 is shielded with a bath salts tin from a crafts store. Yes, i have dons fullblown 807 amp with 807s, od3s and 6bq7s, and the signature, backlit lightning bolt.

This is fine for el34s, but 807s dont like a grid 2 voltage of much above 300 320. Williamson described the circuit for his eponymous highfidelity audio amplifier pdf, variations of which used. Singleended pentode mode, with primaryside feedback, and. This page is dedicated to the williamson amplifier, which is regarded by audiophiles as one of the great moments in audio history its intent is to present a tribute to the contribution of mr. Building your own guitar amp is a rewarding pastime, but learning how to do it can be time consuming and frustrating sometimes. The 807 was the mostused amplifier tube in history. First of all, i must say that asking for a design procedure is in itself something of an accomplishment, as most solder slingers go about in a strikingly different way. Nice amp and you are correct the 807 is indirectly heated and its actually a 6l6gc with a top cap and different pin arrangement and yes it does have dht character.

The 807 is a beam tetrode vacuum tube, widely used in audio and radiofrequency power amplifier applications. Two variable capacitors in a pi configuration with the coil provide tuning and load adjustment. Singleended 807 tube amplifier i have stated in the past that my mate don makes an amp a month. Modifications and additions include preamplifier circuits and an r. Williamson to tube audio, and to provide information to users and diy constructors of the features, advantages and disadvantages of this amplifier. This entry was posted in amplifiers, tubes and tagged amplifiers by matthias. The drive circuitry of the control grids is not shown i assume perfect.

If the tube to be used is a tetrode, the screen and grid should be tied together to simulate a triode. Starting from this simple supposition, highvoltage regulator was designed. There are plenty of good designs out there showing different audio amplifiers using 807. It all started with my decision to use the less known tube 807, a tetrode whose features and sounds i was well aware of, from a specific diy project with one tube per channel wired in triode made by christos spathopoulos. Similar circuits appeared as early as 1951 using a 6aq5 and a 6bh7 vacuum tube. The power supply choke is a noname 8henry part found in a catalog at a low price, instead of the triad c16a. Beautiful, 100% hand built stereo, singledended class a triodeultralinear, all tube power amplifier using 807, 6bz7 and 5u4 tubes. Download a pdf schematic of the amp wiring, the driver pcb schematic showing components for this build, and the power supply pcb schematic. Possible solution the following idea completely naturally looks. A development of the 6l6 was the 807 a valve that took the basic 6l6 design, but used a top cap connection for the anode to enable it to be used in rf power applications. Williamson described the circuit for his eponymous highfidelity audio amplifier pdf, variations of which used the 807.

I have a pair of those amps and can relate that the 807 is. Manley 15075 sepp 807 monoblock amplifier 1996 manley labs. Calculate the component values and record your results in part 1 of the amplifier design record sheets. Download a pdf schematic of the amp wiring, the driver pcb schematic. If you have worked mine which is set up for 4watts out, you know how nice it sounds and you may be tempted to build one. The 6l6 revolutionized power tube design by forming the electrons into beams and using aligned control and screen grids to limit grid and screen currents. The 807 was derived from the 6l6 audio power tube and has some of its quirks. A 30w tube amp using two 807 power tubes in pushpull arrangement. I have a pair of those amps and can relate that the 807 is an excellent audio amp tube. Singleended 807 tube amplifier diy audio projects photo. First, to be after good output parameters low output resistance and good dynamics, it is necessary to have high. I have used it on a number of rf transmitters and modulators and i thought it was only fair if my hifi audio amplifier uses it too. I used salvaged transformers purchased well below online prices and 807 tubes which are still reasonably priced.

Monoblock amplifiers use only the best available components, with the shortest and cleanest signal path possible. Despite their best replication efforts, the consensus among performing and studio musicians remains that there is no substitute for a welldesigned tube amp. Dogzilla uses a hextet of venerable 807s as output valves v5v10. A model is also available for american 807 tubes, see the modified circuit in. Final amp for 807 transmitter the radioboard forums.

Never touch the amplifier chassis with one hand while probing with the other hand because a lethal shock can run between your arms. How to build the dx811a allband linear amplifier cq. The 807, a vacuum tube for the ages full page reload. It is relatively easy to find introductory information on how to design simple amplifier stages, and it is also fairly easy to find extremely advanced information on complex circuit design, and nearly all of it is. The choice of a driver tube is the 12ax7 which is a common small signal tube. Load line analysis was used to determine the behavior of this stage. The power tube is used in the groundedcathode configuration fig. I used a pushpullparallel set of 5b854m tubes, which are basically 807 tubes in a slim bottle with a loctal base. There is a computer program that comes with this page to help you. The only problem i encountered was with 10 meters and my 350 pf tuning capacitor. In the early 50s stancor chicago standard transformer corporation offered a prepunched set of chassis and detailed instructions using their transformers and chokes to build a williamson amplifier using 807s. Filter capacitors are the unusual 16 f, 700 vdc electrolytic of the handbook design.

Nov 22, 2015 this the first video of many on design and build of an audio tube 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. How to build a tube amplifier rob robinettes car and tube. Dlab 807 vintage tube guitar amp demo hand built powerful machine duration. Singleended classa tube amplifier design and construction. Stereo tube amplifier 807 singledended triode ultralinear. In the summer of 2002 i decided to build a pair of mono block parallel single ended diy tube amps, using the 807 tube.

Designing vacuum tube amplifiers and related topics. Williamson ultralinear amplifier schematics tube books. Both these amps are in ultralinear which puts the screen grids grid 2s at this same potential. The valve type 807 is an indirectly heated beam tetrode designed for use in the output stages of public address equipment, or as an rf amplifier. This the first video of many on design and build of an audio tube amp. Recently added speakerheadphone switch and headphone jack. I am glad about the results because thats a very good way to verify my 6dj8 and 6l6gc spice models, like i tell you. Design of the driver stage is concerned with voltage amplification as well as linearity in order to provide the output section with a strong and relatively clean signal.

Getting all those little resistors and caps in place on the board will make your amp project seem much. How to design valve guitar amplifiers the valve wizard. Dimitrios tsifakis dtsifakis at geemail dot com the 807 has always been my favourite valve. The tube is usually some rare item that the correspondent was lucky enough to find at a garage sale or inherit, but which has never been used in a power amplifier. This little gem has a maximum input of 1012 watts so will typically produce around 4 or five watts of output a vacuum tube qrp transmitter.

The tubebased adjustable regulator is based on one in the 1963 edition of the radio amateurs handbook that uses an 807 and a 6au6. Being a guitarist who shares that opinion, i chose to design a tube amp of my own. This amplifier layout has been carefully designed using a combination of vintage, and high quality components. Being the classic that it is, there is a lot of literature on the 807. Forming the electrons into beams increased the space charge near the plate, which then repelled secondary electrons back to the plate, eliminating the need for a surpressor grid. Subwoofer box design valve amplifier magic eyes circuit diagram electrical engineering vacuum tube electronics projects connection. Attached please find a table of contents for this class. Dogzilla uses a hextet of venerable 807 s as output valves v5v10. Screened cables to the output transformer improved the situation and a 6sn7 driver also helped but still not 100%. Figure 1 shows several pushpull tube amplifiers only the power tubes and the output transformers primary winding. The spreadsheets generated for use with this book are specific to the manual.

The dimensions for l6 and l7 were taken directly from the radio handbook by bill orr 21st edition, editors engineers, div. Heatercathode type used as af power amplifier and modulator and as rf power amplifier and oscillator. This month don has completed an 807 amp based on a schematic designed by matt from the usa and the same as i built a short time back. Opening a tube amp kit and seeing all those little parts can be overwhelming so i recommend you do an inventory of the big parts like transformers, chassis, switches, tube sockets, etc. If you have not been trained to work with high voltage then have an amp technician service your amp. After many years designing single ended amplifiers i have decided to start a series of test about the push pull amplifiers. The funny thing is with only 2 807 the amp played nice but not very loud. The amp is just wonderful to hear and to observe, especially those od3s at night. A homebrew transmitter from the 1960s, updated for today. From audiophile tube amps, to rf modulators to rf linears and classc self excited power oscillators, the 807 wasis there. A ccording to don, he was very impressed with the amp he built for me and decided to build one for himself. 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. It still beats the 6146 in popularity, given the time it was used.

Grid to plate coupling could cause instability in power output stages. A homebrew transmitter from the 1960s, updated for todays. This tube has been described as the valve that won the war, because of its widespread use by the allied forces during wwii. In the early 50s stancor chicago standard transformer corporation offered a prepunched set of chassis and detailed instructions using their transformers and chokes to build a williamson amplifier using 807 s. A tube amplifier chassis contains lethal high voltage even when unpluggedsometimes over 700 volts ac and 500 volts dc. The 6l6 first appeared before the second world war, and was widely used in many applications, especially in audio amplifier, finding particular favour in guitar amplifiers.