Output transformerless tube amp schematic software

Otl, output trasformer less tube amplifier designed by. Its a simple enough question, but the answer is a little complex. Tube amp schematics index page there are over 3500 tube amp schematics and other types of schematics in the el34world schematic library. A transformerless amplifer is described using four tubes connected in a bridge circuit and so driven that each tube delivers equal power to a common load. How do you get a 150ohm mic signal to the 15k or so ohms a tube would like to have and then after the signal has been amplified back down to 600ohms. The output that results when the peak value of the input is changed to 2 v is shown in figure 1626c. I told him i could build something unique for practically nothing. Keep those filaments lit, design your own vacuum tube. Like vacuum tubes, transformers are vital to the sound and performance of your amplifier. New york audio laboratories futterman otl1 power amplifier. They are usually used for relatively small amplifiers, e. The power output depends a lot on headphone impedance. Even an entrylevel radio from the 20s or 30s might have as much as 500v dc with 50100 ma of current available. Fortunately since i go to local headphone meets ive been able to hear very good tube amps of various designs.

The 2a3 tube amplifier a tribute to simplicity and warm. Vacuum tube output transformer measurements determining turns. Berning technology tube amplifiers for highend audio by. I made this connection off of the a side of the main output cap. Bsch3v is an open source circuit design software for windows. Nov 19, 2015 figure 1626a shows the spice circuit and input data file for the case where the input signal has peak value 30 v. Jan 17, 2014 this is coming from the guitar amp world, as im a player and collector of tube guitar amps.

Mar 17, 2018 this otl amp features a singleended class a input stage and a paralleledtube cathode follower output stage with 33 ohms output impedance. Higher output z results in less power to the transducer. You have the flexibility to choose the software which you need. All the schematics youll find below are quite large, enough to keep the value of the components readable. You can get a circuit board from them or you can build it point to point. Conventional vacuum tube amplifier designs rely upon an output transformer to couple the amplifier s output stage to the loudspeaker.

If you have experience with electric guitars that a tube driven and listen to otl and ot amps. On the schematic and choose the option save image as and print it with a common bitmap program. Select a component, and click on ok to place it on the circuit board. Because of this, the cost of the output transformer often accounts for a very big part of the total cost of a tube amplifier. Keep those filaments lit, design your own vacuum tube audio. Push pull vs otl vs set tube amps super best audio friends. 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. Figure 1626a shows the spice circuit and input data file for the case where the input signal has peak value 30 v. Multiple power supplies these days should be no problem, its so easy to do a hv supply these days with all the cool suitable parts available. Sesingleended, pppushpull, otloutput transformer less. Outputtransformerless tube guitar amplifier a c i d b o u r b o n.

Why and how to replace your amplifiers output transformer. If you see a problem with any of the schematics, please email me so i. As written, output impedance of nutube is very high several hundreds kohms and very far from driving headphone and speaker. Nowadays the tube amplifier, in whatever configuration, is considered to be a musical instrument par excellence. High current transformerless power supply circuit homemade. The basic design has been around for a long time 50 years or so. 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. Circuit is simple, voltage dropping capacitor of 225j is connected in series with phase line of ac, this is a nonpolarised capacitors so it can be connected from any side. While this article is intended primarily for the homebrew builder, it will also be useful background for the kit builder. Circlotron valve amplifier is a type of power amplifier utilizing symmetrical cathodecoupled bridge layout of the output stage. Feb 23, 2009 i know there are some tube amplifiers for hifi that are output transformerless otl that use for example capacitor coupling instead of transformer though i do not know of a guitar amp that does this but then again i havent looked for one either. We will now evaluate the software which runs on different operating platforms. Cfb helps lower the distortion produced in the tube, it cant do anything for the magnetic saturation effects seen at 44 hz above 6 watts.

Larger transformers are typically supplied with an epoxy potted center with a hole for mounting. Im quite confused regarding the effect of output transformerless and transformer coupled tube amps on the sound quality. The veritable 12ax7 was the work horse dual triode pre amp mixerdriver of choice in the 195060s. Again, not sure why, make it sound less like a tube amp. Because ultimately i wanted to build a guitar amplifier of course i needed. The tube amp library of information click the link above for tube amp info, schematics, board building information, projects, mods, transformer diagrams, photos, sound clips. That sounds like a lot but remember the tube heaters will be powered by this transformer too. The ac equivalent circuit of the amplifier may be represented by a generator of voltage 2esymbol in series with the plate resistance rp of one tube. Please visit my tube amplifier forum heres the place you can go to ask tube amplifier questions. The output stage is conventional with two exceptions. To my opinion he was the last person adding a new amplifier circuit topology to. Otl amplifier celebrating twenty years of michel vanden. Output transformerless vs transformer coupled output tube.

The circuit has significant output impedance something like 500 ohms which some headphones dont mind, some do. Yet another way is to design special circuits such that there is no longer any need for either output. Click on the component icon to access the list of components. The output transformer in a singleended tube amplifier is the device which matches the high output impedance of the tube to the low input impedance of the speaker load 4, 8 or 16 ohm. Thats it for the signal path, now lets examine the amps power supply shown at the bottom of the schematic. Tube amp schematics, tube amp information, tube amp projects. Amplifiers without the output transformer therefore produce cleaner, less distorted sound. The following guidelines should be taken into account. I recall one esoteric tube amp a few decades ago that used a ton of output tubes in parallel to eliminate the need for an output transformer. The amps do use transformers like any other high voltage amp. Afbeeldingsresultaat voor krystalka s jednou elektronkou pushpull pp el84 6bq5 or 6v6 6aq5 tube amp schematic with dynaco a410 transformers see more.

Pushpull the basic principle behind this amp is pretty cool and worth taking a look at. Vacuum tube audio amplifier discrete semiconductor circuits. Some excellent sounding tube amplifiers have output transformers that are painstakingly. Regular tube amplifiers have very high voltages in them and by contrast most loudspeakers are low voltage. To make an amplifier without a main power transformer widowmaker safe do the following. What are the best musical sounding capacitors to use or recap. The tenor audio journey began in early 2000 with the innovative output transformerless amplifier known as simply the tenor otl. Im just now getting into exploring the headphone amp world. Tube sound or valve sound is the characteristic sound associated with a vacuum tube amplifier valve amplifier in british english, a vacuum tube based audio amplifier. The other exception is the use of dc on the filament. The authors give a general discussion of this type of amplifier using transformers solely as matching devices. A first approach is simply to use normal circuits with the loudspeaker directly replacing the. A true single ended output transformerless valve tube test.

This page is about otl amps, strengths and weaknesses, and why not having an output transformer may ruin good music. A practical commercial outputtransformerless amplifier. There is a computer program that comes with this page to help you. The more tube amps i hear the more i realize that a full tube amp is probably what im after. Outputtransformerless tube guitar amplifier a c i d b. Powerdrive allows this, and the output tube likes the lower resistance. 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.

The problem with early applications was that it was. Mar 08, 2017 moreover i was hoping to find an output transformer in the carcass since they are the most expensive components to procure when building tube amplifiers but i could not find one. Single ended el84 tube amp information, guitar amp. Circuit of tube amplifier device the output transformer is an important part of the amplifier requiring a thorough parameter determination. Original circlotrons of 1950s used output transformers to couple relatively high output impedance of vacuum tubes to lowimpedance loudspeakers. Outputtransformerless tube guitar amplifier a c i d b o u. Years ago my brother and i were lamenting the state of hifi and how it now costs thousands of dollars for equipment. Ac wall power from the power cord flows through the onoff ac switch and on to the power transformer shown at bottom center which steps up the wall voltage to 325 volts rms root mean square average ac for the high voltage supply and steps it down to 6. Mc2152 70th anniversary 2channel vacuum tube amplifier. In this article we cover how to lay out and build the chassis for a vacuum tube guitar amplifier. The acoustat amp was not quite as good on current, construction or reliability.

Schematic is from the dynaco superfidelity output transformers catalog. Feedback can be applied to all amplifier types, where just like an op amp circuit some of the output signal is fed back to the input, allowing the amplifier. So i built the preamp stage of the ax84 high octane amp, so basically everything from the input jack up to the master volume poti. Unity coupled circuit output transformers 8 kt88, 4 12ax7a and 4 12at7 vacuum tubes. No practical details of a strict transformerless amplifier are given. Mcintosh amplifiers for home audio and home theater. Most experts state that dhts sound better with ac on the filaments. Aug 19, 2007 years ago my brother and i were lamenting the state of hifi and how it now costs thousands of dollars for equipment. This vastly improves the way the otl tubes operate.

Output transformers are a component that colors the sound. Schematic of a class ab tube power amplifier with negative feedback. The two output trannys are rotated 90deg to the power mains tranny to avoid picking up induced hum from the mains tranny external magnetic field. This amp is called a 6v6 pushpull amp, the 6v6 being the tube model, but whats this pushpull business. In both cases the signal from the lower output valve is fed to the grid of the. Its a pretty staight forward design but requires an input and output transformer.

The output transformerless otl amplifier was introduced and manufactured in very limited numbers for highend music lovers, although this new technique, like many other excellent ideas, did not become a standard. Transcendent sound produces vacuum tube audio amplifier kits that utilize otl output transformerless technology. Only a few hiend valve amps had output trannys that were made with the best quality materials. Conventional vacuum tube amplifier designs rely upon an output transformer to couple the amplifiers output stage to the loudspeaker. Vacuum tubes have excellent bandwidth and low distorsion without global feedback and resistance coupled tube amplifiers as used in pre amps often dont use any feedback at all, as an example the distorsion of a resistance coupled 12ax7 with 220 kohm anode resistance and 400v plate voltage is only 0. I did a bit of research on the radio philips jupiter 463 and the speakers online and i found out that there were some radio receivers that in fact did not possess. The so called totem pole circuit, power amp stage for an otl amplifier. Amp diy adventures in amplification gear diy amps howtos. Very nice, classic 3 tube, mono, class ab audio amp. Jan 17, 2014 im quite confused regarding the effect of output transformerless and transformer coupled tube amps on the sound quality. The result is an unbelievable clarity and realism that no other configuration can achieve. We call our technology zotl for zerohysteresis output. Output amplifier consists of a 6p1p output tube and output transformer fig.

I discuss why why you need so many tubes such as 6as7, 6336. How to layout and build a guitar amplifier chassis. For this project, i chose a matched pair of sovteks 2a3 power tubes and a matched pair of electroharmonix 12ax7 see photo 2. The library lets you choose from logic, discrete, digital, consw, and analog components. The acronym otl refers to a tube amplifier that is output transformerless. For this three tube 1430 amp i would use a triode magnetics n53mg rated at 85 watts and 740 milliamps. Tube amplifiers, schematics, parts, triode amplifiers.

The output of this opamp is backfed into the secondary of an audio output. To design an output transformer, it is necessary to determine the output power according to the tubess characteristics, most notably the input and output. The output transformer is the heart of a valve amplifier. Transformerless pushpull amplifiers electronics assignment. Output transformerless vs transformer coupled output tube amps. The only significant difference is the hybrid design. They use wide frequency transformers and put mosfets after the transformer to drive the speakers.

Sep 16, 2016 established in 1974, the david berning company manufactures vacuum tube audio amplifiers based on an unique impedance converter that replaces the traditional audio power output transformer and greatly extends and improves amplifier performance. I must mention that if the driver tubes are removed while the amplifier is in use, or the driver tube fails, the output tube can easily lose its bias voltage because there is no coupling capacitor in the signal path. There is also a huge library of effects and solid state schematics. Opt can take advantage of the high voltage low current nature of tube gear by converting it to more suitable voltages with more current. In general by suitably paralleling output valves a transformerless amplifier for. I just read one of the articles on output transformerless tube amp designs off that website. They might have some buffer circuit on the output, maybe coupling caps, but not output transformers. With a few essential tools and proper procedures, youll find that building a vacuum tube guitar.

It refers to a special case of differential circuits, where a whole signal is made up of the difference of two voltages, a negative and a positive technically speaking, only the output stage is push. But im still intimidated and unsure because i dont understand the things well enough. Otl tube amps are peculiar, uncommon designs that go to. Instead, otls use one of two primary methods for output stage coupling. Higher powers are obtainable with either very large power valves, or by using multiple valves in parallel, but beyond about 15w it is usual to use. You can use el84s if you like but i prefer the russian 6p15. Many hybrid amps have solid state preamps and power tube outputs. First off, lets examine what an output transformer is and why someone would inquire about replacing it. We call our technology zotl for zerohysteresis output transformerless. The majority of output trannys were the minimum size, made from the least expensive materials. They capture the best of both types along with the ability to develop incredible three.

Vintage unknown 7342x tube amp 357 vdc output transformer 60025015062. Jun 17, 2019 in the above scr based transformerless power supply circuit, the output is surge protected through the scr, but the bc546 is not protected. Loved the transformerless use of direct wall ac always a low level 60hz hum at full volume. The output impedance is pretty much constant and independent of load, but any tube changes will greatly affect it. The beveridge model 2 and 2sw amps put out 1,500 va like watts in this application. With the amp off and drained of residual power, i measured the resistance from pin 7 of each power tube to the white wire that comes off the output transformer. Now includes two highend versions based on the 6sn7 and the 3a5 directheated triode.

More than 80% of our transformers manufactured is for this market and bring over 70 years transformer manufacturing expertise to our product. A true single ended output transformerless valve tube test amplifier. 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. His zh230 amplifier has received absolute sound magazines editors choice award. Mar 20, 2018 i do recall seeing a schematic somewhere of a hi fi power amp that used a ton of 6v6s in parallel wired as cfs, and used as an output transformerless tube power amp. The free shipping option allows tubedepot to choose the most appropriate carrier and service. Basic schematic of the outputtransformerless power amplifier. This is where the vacuum tubes directly drive the loudspeaker with no intervening transformer. Established in 1974, the david berning company manufactures vacuum tube audio amplifiers based on an unique impedance converter that replaces the traditional audio power output transformer and greatly extends and improves amplifier performance. I am often asked how upgrading an amplifiers transformers will improve tone.

A true single ended output transformerless valve tube. Moreover, it is extremely difficult and therefore very expensive to make a good output transformer. Pushpull pp or tube amp schematic with dynaco transformers. Aes elibrary a new transformerless amplifier circuit. Unlike the normal transformercoupled, tube based power amplifiers that use common and readily available output tubes, such as the el34 and 6550, and simple input and driver circuits, otl power amplifiers use oddball tubes, such. Ive heard great examples of solid state, tube, and otl tube headphone amps and am having a hard time differentiating, because they are all so good. This time i just connect output transformer for vacuum tube to nutube as shown in the picture below. Output trannys contribute most of the distortion in a valve amp and have a limited bandwidth. The output stage is a selfinverting push pull sipp design after the compact hifi power amplifier by melvin leibowitz.

Zotl tube amplifiers are thoroughly modern in their design and approach. More obscure types of amplifiers include transformerless, where lots of tubes are. Circlotron architecture, easily scalable, was eventually adapted to operate without output. Widowmaker amps rob robinettes car and tube amp website. At first, the concept of tube sound did not exist, because practically all electronic amplification of audio signals was done with vacuum tubes and other comparable methods were not known or used. Because ultimately i wanted to build a guitar amplifier of course i needed a suitable preamplifier. We are also producing hightech otl output transformerless amplifiers and custom made to extreme high satisfaction guitar amplifiers, including tube guitar otl amplifiers. Audio amplifier software is need on operating systems like windows, linux, mac and also on mobiles which are ios and android base. Tube amplifiers for highend audio by the david berning. In order to ensure a complete protection for the entire circuit along with the bc546 driver stage, a separate low power triggering stage needs to be added to the b546 stage. I know there are some tube amplifiers for hifi that are output transformerless otl that use for example capacitor coupling instead of transformer though i do not know of a guitar amp that does this but then again i havent looked for one either. Beveridge and acoustat had the right idea in making a direct drive amplifier at high voltage and reasonable current. In both cases the signal from the lower output valve is fed to the grid of the upper so that the input signal varies the voltage across the output valves in opposite directions. There are hundreds of pages of tube amp information on my library page.