Otl tube amp schematic In that perfect world in our dreams, fantastic-sounding 1,000-ohm loudspeakers are both cheap and common, allowing us to build fantastic-sounding and inexpensive OTL my latest project was the Trion MK2 SE EL 34 tube amp and this amplifier works without problems since a year now. Next steps : - reduce the slope of the square wave tops at low frequencies. The 6AS7G family OTL headphone amp is everywhere these days. Given the high current, both HV regulators and the power tube loads are mounted on external heat sinks. This page covers all things related to my EL34 amp. đ This assumes identical output tubes, which won't be the case when I build it. The TA-66 adopts a 6N2 tube for preamp function making vocals sweet and exquisite, and a 6N5P buffer tube creating soft, charming audio. How-ever, this concept is not easy to realize in practice, otherwise there would be more of these around. 6C33C runaway makes it really poor choice for the first tube project. I recently finished the build of my third OTL headphone amp. Check out the info on HeadWize - Project: The Morgan Jones Mini Tube Headphone Amplifier by Chu Moy since the original Headwize site is down. There are some really nice sounding tubes not much more expensive like EL84 and the amp will have output transformer to protect valuable hi eff speakers. The subbass and upper treble become less recessed and the 6XX sounds like an overall more complete, fully fleshed-out This article from respected author Ari Polisois deals with a single-ended amplifier with enough power to drive even the most difficult speaker systems - delivering 50W per channel. Search titles only WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES. However the schematic is short on a few values like the plate choke and supply voltages. Further details of this output stage of this amplifier are given on the OTL Amplifier Output Stage Schematic web page. The 6XX especially transforms over its performance with solid-state amps in a similar price range. The distortion looks very low. In my design the 6336 has a steady state tube surface temperature of about 274°F (135°C). Home. Above is the revised amplifier schematic. Nothing new, OTL topology is well known for headphones, I've bough the BH Crack multiple times, the ultimate commercial OTL amp, the Apex Teton and I've designed and built around 4 OTL amps for my use. I expect less but I expect at least 150 watts. It has a considerably simpler power supply arrangement than many OTL designs, which makes construction easier. View Download Category. OTL Vs SET Tube Amplifiers. 1 KB · Views: 1,014 poynton. Schematic by Bruce Rozenblit (Glass Audio 1990). Information on Fourier Components tube OTL amplifiers. The sound of this version is very ârealâ and so detailed that you can hear the quality of the My OTL amp output stage can be configured to use 6c33cb or 6c19p, each has it own PCB for the output only where everything else is same. and the 6AS7 is popular for building OTL amps, you could try that. 6KD6 eats a whopping 6. Berning amplifiers using the ZOTL technology exceed the performance of traditional OTL tube amplifiers by properly matching the tube impedance to that of the speaker. I've attached a schematic of my own take on the 6AS7 pp idea. 3V 2. with 6922, EL84 and the monster 6C33C and that amp. The following schematic shows such a Since output transformers are expensive and I'm pretty much a broke college student at this point, I'd like to put this transformer to work in a DIY OTL amp using parts I already have. Specifically, this is an Aikido input with vantage of a DIY amplifier is that you can adjust the feedback to suit your own taste. top of page. The tube selection for OTL is limited, the high GM low place resistance requirement leaves mainly PSU series pass tubes e. Cant afford OTL as I only have 4 of the 6AS7G tubes. The tube amplifier circuit utilises 12AU7/ECC82 input & 6080 triodes and is output transformerless (OTL) and should pair nicely with the high input impedance of my Sennheiser HD6xx headphones. Tube Amplifier Schematics (Archive) /6SN7 OTL schematics? I only want a few watts, tube count is of most importance not power and I need to SE/UL. I have not made such comparisons, however. and a good push-pull tube amp with output transformers, as far as its tonal quality is concerned. đ I'm just about done with a revised M-60 signal-path schematic that includes the manual-adjustment bias/DC-offset circuit; I've altered the circuit to provide sufficient adjustment range to accommodate the 6AS7's as well as a number of the other output-tube options being discussed in the thread After a great deal of work and learning I gave birth to a beautiful baby amp Below is the schematic and parts list, and a bunch of photos. tube amp schematics Only one small limitation. 1) OK, apparently I experienced a Homer-Simpson-esque "Doh!" moment when originally searching for appropriate off-the-shelf power-transformers for the M-60 mono-block project. You show an op-amp driving a transformer directly. g. No flabbiness or looseness in cone displacement. It also says heaters are 6V at 5 Amps. The input amplifier is configured as a conventional pentode voltage amplifier stage. New posts Search forums. Review Index. A quick explanation of the amp channel schematics: One half of V1 is configured as a standard triode voltage-amplifier stage, Resistors R2 (42k) and R3 (750 Ohms) set the operating conditions, and resistors R1 (1M) and the 100 Ohm grid stopper resistor act as the input, the input signal appears on pin 1 of V1 amplified and inverted, pin 1 of V1 is directly coupled to 6SL7 / 6V6 GT class A OTL headphone amp SOGNO. I used, NOS Soviet electronic tubes, the output tubes are 6N13S (6H13C) r Eight ohms is a horridly-low impedance for any tube to drive directly. Best sounding amp ever~! 12AX7 x 2 , 6SN7 X 4 tube driver stages in the front not shown. The input signal is V2 - a +/- 20V (40V P-P) 1kHz sine wave). Only one small limitation. AMP OPTIONS My OTL design offers several The following passive circuit was designed for an OTL power amplifier that used many parallel output tubes and was meant to drive 8-ohm loudspeakers, but the same topology can be applied to our little 4W OTL headphone amplifier. htm I've got plenty of octal and miniature nine pin tube sockets lying around, along with sizable stocks of electrolytic caps, rectifier diodes, orange drops, and resistors. 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. power rating: 0. Power Supply, Power Stage I have an DIY amp inspired by Rosenblitz´s SE OTL. It does work, though not very well. Also corrected value of R7 and fixed spelling of DCC90 name for V1 tube in What tubes for a OTL tube amp? Thread starter M-60 OTL Power-Supply Schematic (v1. A 25W OTL Tube Amplifier tubes By Tim Mellow FIGURE 1: 25W amplifier circuit. In short, the top and bottom output tubes cannot see the same magnitude of input signal, save for the special case of when the output stage is driving a near-zero-ohm load. Schematic by Andrea Ciuffoli. I've decided I want to build an amp based on JJ's version of the EL509 tube. 5 Amps. Low Voltage Vacuum Tube OTL Audio Amplifier By Usagi Electric. 6AS7G, 6528A. You can read more about this on Bridged and paralleled amplifiers - Wikipedia I added cathode resistor to raise the bias swing and to reduce distortion, grid stopper resistors and adjusted the coupling capacitor values for lowest load. OTL Vacuum Tube Amplifier. I've got plenty of octal and miniature nine pin tube sockets lying around, along with sizable stocks of electrolytic caps, rectifier diodes, orange drops, and Here is another amplifier I designed. It changed my view on the whole tube amplification thing. There are hundreds of pages of Tube amp information on my library page. The design by Bruce Rozenblitz published is GlassAudio back in This key point explains why I use the battery symbol in the Circlotron schematics, although a battery not likely to ever be used in an actual Circlotron. The result was a flat sounding amp, lifeless, and that was the reason to build the other one. Links. Transcendence, Graff. Aspencore network. Those running OTL amps are probably ready to replace the tubes regularly. Tube lineup is currently Another Completed OTL Headphone Amp. In the schematic, R6 is the 8-ohm speaker load. In the schematic, all the cathodes are shown on the bottom (the little hat shape signifies the heater filament), grids in the middle, anodes on top. Misc. Building, troubleshooting and testing of these amplifiers should only be 6as7 Otl seen this schematic looks interesting-any opinions? Attachments. Joined: 14 Feb 2010 7:13 pm Posts: 720 Location: Lisbon, Portugal Looks very good mate! Strange to me The amp shown at the top of this article is an optimized Morgan Jones amplifier (without feedback) built by Bryan Ngiam. Inherent offset voltage in the op-amp inputs, amplified by the circuit 222 WATTS!!! I'm showing 222 watts of power into 8 ohms. 6C33C is a voltage regulator tube not audio tube. John Broskie of tube cad journal has written a lot about otl s; highly recommended! Since you have several very good headphone amp implementations I was wondering if the one you posted with the C3g is your favorite of all. Figure 1 is the schematic for the original Morgan Jones amplifier. I want to use design by Hans Beijner. Circlotron Amplifiers Once Again We near the Tube CAD Journalâs ten-year anniversary and during that near decade I have written much on just about every tube-related topic: a veritable omnium-gatherum of tube technology. . However, for best performance matched tubes are recommended and are available at a fraction of the cost of modern output tubes For some comments on how reliable this circuit and these tubes are, go to 6C33C-B OTL amplifier reliability. With 10 ohms under 15 6KD6 the plate current is on the order of 150mA each, 2. Building, troubleshooting and testing of these amplifiers should only be Do either of you gents have the schematics for the OTL's you discuss in your responses to my post? I will pot my marked up schematic in a few hours. They do not sound like a transistor amp. I've been thinking about OTL amps for headphones a lot lately, inspired by the MJ/6N1P post a few weeks back. I know all the drawbacks re parts and heat etc and don't mind. 6c33c-b otl amplifier - background and otl circuits, Introduction the purpose of this paper is Otl amplifier design: the broskie otl - tube cad, Otl amplifier design There something wrong with the schematic. next. 5% THD if bias @ half HT (+125V), then if only 1 to 10V is required to drive the hp. the extent of my electronics education and ability to read a schematic is from undergraduate intro This is actually a quite significant heat load to be concentrated in one tube. Class A output stage operation. 26 March 2008. Berning amplifiers depart from traditional OTL amplifiers in that they do not require a large number of hot power tubes to supply adequate current for driving speakers. DESCRIPTION. The Brazilian OTL power amplifier requires four power-supply rail voltages: +420Vdc, +140Vdc, -140Vdc, and -280Vdc. Budget 300B Amp; KT120 Monoblock Amp; EL34-6SQ7 Amp; KT88-6EJ7 Amp; 47 Globe Tube Amp; 6BM8 Amp; What is the minimum number of tubes I would need in an OTL design? I am okay with low power output of 1-2 watts per channel. Frank, are you willing to share your Zotl schematic? I downloaded the patent and I get it, a bridge circuit FYI, the Darkvoice 336se is a popular tube headphone amp from China. OTL amps will not be able to drive speakers whose impedence drop much below 4 ohm. I have designed and constructed an OTL headphone amplifier based on the 6GF7 (novar equivalent to 6EM7) which is a dual dissimilar triode originally used for TV vertical oscillator and output duty. Let's just check the datas for my U-OTL6080 : 1 - For 10WRMS output, the pair of mono blocks draws I've heard the BAT PSE tube amp which uses the same tubes but only for a very short time I have a schematic of a PP 6C33C amp. It includes schematics, the BOM and links to videos. PHOTOS . Dear all, I'd like to build my very first tube headphone amp. Do you have a final schematic to share? Thanks, And it is rather satisfying to build a tube amp without output transformers. I also didn't need a lot of power output - perhaps 1-2 watts. Posted: 24 Nov 2012 6:41 pm . Now the tube itself is designed to handle this without issue, but it gets fairly warm. 3. In order to have a true tube sound, I changed some parts of Waardeâs original design, especially in the power supply. About. 2020-09-27 9:03 pm #5 2020-09-27 9:03 pm #5 Mine has almost none. Output tubes have to be replaced frequently. The amplifier is a fully DC-coupled OTL (output-transformerâless) and OCL (output-capacitorâless) design. Amp schematic amplifier tube ended single se diyaudio which. Scanning the complete and very technical manual (including parts An OTL amp with only a single output tube. Or A quick explanation of the amp channel schematics: One half of V1 is configured as a standard triode voltage-amplifier stage, Resistors R2 (42k) and R3 (750 Ohms) set the operating conditions, and resistors R1 (1M) and the 100 Ohm grid stopper resistor act as the input, the input signal appears on pin 1 of V1 amplified and inverted, pin 1 of V1 is directly coupled to There were ideas of a simple single end amplifier based on the 12B4 and I even had one running to the Levinson schematic. The acronym 'OTL' refers to a tube amplifier that is Output TransformerLess. Also, do a serch for a site called K-amps. The Video: I wonder if there is any real reason to even dabble into something like this because Reviews. The plate voltage of the upper section of the 6N6P is indicated as 355 V. This week's blog entry is dedicated to Steven Key. Input options are either switchable line level analogue or USB digital. It uses a CCS loaded LTP followed by a futterman output stage with LED bias and is heavily influenced by the Cavalli Audio Bijou design. They are extremely long lived and reliable. 5/25/99: Ole W. Skunkie Designs. Two years ago I built a pair of "Statements" loudspeakers from the Hobby Hifi magazine - 95db efficiency, two ways with a 15" PA Monacor speaker and a This looks like a partial schematic. Our tube amps and preamps are renown for their extremely low noise and musicality. The result, as the author Well the noise level is very low so that is very quiet as claimed. At low volume, all amps sound clean, more or less (well, depends on the amount of This is a continuation of Impressions of the EL509 tube. I wonder if anyone could help to contribute some schematics of amps using 6AS7G as power tubes and 6BM8 or other tubes as drivers. 6c33cb use 24V and 6p19p use 120V for heater in series. Dickie Jr & A. 85 Amps each, so 15 of those and the 12AU7 is just over 43 Amps, somewhat more than the 5A noted on the plan. that is still very good bias point. One night, he was contemplating the idea as he went to sleep, and in his dream he saw the full schematic solution that told him how an OTL should be Based on the schematic in your link I have simulated it based on your request on parallel tube or amp. Most tubes want to work at 400-600 volts on the plate, an idle current of 50 mA and see a ADM 780 and ADM 1540 Schematics AKG C-61 Tube Mic User Manual and Schematic API 312 Mic Preamp Schematics, Brochures, Pinouts, and Transformer Information RCA OTL Amplifier Schematics Universal Audio BL-40 Limiter Schematics Universal Audio 175a, 176a and 177 Schematics Urei 527a Manual and Schematics This reduces the power consumption of the amplifier to 140 watts, a fraction of what most OTL amplifiers draw. I know that if you look on the DIY section of this site, under the amp section and projects, you'll find a link for a guy named Andre C. I've just finished building my third OTL amp this weekend; a design by Tim Mellow that appeared in Audio Express in the February issue. Monster power supply also not shown. 2Vrms (3. The tube amp is just as punchy (a benefit of OTL) and the bass is very full and round, especially when using crossfeed. This design is using a lot more current (10mA) on the 12at7 than most people do (2-5mA is typical) and is plenty of current to drive a 6v6. One design uses 1682 triodes for the output and the other uses WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES. He has an awesome site with tons of tube and transistor amps. The Original Morgan Jones Amplifier. I've found that the best working point for this tubes are 10 ma for the 6N1P and 22 ma for the 6N6P. Budget 300B Amp; KT120 Monoblock Amp; EL34-6SQ7 Amp; KT88-6EJ7 Amp; 47 Globe Tube Amp; 6BM8 Amp; The Crackatwoa is an upgraded model of Bottlehead's popular DIY Crack OTL headphone amplifier with a larger power transformer, shunt-regulated power supply, multiple inputs, and optional addition of a Bottlehead's TwoQuiet stepped attenuator. And another version of this amp: Tube headphone amplifier circuit otl amp schematics diagram diy ciuffoli schematic vacuum valve google amps level top andrea headphones electronic Tube ended single schematic se Amplifier schematic cat amp ratbag audio. From the schematic they appear to be ECC83. The Tube amp Library of information Click the link above for Tube amp info, Schematics, Board building information, Projects, Mods, Transformer diagrams, Photo's, Sound clips. Fourier Components OTL Amplifiers The following schematic was extracted from a Fourier Components Sans Pareil Mark III, serial number SAN079501L. In the Futterman patent, he cites 60dB negative feedback, which is amazing for a tube amplifier and impossible OTL = Output Trasformer Less Tube Amplifiers My consideration on problems of each design: Ciclotron balanced design problems (type 1): Schematic by P. Perfect for audiophiles seeking the ultimate 143 Tube Amplifier Schematics (OTL,211,6080,300B,VT4C) WW - Free download as PDF File (. DIY (Do-It-Yourself) Discussions It My OTL tube amps can get close to this power level, but the problem is that the K1000's don't sound very good unless they're driven with a really low output impedance. 4V heater supply voltage. Building, troubleshooting and testing of these amplifiers should only be Words alone cannot reveal the OTL tube amp experience. An Output TransformerLess (OTL) amplifier for use with high impedance headphones that comes as a DIY kit. This is bad practice. 8+ amps at 120 volts. Fifteen 6DK6 plus a 12AU7 is 16*0. Checked links from Svetlana Tech Bulletin (by Cyrus Brenneman) but links on circuit was dead. 700V supply for triodes designed for 250V max, -213 V on the grid (currently shown as plate) of output with -13 on the cathode . They do not sound like a conventional tube amp. The loudspeaker (a 5" mid-bass) sure moves greatly on bass and percussions but is tight-handled by the amp, like a good OTL amp would do. So in schematic for Tim Mellow OTL you can replace 1x6c33c with 4-5x6p19p. Thread starter iMickey503; Start date Feb 24, 2022; iMickey503 Senior Member. fr/otl3w_eng. This tube has an octal base (no plate cap). The design by Bruce Rozenblitz published is GlassAudio back in . This is a project that quickly became WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES. Power Supply, Driver & Bias. Tube replacement is easy and matched tubes are not required as the servo adjusts for unmatched grid bias. 6as7_futterman_otl. Macovski (June 1954) 6336A PP (Taki OTL) reg. NEW Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra I have interest to built an OTL (output transformerless) amplifier using 6C33C tubes. Tubes and Circuits provides all design procedures and equations necessary to allow readers to create their own designs. prev. No Click on image to see enlargement . Some design constraints for this amp: EL509 output tube, triode strapped, push pull configuration. Joined 2005. by Kurt Strain The tube headphone amplifier in figure 1 is a high current mu follower, with a 12AU7 cathode follower driven by a 6CG7. Thread starter diesel_tech; Start date 2009-03-21 2:46 am; Status Not open for further replies. Based on those I am about creating a PCB board with the dimensions of 230X140mm which will Having built a number of vacuum tube output transformer-less (OTL) amplifiers in recent years, it seemed as though it might be a good idea to try. Both sections of each tube are paralleled to minimize noise. Is that a Cathode Follower output? What did you use for the current source for the 13E1? Solid state, or a Choke? Can you post a schematic, please? Thanks! M. The tube-based OTL amplifier poured 2A (peak) into the 8-ohm load, which into a 72-ohm load, results in voltage drop of 144Vpk, which in turn equals 144²/(2 x 72) = 144W. gif. When clicked the schematic you posted shows a âschematic not finalâ message in the lower left corner. This is the project page for our 12AX7 EL34 production tube amplifier build. Joined Jul 19, 2021 Messages 404 Likes 669 This is my attempt to build an OTL tube amplifier according to the Japanese scheme. You really need to change every cap in the amp as these are at least 40 years old now. Without a transformer the output tube sees the impedance of the headphones so you are then limited to larger current capable tubes or paralleled tube sections (if the tube has two triodes for example). Some very interesting amp schematics on that site. EL34 can output 120V at 1. Second one is the driver stage with cool switch feature if you want try different tubes . This page covers all things related to my 6SQ7 amp. The Amplifier Designs. OTL CLASS A TUBE AMPLIFIERS Home. It is surely not as beautiful as the ones made by tubeelectron and BuzzK but it works very well (and I don't have children or pets). we would be lucky to get 20% in an OTL. What follows is a cluster of schematics on a two themesâeach with the 6AS7/6080 as the intended output tube, with each 6AS7 triode Explore the xDuoo TA-66 High-Performance Tube Amplifier, featuring 6N2 and 6N5P tubes, point-to-point wiring, and a step-by-step volume potentiometer for unparalleled audio fidelity. The amp has that tube âsweetnessâ, but I have to say that the NAD The company that made the OTL amplifier and the technician who tests the amplifier do not care, but the music lover listening to the amplifier will care, as the amplifier will stumble while playing music. Those tubes such as the 6AS7 and 6080 were originally designed for higher current and so have lower As speakers move up on the efficiency scale, the need for high-power amplifiers declines. Nothing sounds better than an OTL. However it ran really hot and showed a lot of hum, so it was scrapped. 1% and the phase margin was no worse. It still works fine at, say, 3. Power: 35W/16Ohms, 25W/8Ohms, 15W/4Ohms. The splitter tube is label as a typo and the small 0. pdf) or read online for free. There is too much 60 Hz hum, I believe due to filtering issues in the power supply and I need better 6082 tubes. this schematic is loosely based on the better known Morgan Jones ECC88 OTL headphone amp which is an improved version of the famous Earmax amp. The GM 200 is completely Italian in origin, function, and spirit. It also features a step-by-step potentiometer which eliminates low volume imbalance problems If the power amp used 2 O/P tubes each channel for OTL operation (a pretty common OTL design), simply series up all the heaters of all 4 O/P tubes & it will need 50. The drivers are parallel 6SN7 triodes, one tube with the triodes in parallel for each phase for a lower output drive impedance. free. brient. 4-5x 6c19p=1x6c33cb. Single Ended 12B4A Integrated Amplifier (Part 1) Single Ended 12B4A Integrated Amplifier (Part 2) Headphone amp Attached schematic might help you achieve those goals This is probably the reason why we don't have many OTL tube amps. lot's of OTL amplifiers , Sakuma San articles Schematic only are very " Spud " style with his R input and his dedicated psu. Tube amplifier transformer output seEl86 800 ohm com 6s33s 6c33c More Single-Ended OTL Designs Last time, we saw several possible 6C33C-based OTL power amplifiers, both hybrid and pure OTL, both single-ended and push-pull. This article covers the latter, a very nicely made PCB which features an octal (8-pin) tube OTL headphone amp circuit. The amplifier closely follows a Philips design from the early Here is a schematics of a 3W 6C33B-C SE OTL amplifier for midrange compression driver and tweeter, but the frequency range and power can be extended: http://vincent. The quasi OTL design used a solid-state power buffer to get more power output. My headphone's parameters: Max. Will appreciate any design whether PP or SE. For 6AS7-based Futterman OTL (for amp see schematic below) Large Regulated Power Supply; For Quad 6146-based PPP (for amp see schematic below) Small Regulated Bench Supply. Forums. Key points: - The design uses a novel non-complementary totem-pole output stage with local feedback to achieve good symmetry and cancel This OTL tube headphone amplifier is a more refined design of my previous amplifiers (see A Top-Level Headphone Amplifier). xDuoo is a popular brand in the audiophile world, with a wide range of amplifiers and source gear for headphones and IEM users. 5 ohm. At the heart of the matter, I failed to consider the use of stacked secondaries in I just had carpal-tunnel surgery, so I'm short a hand for a few weeks. PCL86 â in one tube is triode used in driver stage and pentode in power stage. What is the sound of an OTL tube amp like? OTLs have a distinctive sound. In the world of audio, tubes are often docked for poor bandwidth and high distortion by the advocates of This Class A tube headphone amp project, which the author created for Vintage Audio, includes a 6SL7GT for the input stage and a 6AS7G for the driver, and is able to drive headphones with impedance at or above 64Ω. I did the Preamp Output ground (remove) mod Greetings Friends. Does anyone A quick explanation of the amp channel schematics: One half of V1 is configured as a standard triode voltage-amplifier stage, Resistors R2 (42k) and R3 (750 Ohms) set the operating conditions, and resistors R1 (1M) and the 100 Ohm grid stopper resistor act as the input, the input signal appears on pin 1 of V1 amplified and inverted, pin 1 of V1 is directly coupled to Show your OTL Tube Amplifiers ! :) OK : OTL stands for Output Transformer Less :D At the start, a small circuit imagined by PHILIPS in Europe in the early 50s. Tube Lovers Anonymous 6C33C-B OTL Amplifier - Background and OTL Circuits-----INTRODUCTION The purpose of this paper is to explain the selection process and trade-offs involved in choosing the circlotron as the optimal topology for a high-power OTL amplifier. ). Sharing time. Practical methods are former-less (OTL) tube amplifier. 05W (50mW) Max. Can anyone sent me a detail schematic with component value ? Top . Tube Power Amplifiers: Single Ended Hybrid 12B4 The two sections of the 6336 or 6528 are run in parallel, each tube biases at 275mA with the components cold. The schematic. 0) Tube Gurus: What's a good and simple OTL using 6080's or 6AS7's that would be suitable for a first timer? A 6AS7 or 6080 pp is a superb sounding amp. It refers to a tube amplifier usually, one without an output transformer. Page 1 of 2 [ 16 posts ] Go to page 1, 2 Next Previous topic | Next topic : Author Message; and you should get excellent performance. The input stage is described in detail on the OTL Amplifier Input Phase Splitter Schematic web page. The only problem is that very few ready-made unity-gain power buffers are available. A few mods have been suggested for the 336se. Regular tube amplifiers have very high voltages in them and by contrast most loudspeakers are low voltage. Words alone cannot reveal the OTL tube amp experience. For more informations, visit his site. 2. 3Vpp) Max Today I finished building my 6082 Transformerless amplifier. Thanks. The article provides a full description of design fundamentals and some useful guidance on the construction process. 47 caps in the upfront feedback networks are actually 0. A SET (or Single-Ended) tube amplifier is the next-best thing to an OTL amp, but it still cannot match up to the quality of sound that the OTL amplifier can offer. Given the 72-ohm load, the solid-state power amplifier was voltage limited; given the 8-ohm load, the OTL amplifier, current limited. You cannot completely trust the schematic on the web. Yes, this is a well-known schematic - derived from Mr Futterman's original patent too, if you imagine by the thought the X cross of the driver's outputs on the 6080 upper and lower, which is not shown below though : View attachment 2876625 And that's an important point to ensure the perfect operation of the amp. Actually, there are several errors in the schematic. Figure 1. This old-school engineering method paired with modern The Tube amp Library of information Click the link above for Tube amp info, Schematics, Board building information, Projects, Mods, Transformer diagrams, Photo's, Sound clips. Please visit my Tube Amplifier Forum Here's the place you can go to ask tube amplifier questions. Member. Instead of 6C19 I used 4x PL504 per channel with a single 12AT7 section as input stage. Discover how it enhances your music with detailed, rich sound and learn about its professional-grade components and durable aluminum alloy shell. The amplitude of the harmonics that produce the tube distortion in these old schematics (the "tube sound") is fairly low compared to the fundamental. Then came Julius Futterman in USA, then ETONE, LUXMAN, OTL = Output Trasformer Less Tube Amplifiers My consideration on problems of each design: Ciclotron balanced design problems (type 1): Schematic by P. Forum Donor. Keep in mind that were many small variations between models 1. Let us know what you decide. So the current through the upper section would be (405 - 355) / (15K + 4K7) = 2. Others might prefer higher current drivers but either way the 6AS7 New to this forum. The circuit is a classic and in the next Introducing xDuoo's TA-66 high performance OTL Tube amp/preamp that brings a classical tube amp spirit to your rig. Much better performance, as the distortion at full output (64W) fell below 0. Picture of my old OTL amp. Before this one I built an OTL with 6 penthode connected pl519 s which needed a large amount of nfb to make the sound bearable. Tube Amplifier Schematics (OTL,,,B,VT4C) WW. output transformerless tube audio power amplifier. Amplifier & Power Supply. It has a grounded cathode input stage with an idling of about 3mA. voltage: 1. Logged transformers (if I remember correctly) to complete it. This time though, weâre making one critical change â weâre el It is called "6as7 mini OTL" on the website, and the author has links to the schematics of the power section and on the amp. Our designs emphasize simple, trouble free operation. So I now intend to build a basic Circlotron type OTL power amp using 2 6336As per channel. I also wanted to use an unconventional design. Maybe one could say it captures the best of both worlds. Something like that would be a realistic build and wouldn't heat your whole house. The simplest way to reduce the feedback to 11dB is to omit the cou-Presenting a new output-transformerless circuit with direct coupling to the loudspeaker. 12/17/2001: Ying Mingyao wrote: I have finished my first headphone amp according to the single-ended OTL amplifier from Aren van Waarde. You might call it the Ferrari of tube ampsâGraaf is located near Ferrari Central in Modena, Italy. Any ideas, a simple schematics maybe ? I'm not an electrician but I can solder and had some little projects already, all with success. I would not use this circuit to drive anything more expensive than an NSB, ($0. looking for the top 6080 amp schematics. This Before we get into specifics on output transformer less (OTL) circuits, first let us consider what the output tube must do that is different from amplifiers with output transformers. I have a large collection of these tubes, thought I'd do my own version of the circuit, it's now something I build on a select basis for Head-Fi friends, they seem to like it. 047 caps in the actual amps, or at least in the 4 or 5 I have seen and owned. Here is the actual schematic of Futterman's OTL amplifier. I did not think this was possible but in a "Boy's First Book of Electronics" a schematic was provided for a one stage amplifier with only one 1h4 power tube and no driver tube or rectifier tube. I might try it since I have several NOS C3g in storage. Another Power Supply. of DownloadReport. 2007-03-01 7:36 pm #2 2007-03-01 7:36 pm M-60 OTL Revised Signal-Path Schematic Now that we've got a first-draft schematic for the M-60 power-supply posted for review, I'll start work on the complementary revised M-60 signal-path schematic that reflects the "hot-rod" M-60 configuration (deleted Class-A/AB circuitry, increased bias current for the input-stage, etc. Joined 2003. 6AS7 OTL; This document summarizes the design of a 25W OTL tube amplifier that can be built yourself. This design uses more current because the HLMP-6000 led is the most linear when driven at 10mA, 9/24/98: Added Rin to both amplifier schematics (figures 3a and 3b) and removed 6VDC output from slow-start power supply schematic (figure 7). We also have a world class tube line level preamps and tube phono preamp. 2008-12-01 8:10 pm Well, I'd say that if you are in search of some efficiency for moderate investmentIMHO, rather forget the OTL amps circuits ! I mean those without any output transformers, otherwise the main benefit of the elimination of the said transformer is lost. Thanks, Klimon. Building, troubleshooting and testing of these amplifiers should only be so I did some searching for OTL headphone amp schematics and found a really interesting build article on the Headwize Memorial website by a guy named Bruce Bender, the article was based on another Weâre thrilled to introduce the xDuoo TA-66, an OTL headphone tube amp that merges classic engineering with the convenience of modern components. IMHO one solution and substitute for full tube OTL can be the Hybrid AB-class OTL amp , where input voltage gain stage and driver stage remains tubes, but output power devices are modern RF Lateral Mosfets , for example NXP- MRF101 , intented for linear amplification with relative low internal capacitances , it is one very ruged and easy On the Tung Sol data sheet below for 6BM8 they present an application note for using 6BM8 as a one tube two stage OTL AF amp. Hi all! This is one of my last valve project. 1. Tubes are yugoslavian Ei PCL86 NOS â new old stock â produced with Philips technology. 3A= 4. But after doing some initial research decided I didn't like the inherently unsymetrical nature of the futterman type OTL circuit. Hopefully someone else can point you to a schematic of an amp that meets your requirements, and works. Since Svetlana 6BM8 is in current production and I've been trying to decide on a simple one tube OTL amp project, this might be good. Learn how to design OTL amplifiers. In fact, the 6EM7 amp schematic posted here 6EM& v2 Schematic would be a great candidate (with 16Ω outputs of course). One of my (many) OTL amplifiers. The schematic shows one channel of a stereo amplifier, and the power supply is sufficient for both channels. I have seen schematics of two different versions of this, one in an old 1962 radio book that I have and another on the web which was published in the February 1990 issue of a magazine which I've never heard of call "Glass Audio". However looking at the curves of the 6C33, some of the percieved sound quality will come from driving the tubes really hard. We have covered quite a few of their desktop and portable amplifier products, such as the MT-604, the XA-10, and the cheaper TA-10 amplifier. Building, troubleshooting and testing of these amplifiers should only be If I liked the original OTL schematic, I would simply get a couple of 12AU7 or 6SN7 tubes per channel and build it. For the 4 main channels I would use a P-P tube amp of about 50 WPC. - eradicate the little remaining 100Hz ripple heard in the speaker. WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES. It is on my future project list. 69 WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES. 2 Amps for the array of 15. The bottle head crack is an OTL tube amp. Rather than use a PCB, this amp uses point-to-point wiring, a traditional technique that connects every component together with copper wiring. Latest is an ECC99 White cathode follower output with a 12AT7 as input I was planning to build a Lux MQ-36 6336A OTL amp clone. For example, in the 16W Circlotron OTL, the 2A of idle current against 100V of B+ voltage equals 200W of dissipation at idle, resulting in an 6C33C PP & OTL 1. Projects. Most of the topics have proven, although no doubt enthralling and informative, OTL headphone tube amplifier for low impedance headphones. M-60 OTL Signal-Path Schematic Schematic (v1. But 2 ohm or 1 ohm speakers are out. There is quite a lot of OTL amps schematics available nowadays, but I think the best ones are based on 6C33C tubes in output stage. 6AS7 OTL; Here is a schematics of a 3W 6C33B-C SE OTL amplifier for midrange compression driver and tweeter, but the frequency range and power can be extended Search. Our new DIY Speaker design is an excellent match and will provide extremely loud sound levels. The amp is easy to build and it has a true tube sound and very excellent performance. Amplifier. Thanks for correction ! It is very much worth to build the OTL amp if you feel the time has come. bias reisstors for one tube not ten in the output stage. The 3x-dual-triode topology seems an ideal I am not very good at some of the nuances that others apparently can hear, but my feeling is that a tube OTL is somewhere in between a good solid state amp. It can roughly be compared to Bottlehead Crack, the latter being better built and pricier. 5 mA. By the way, all the commercial OTL amps cost a bundle e. makes as much sense as I, using 6922 and Transistor in supertriode format and building the OTL capable of driving 8 ohms. xDuoo has an offering for pretty much everyoneâs desktop headphone and speaker Miltra OTL-PCL86 is a tube headphone amplifier designed for music lovers who appreciate full sound, high durability and quality. Most of the posts and articles I've found seem to focus on optimizing the amp to drive low impedance headphones, but I have a pair of HD 600 so I want to build an OTL amp to drive Hi-Z cans. First one had a SS output with tube input, second was a SRPP+ build. -Category Forums. This is not an amplifier which should be placed where small children or curious pets roam. The lights would get very dim when turned on. 7. Each channel now holds an extra tube, a 5687 in this case, but any 12-volt-heater tube would work (although probably not as well); for example the 12AU7, 6AS7GA OTL. The company was created by the âPresident In this episode, we revisit the low voltage audio amplifier that we built many, many moons ago. The issues involved in making this selection include circuit simplicity, balanced Both the 6XX and DT880 benefit from being driven by an OTL tube amp, and the Crack provides a crystal-clear example of this. Class A amplifier. The output is taken from the plate (pin 6) and direct coupled to the 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. Building, troubleshooting and testing of these amplifiers should only be performed by someone who is thoroughly familiar with the safety precautions around high voltages. An OTL headphone amp with a 6N1P in ground cathode for input stage and a 6N6P in SRPP for the output stage. My wish is to build a new amplifier - also single ended with a bit more power. If you find any mistakes are changes, contact me (see contact info on home page). sounded really nice. Hope A DC-Coupled Tube Amplifier With Futterman Output Stage for Dynamic Headphones - The A Low-Voltage Class-A Tube Headphone Amplifier - This OTL design features. 200 watts of tube amp power could be run a lot closer to clipping without sounding bad and be as loud as 1000 watts of SS power set to avoid clipping on loud peaks. So add a dirt-chip sand diode & a low-ohm start-up current surge suppressing resistor upstream of the heaters string (4x6C33C-B) & then connect direct up Figure 1 Hybrid tube/FET audio amp with active feedback Since the op-amp output is at or near common potential, the vacuum tube pentode input stage is cathode-biased via R5 in the normal fashion. MarcelvdG. Transformer T2 supplies the voltages required for the vacuum tube For "OTL Tube Amp" I would probably just do a Futterman style Amp using a sensible output tube that can drive 600 Ohm (maybe a few 6N30 in Parallel) and add P-Channel Mosfets in a compound feedback pair to drive low impedance loads. I use 6C33C in my OTL amp also which I think is a good choice, I have only heard the 6C33C in transformer coupled push This is the project page for our EL34 6SQ7 tube amplifier build. Okay, I just ran some SPICE simulation on this OTL amplifier with a 12AT7 input tube. I did see at least one OTL amp referenced on his site. tubetvr. tombethe Post subject: Re: schematic of 6C33C Another day, another headphone amp :) One of my life's pleasures is digging around on eBay for exciting finds, whether it be obscure vintage tube equipment or interesting/useful PCBs. SCHEMATICS . I use low current drive in my amp and love the sound it makes. For this project, I wanted to build a vacuum-tube-based amplifier for my office computer. Rail voltages are +120V for the output tubes, +300V for the input stage and +-12V for bias and input stage heater. Alternate schematic (current-sourced grounded-cathode amp, for "normal" headphones) (38k PDF file) Parts list (text file) Link to transformer data sheet (Sowter 8665) Link to In audio, the acronym OTL has been around since the 1950s. Documents.
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