Otl tube amp design book

The start with this little amplifier was the christmas weekends and all spare time i got together with the lack of parts to my power amplifier. The initial intent was to design an otl amplifier that i saw in the back of a bruce rozenblit amplifier design book. This new design to reduces cost without any sacrifice in performance. That is you want to amplify voltage as much as possible. Review by dick olsher even 60 years after the concept gained some traction, the notion of an output transformerless otl tube amplifier still seems mind blowing.

But the sound is better than any other amp ive had by far. Output transformerless otl is a type of vacuum tube audio power amplifier, which omits an output transformer for the purpose of greater linearity and fidelity. Vacuum tube audio amplifier kits, otl amp kits, tube phono and line level preamp kits, low cost. Please practice handwashing and social distancing, and check out our resources for adapting to these times. Instead, otls use one of two primary methods for output stage coupling. Transcendent sound single ended otl amplifiers user. Discover stepbystep how to design phase inverters and power amps to achieve your specific design goals. Tenor tenor audio celebrating 20 years of michel vanden. Building valve amplifiers tube electronics for you and me. We also have a world class tube line level preamps and tube phono preamp. Son of beast otl vacuum tube amp transcendent sound. Fleming used the principle to design the diode, the first vacuum tube. When you hit the above link you will probably understand the difference. With precious little valve electronics in the book, it certainly is not the most up to date and comprehensive vacuum tube design book currently available.

Our otl amplifiers give a sense of musical rightness, together with a realism that reveals the unique qualities of each recording. By stating you made the first reliable otls does indicate that some or all of your predecessors were in fact, not reliable. Diy audio books and manuals speakers, vacuum tubes, electronics. Given the 72ohm load, the solidstate power amplifier was voltage limited. This gives some unique features like giving more power the higher the impedance, the tube may or may not color the sound, and theres a high output impedance, so it doesnt pair well with low impedance headphones. The acronym otl refers to a tube amplifier that is output transformerless. It is the foundation of our success and the reason tenor amplifiers sound so perfect and become the last amplifier you will ever want or need. Valve and electronics department, 1957, 126 pages thanks to eric santanen. Output transformers are large, heavy, and difficult to manufacture.

First of all i want to really thanks bruce for his work, passion and for the design sharing. We get a lot of people asking us for diy audio and loudspeaker book recommendations to get them started in the hobby. The 6c33c is today probably the best tube available for otl s, it is a pure triode, it can pass high continuous currents and it is relatively cheap and easy to come by, for more info about this tube see. Welcome to my vacuum tube audio page, which i dedicate to the reader who seeks an indepth understanding of amplifier design who wants to learn the factors that contribute to audio quality who doesnt buy the myths of the highend marketplace, where old designs enhanced with premium components and dressed up in impressive packages command astronomical prices. Dec 30, 2006 otl amplifier design revisited the last schematic i posted held a few typos, which have been corrected, as shown below in redrawing the schematic, however, i realized that topology was just too big a jump for many, and that i needed to work my way up to this schematic in stages, starting with the underlying otl topology without the crossovernotcheliminating aspects of the circuitry. As i have already said, it measures very flat, and harmonic and intermodulation distortion are both exceptionally low for a tube amp.

Feb 1, 2017 otl tube amp amplifier production schematic. Otl asylum otl, output transformerless amplifier user group. This may be considered a beginners guide for tube audio design if you have extensive electrical experience. I would say that the power supply solution chosen to drive the output tubes in the otl by unknow japanese company and in the otl by yozo matsuoka from mj 199511 looks a bit strange to me, because it is designed around is a voltage duplicator where there is. Qtron pa12 otl tube amplifier delivering the full promise of otl. In order to convert from the high voltage of tubes to the low voltage of a speaker an electronic device known as a transformer is used. Usually when you design tube amps you design with regard to common cathode cc. This results in significant cost savings if there are no output transformers in the design. The tube based otl amplifier poured 2a peak into the 8ohm load, which into a 72ohm load, results in voltage drop of 144vpk, which in turn equals 144. New york audio laboratories futterman otl1 power amplifier. Otl tube amps are peculiar, uncommon designs that go to great lengths to avoid using ots. He calls it zotl to differentiate it from otl, but the result is the same. It seems like a beginners physicselectronics book that suddenly has a couple of exotic tube amp circuits bolted on the end.

An approach to audio frequency amplifier design, g. In that case transformer coupled preamps are the uncommon design. This does not mean that the otl 1 is colored in any normal sense of the term. Just to be clear, im not trolling you, or your company, just answering the question in the thread title, whats your otl tube amp experience and suggestion.

The tubebased otl amplifier poured 2a peak into the 8ohm load, which into a 72ohm load, results in voltage drop of 144vpk, which in turn equals 144. New 9718 a hybrid ss driver class a2 dht amp a 50 watt monoblock version of the engineers amp. I suggest to read this article by turner audio, has a lot of information regarding otl amplifiers. Some of them are long out of print, and can only be obtained from used book sellers, although they are occasionally seen for sale on the internet. My passion for highend audio design always remained and my years in television repair introduced me to horizontal sweep tubes, which became my output tube of choice in single ended, push pull and otl amplifiers.

Otl amps sound great and a lot of them produce good technicalities compared to other headphone amps of similar price. Ier i know this is a dc approximation, 32 volts16 ohms approx. Qtron pa12 otl tube amplifier delivering the full promise of otl technology. Guitar amplifier power amps helps you get the most out of it. At any rate, if i dont find a suitable non otl amp design that i like, i may just sell off the entire lot of 6080 tubes. Mcalister audio vacuum tube power amplifiers, high end. Transformation of the highimpedance and lowcurrent tube plate circuit into the highcurrent and low impedance needs of a. Words alone cannot reveal the otl tube amp experience. The amp requires the most neutral preamp and sources, and works well with tube or solid state. Until 1954, julius flutterman first came up with his patented otl design which aroused the audio electronic world op iron can then be disposed. Better to use a 32 ohms speaker, the amplifier will deliver 80vpp or 28vrms at 0. But he does mean if you spend a crap load on a tube amp then its better to just go with a set amp, have slightly more power, more compatibility, and better sound for the same price of an uber expensive otl. Otl output trasformer less tube amplifiers audio design guide. Transformation of the highimpedance and lowcurrent tube plate circuit into the.

Note more than likely it will lose you a few times, and like any good referencetraining material, rereading it a couple of times you really see how what you didnt understand the first time through starts to make sense. This type of tube in many respects is superior to the standard array of audio output tubes currently used some of the best vacuum. Hifi el84 vacuum tube amplifier integrated class a singleend stereo audio amp. The new otl designs on sale here from transcendent are low power in comparison to the old one, so im quite confused. The back cover says that the book is the most comprehensive and up to. Originally announced in 2010, the crack is an affordable tube based headphone amplifier kit offered by the bottlehead corporation located in poulsbo, washington state, usa. Projects provide stepbystep design procedures, equations, schematics, parts lists, and photos to assist the hobbyist in construction. The transcendent otl 80w diy transcendent sound forum. Otl output trasformer less tube amplifiers my consideration on problems of each design. In a word, amplifier speaker interaction effects are especially unpredictable. Is this the kind of current required at 150 volts, for each 150 volt supply. Otl amplifier celebrating twenty years of michel vanden. This is very much cheaper than other otl amps or good quality conventional tube amps. This inexpensive tube amplifier kit has been available for a number of years now and makes for a nice little tube amp.

Following is a list of must have books for the serious tube amplifier designer. Regular tube amplifiers have very high voltages in them and by contrast most loudspeakers are low voltage. Im really interested to build a the transcendent otl 80w from audio reality book, but im wondering if it does have any sense nowaday. After design of layout i ordered the necessary parts. There are a lot of books on the topic and naturally we cannot go over all of them all. Diy vacuum tube valve amplifier projects hifi audio.

The company was created by the president for life dan doc b schmalle in the mid1990s, and primarily offers diy tube audio kits for both headphones and home stereos. The otl had two 5,000 watt regulated power supplieswhich are testament to ted hamonds engineering genius. A really good otl design makes your transducers sound like they are directcoupled to the music, and that is precisely what the feliks audio euforia does to your headphones. Audio asylum otl asylum otl, output transformerless amplifier user group.

Circuit simulation a deep dive into spice tube amp modeling. Beginners guide to tube audio design book this guide will assist the novice in understanding vacuum tube technology and prepare the reader to build vacuum tube amplifiers. He specializes in otl no output transformer amplifiers that produce maximum fidelity. Tenor makes hybrid tube amps an update to their hybrid 300 mono blocks i owned briefly in 2004 now.

Conventional vacuum tube amplifier designs rely upon an output transformer to couple the amplifiers output stage to the loudspeaker. It is silky smooth yet possesses uncanny detail and three dimensional imaging. Conventional vacuum tube amplifier designs rely upon an output transformer. Basic information on power supply design and function. Mr dakesue in japan was the first person to design a 6c33cb otl power amplifier. I want to add that this is only 1 12 wpc but it sounds like 5 wpc. A bibliography of must have tube electronics books. Conventional vacuum tube amplifier designs rely upon an output transformer to couple the amplifier s output stage to the loudspeaker.

Diy otl tube headphone amp kit pcb, case, extras aikido wcf 6sn7, 6bx7. Such amplifiers are commonly called otl tube amplifiers. I see no reason to avoid otl for reliability reasons anymore. My amp shown above 10 wattschannel by berning no longer in production, alas is singleended, and in actual use is like an otl type amp the best of both worlds. I discuss why why you need so many tubes such as 6as7, 6336. The dynamics of power amp distortion create the heart and soul of an amplifier. I was aiming for the audio gdhe9 but have reconsidered.

Its basicly an amp that doesnt rely on transistors, and its the tubes who make all the amplifying. Amp options my otl design offers several solutions. Below is a short list of some of the books we have and can recommend as good resource on the subject. Tube amp design wikibooks, open books for an open world. Weve all seen the classic gec amp schematics, but heres the whole book. Qtron pa12 otl tube amplifier delivering the full promise. Our designs emphasize simple, trouble free operation. This guide discusses all relevant aspects for an integrated pushpull vacuum tube amplifier design, including the power supply unit. This form of otl design carries the futterman designs pioneered by new york audio labs one step forward. Anyone that uses vacuum tubes, from the hobbyist, the musician, to the design professional, would benefit from tubes and circuits. Here you will find vacuum tube based amplifier, preamplifier and headphone amplifier kits, speaker kits, finished high end tube audio products, reel to reel tape machine upgrades, parts, and one of the finest support communities on the web. Audio engineers and designers have been trying to build otl amplifiers since the 1950s, but they met with only limited success. Early otl amplifiers and even modern otl amplifiers based on these early designs typically have between 8, or 16 or more output tubes per channel.

As a rank beginner, i bought this book to help me understand amplifier design so i could better diagnose issues with my tube amplifiers. The author systematically steps through single one stage amplifiers, simple gain circuits, negative feedback, output stages and transformers including single ended types. Seventeen amplifier designs ranging from 3 to 1,100 watts are presented, along with tube data and design considerations. Beside that, el34, el84, and 12ax7 vacuum tubes are used in many practical examples, to design the various parts of the circuits and to. For those who use high efficiency speakers of 94db or better you will be rewarded with rich natural sound. Apr 03, 2019 tube amplifiers with output transformers are typically preferred due to the flexibility of headphone pairing options for the owner, however the otl design has a few significant benefits. At the beginning of the year, i found this interesting scheme of tube amplifiers on a forum and decided to make it.

How do you really design an otl amplifier with high reliability. The lack of an output coupling capacitor extends bass response to less than 0. Feb 01, 2017 feb 1, 2017 otl tube amp amplifier production schematic stay safe and healthy. Do they sound different and why people want tubes duration.

The data of this tube was much better than anything made before in the west and sanei of japan imported some 6c33c tubes for audio application in 1997, renaming them ec33c for the japanese consumer. One day i did think about building the otl amp, but i later found out that these amps are very finicky and you do need quite a few tubes to get the job done. Our tube amps and preamps are renown for their extremely low noise and musicality. In addition, five projects are included that you can build. Otl preamps are basically almost all common hifi tube preamps. Tubes and circuits by bruce rozenblit inner magazines. It is just the actual leg names that differ a mosfetjfet from a tube model. Tubes and circuits by bruce rozenblit on inner magazines some people. These amps took the world by storm as the premier tube amplifier of its time and gave tenor chief engineer, michel vanden broeck, a well served place in audio history. The otl 1 is probably the best amp available for the tube fanatic seeking the maximum possible emotional impact from recorded music. If we avoid the work of drawing load lines on a pc screen, or exercize book, then rla class a1 load for.

The basic steps of power amp design 19 the commoncathode amplifier 19 the dc operating point 20 using triodeconnected curves 21 vacuum tube response to ac signals 23 cutoff and saturation 23 setting the dc operating point 25 the ac load line 26 optimum load line for pentodes 30 screen dissipation 33 maximum power and headroom 35 dc grid bias. All of the theory is put to use and made practical in the project chapters. Because it is not easy to design a good otl circuit. Another problem was how to realize a symmetrical output stage when tubes do not come as complementary npn and pnp pairs as with transistors. Great book to get a good grasp of the ins and outs of tube audio design. In my amplifier i have used a 200va power transformer per channel. We are also producing hightech otl outputtransformerless amplifiers and custom made to extreme high satisfaction guitar amplifiers, including tube guitar otl amplifiers. Such designs ensure that the purest, distortion free signal reaches the loudspeakers. Back to otl designs for us tubeloving folk, the ideal tube power amplifier would be both output transformer and coupling capacitor free, the. Perfect 35 year old vintage otl tube amp by aitos duration. Linear tube audio uses unique technology, superior quality, and unmatched value to create worldclass amps that sound like no other at a price normal people can afford. Such an amplifier would generate between 1200 watts and 1800 watts of heat, which is about as much heat. The most up to date vacuum tube design book currently available.

Theory, but also our listening panel told us that a well built output transformer less otl amplifier is able to approach the live sound more accurately than any other amplifier, transistor or tube. Push pull vs otl vs set tube amps super best audio friends. This page is about otl amps, strengths and weaknesses, and why not having an output transformer may ruin good music. The other speaker design thats often teamed with an set amp is the singledriver speaker thats close to 100db efficient, has no crossover, and has very easy impedance curves. I have the berning zotltype, and i think it may be the best design of all amps ever. Basic theory a 21stcentury approach to understanding preamp, power amp, and power supply design fundamentals of guitar amplifier system design a structured methodolody for crafting an awesome guitar amplifier. With its very modest price tag, this kit is an affordable step into the wonderful world of vacuum tube audio. Only a tenor amplifier renders the music the way it was originally recorded. Otl amplifier design revisited the last schematic i posted held a few typos, which have been corrected, as shown below in redrawing the schematic, however, i realized that topology was just too big a jump for many, and that i needed to work my way up to this schematic in stages, starting with the underlying otl topology without the crossovernotcheliminating aspects of the circuitry. Whats so irresistible about a singleended triode set amp.