Designing power supplies for tube amplifiers pdf


 

Designing Power Supplies for Tube Amplifier. medical-site.info text/medical-site.info Tube Amplifier Designs Rarely Change. . Tubes, Transformers, Power Supply Voltage. .. Designing a Negative Supply For Grid Bias. Essential Book: Designing Power Supplies for Tube Amplifiers On a whim, I bought Merlin Blencowe's book. I have to admit that I had low.

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Designing Power Supplies For Tube Amplifiers Pdf

medical-site.info: Designing Power Supplies for Tube Amplifiers If you're keen to see what's in store before you download, PDF previews are available on the author's. Power Supply Design for Vacuum Tube Amplifiers using Rectifier The design of basic tube power supplies is actually very straight This article is also available in PDF format - Basic Tube Power Supplies - PDF (MB). Choose one of these tried 'n' true circuits to meet your power supply needs. Article prepared for www. . ized circuits ECC83 (12AX7) is used for control DC amplifiers or reference isolation and sensing. . The design of the power transformer.

June 4, It was a cold January Saturday night in Chicago and we had big plans. Time to celebrate. Skip the glass, one pitcher each and keep them coming. Conversation evolved into bloviation on what our cover art would look like, certainly it would be a photo of our battery powered tube mic pre-amp recently created in my basement lab. Our rate of Goose Island and Guinness consumption would put us at three-sheets to the wind by Must focus. Make it work.

The Elliott Sound Practices web site offers wonderful heatsinking explication, guidelines, and design practices. In spite of the word "tube" in the book's title, I instantly assumed that Mr.

Blencowe was a Brit, not just because his first name is Merlin. Under the dust jacket, the book's spine and its inner title page reveal the book's true title, Designing Power Supplies for Valve Amplifiers. Moreover, Mr. Blencowe writes like a Brit, abundantly displaying good manners, never lapsing into excessive informality deferential, glad to be of use, politic, cautious, and meticulous Do not get me wrong here, as I greatly prefer such a style over the "Hey Dude, pass me the roach, I mean alligator clip" style of many guitar amplifier books.

Still, for this American, Mr. Blencowe's over reliance on a somewhat passive and circumlocutory exposition wearies.

For example, he begins a section titled "Relative output voltages of rectifier circuits" thus:. There are two or three power-supply topologies which are seen again and again in valve amps, and are regarded as almost standard, being more-or-less copied from the popular, early amps.

However, it is worth noting that these designs are not compulsory; there are many ways to arrange the same transformer and rectifier, depending on the output voltage we need. After the first hundred pages, I felt like slapping him on the back and telling him, "Just spit it out man" and I am a rabid anglophile. As I read the above paragraph, my mind translated it into American thus:.

Power Supply Design for Vacuum Tube Amplifiers

Most modern valve amplifiers hold a power supply identical to those found in old valve amplifiers, which seems to imply that these old topologies are standards not to be altered—yet these hoary topologies are neither compulsory nor necessarily best. Depending on our design goals, the same transformer and rectifiers allow many different arrangements, indeed, often better arrangements. Perhaps, I am making a Maugham out of a molehill, you know, Somerset Maugham as few readers are likely to read this book in a single sitting as I did and his prose is still far more spritely and readable than any modern electronics textbook I have read—and I have read plenty.

In general, electronics textbooks written before are lucidly and gracefully composed. The urge to make some snide comment on the modern educational system was almost impossible to resist, such as: How could so much have been achieved without a Department of Education, establish in ?

Fortunately, I held firm In conclusion, in spite of a few minor, very minor criticisms, I highly recommend this book, for beginners and masters alike. Beginners should read the first five chapters over and over again, as they cover essential material, such as transformer selection, rectification, and filtering; particularly, the chapter on LC smoothing filters, as most tube fans know nothing about the problem of LC resonance.

Power Supply Design for Vacuum Tube Amplifiers

Advanced practitioners will find much to like in these and in the following five chapters. Many pure tube-based and solid-state-based and hybrid solutions are illustrated; there is even a quite Janus-like shunt regulator that utilizes both feedforward and feedback to produce clean, steady DC voltage, page ; And the last chapter is a must read, as it covers the problem of too little or too much wall voltage and some possible solutions. Today, however, it is not enough that a book be well written, illustrated, researched, and organized, as it must pass the new test, the web test: If I can find all the same material on the web for free, do I really need to download this book?

In the case of, Designing Power Supplies for Valve Amplifiers, the answer is yes, you need the book, as you cannot find it all on the web; no doubt, many portions can be found, but not everything—and certainly not in such a well packaged format.

Additionally, you can put your trust in Mr. Blencowe's efforts. Can you say that about all that you find in a Google search?

Vacuum Tube Power Supply Design

Starting with the compulsory throat clearing, let's look at two old designs. The first uses the famous LM positive, adjustable voltage regulator and a high-voltage triode. I remember seeing this schematic in an old National Semiconductor data sheet over 30 years ago.

The low-voltage regulator establishes and maintains the fixed output voltage, while the high-voltage triode shields the solid-state device from lethal voltages. The LM strives to maintain a constant 1. As tubes grew ever less popular in sober electronics, this circuit was expunged from later data sheets. High Voltage Adjustable Power Supplies. The single triode had been replaced by two high-voltage transistors and some extra support circuitry. The design functioning remained the same: Well, all of this is old hat.

What intrigued me was this question, Is it possible to make a high voltage regulator based on an LM? No, not a high-voltage negative regulator, which would be merely a mirror image of the above circuit, with PNP transistors replacing NPN types, my goal was a positive high-voltage regulator. No one asked me this question; I was just giving myself a brain teaser. My first thoughts were that it would certainly be possible to create a shunt regulator, such as the following.

Where to start? This high-voltage shunt regulator looks far more complex than it really is. The LM is in control, measuring the output voltage and applying corrections as needed. In other words, they are not safety devices the way the unmarked diode is 1N in the schematic. The zener both establishes a fixed reference voltage and a current path in parallel with the LM The LM will use all its considerable negative feedback to keep a steady 1.

In other words, the LM is constantly evaluating the voltage it sees at its output and adjustment pins, as it strives to maintain a fixed voltage difference between the two. The LM really doesn't know that it is the heart of an elaborate high-voltage positive regulator; all it knows is what is happening at its output and adjustment pins.

Thus, we must overlay two critical signal sources on top of these two pins: Ground isn't a signal source. Actually, in a voltage regulator, it is THE signal source, as a voltage regulator can be viewed as being a powerful unity-gain amplifier, with a huge fixed DC offset and whose signal source is ground.

Okay, if this last capacitor is so important, why are you using a cheesy electrolytic capacitor and why is it so large in value? But the capacitor also terminates into the ohm resistor, which is effectively grounded at its other end. Of course, this would also greatly reduce the current flow through both the zener and the LM negative voltage regulator. Not good. But if we place a power resistor s in parallel with the resistor string, the LM and zener can still get the current they require.

National Semiconductor makes or used to make a high-voltage version of the LM, which can withstand 47V between its input and output pins. In addition, our shunting triode might require even greater potential cathode swings.

This is the baby-step circuit before we move on the actual circuit; nonetheless, it might prove adequate for many preamp and line-stage amplifier applications. Although the negative bias voltage tap is usually only found on big power transformers that were intended for use in tube power amplifiers. Now we arrive. Can a positive, high-voltage, series, voltage regulator be made out of an LM?

It can. The following schematic is stripped down, so as to leave its operation on display without the clutter of the safety and performance-enhancing components. For example, although he praises silicon thermal pads, so much tidier, he says nothing about the up to 1.

Keep Those Filaments Lit, Design Your Own Vacuum Tube Audio Equipment

Instead, I was surprised to see him give 0. The Elliott Sound Practices web site offers wonderful heatsinking explication, guidelines, and design practices. In spite of the word "tube" in the book's title, I instantly assumed that Mr. Blencowe was a Brit, not just because his first name is Merlin. Under the dust jacket, the book's spine and its inner title page reveal the book's true title, Designing Power Supplies for Valve Amplifiers. Moreover, Mr. Blencowe writes like a Brit, abundantly displaying good manners, never lapsing into excessive informality deferential, glad to be of use, politic, cautious, and meticulous Do not get me wrong here, as I greatly prefer such a style over the "Hey Dude, pass me the roach, I mean alligator clip" style of many guitar amplifier books.

Still, for this American, Mr. Blencowe's over reliance on a somewhat passive and circumlocutory exposition wearies. For example, he begins a section titled "Relative output voltages of rectifier circuits" thus: "Most of the power supplies found in audio amplifiers follow conventional though not necessarily best design practices, and common arrangements or topologies can usually be recognised when looking at various amp designs. There are two or three power-supply topologies which are seen again and again in valve amps, and are regarded as almost standard, being more-or-less copied from the popular, early amps.

However, it is worth noting that these designs are not compulsory; there are many ways to arrange the same transformer and rectifier, depending on the output voltage we need. As I read the above paragraph, my mind translated it into American thus: Most modern valve amplifiers hold a power supply identical to those found in old valve amplifiers, which seems to imply that these old topologies are standards not to be altered—yet these hoary topologies are neither compulsory nor necessarily best.

Depending on our design goals, the same transformer and rectifiers allow many different arrangements, indeed, often better arrangements. Perhaps, I am making a Maugham out of a molehill, you know, Somerset Maugham as few readers are likely to read this book in a single sitting as I did and his prose is still far more spritely and readable than any modern electronics textbook I have read—and I have read plenty. In general, electronics textbooks written before are lucidly and gracefully composed.

The urge to make some snide comment on the modern educational system was almost impossible to resist, such as: How could so much have been achieved without a Department of Education, establish in ?

Fortunately, I held firm In conclusion, in spite of a few minor, very minor criticisms, I highly recommend this book, for beginners and masters alike. Beginners should read the first five chapters over and over again, as they cover essential material, such as transformer selection, rectification, and filtering; particularly, the chapter on LC smoothing filters, as most tube fans know nothing about the problem of LC resonance.

Advanced practitioners will find much to like in these and in the following five chapters. Many pure tube-based and solid-state-based and hybrid solutions are illustrated; there is even a quite Janus-like shunt regulator that utilizes both feedforward and feedback to produce clean, steady DC voltage, page ; And the last chapter is a must read, as it covers the problem of too little or too much wall voltage and some possible solutions.

Today, however, it is not enough that a book be well written, illustrated, researched, and organized, as it must pass the new test, the web test: If I can find all the same material on the web for free, do I really need to download this book?

In the case of, Designing Power Supplies for Valve Amplifiers, the answer is yes, you need the book, as you cannot find it all on the web; no doubt, many portions can be found, but not everything—and certainly not in such a well packaged format. Additionally, you can put your trust in Mr. Blencowe's efforts. Can you say that about all that you find in a Google search? Starting with the compulsory throat clearing, let's look at two old designs.

The first uses the famous LM positive, adjustable voltage regulator and a high-voltage triode.

I remember seeing this schematic in an old National Semiconductor data sheet over 30 years ago. The low-voltage regulator establishes and maintains the fixed output voltage, while the high-voltage triode shields the solid-state device from lethal voltages. The LM strives to maintain a constant 1. As tubes grew ever less popular in sober electronics, this circuit was expunged from later data sheets.

The single triode had been replaced by two high-voltage transistors and some extra support circuitry. Well, all of this is old hat. What intrigued me was this question, Is it possible to make a high voltage regulator based on an LM?

No, not a high-voltage negative regulator, which would be merely a mirror image of the above circuit, with PNP transistors replacing NPN types, my goal was a positive high-voltage regulator. No one asked me this question; I was just giving myself a brain teaser. My first thoughts were that it would certainly be possible to create a shunt regulator, such as the following.

Where to start? This high-voltage shunt regulator looks far more complex than it really is. The LM is in control, measuring the output voltage and applying corrections as needed. In other words, they are not safety devices the way the unmarked diode is 1N in the schematic. The zener both establishes a fixed reference voltage and a current path in parallel with the LM The LM will use all its considerable negative feedback to keep a steady 1. In other words, the LM is constantly evaluating the voltage it sees at its output and adjustment pins, as it strives to maintain a fixed voltage difference between the two.

The LM really doesn't know that it is the heart of an elaborate high-voltage positive regulator; all it knows is what is happening at its output and adjustment pins. Ground isn't a signal source.

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