Hi Everyone
I have designed a simple two stage common emitter amp but would like to know where I might find some information about other design methods, or how to improve this design?
I can't seem to find any easily digestible information about other design routes for amplifiers. I have found lots of already designed pre-amps but not very decent info about how they work.
Does anyone know of any internet resources about designing amplifiers?
And I apologise if this is the millionth time this question has been asked.
Mash
I have designed a simple two stage common emitter amp but would like to know where I might find some information about other design methods, or how to improve this design?
I can't seem to find any easily digestible information about other design routes for amplifiers. I have found lots of already designed pre-amps but not very decent info about how they work.
Does anyone know of any internet resources about designing amplifiers?
And I apologise if this is the millionth time this question has been asked.
Mash
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Hi Mashly,
Good instructions you will find at Nelson Pass' DIY homepage passdiy or firstwatt.
He illustrates and explains each section of the amps.
In this forum are a lot of builders of his design and some are creating variations of it.
I like the paper from Nelson about "Super-symmetric amplification" and "Create a Class-A Amplifier"
The older Elektor papers are not bad and i think a lot of guys here like Douglas Self books.
Good instructions you will find at Nelson Pass' DIY homepage passdiy or firstwatt.
He illustrates and explains each section of the amps.
In this forum are a lot of builders of his design and some are creating variations of it.
I like the paper from Nelson about "Super-symmetric amplification" and "Create a Class-A Amplifier"
The older Elektor papers are not bad and i think a lot of guys here like Douglas Self books.
I can't think of any online resources tbh, not single ones anyway. John Linsley Hoods book "Valve and Transistor Amplifiers" is quite good and has a different approach to other more modern texts. Wow... how much 😱 See if your library will order a copy.
Valve and Transistor Audio Amplifiers: Amazon.co.uk: John Linsley Hood: Books
Your circuit could be improved. A combined two stage amp (using an NPN and PNP) would be worth exploring. Adding the caps across the emitter resistors to get lots of gain isn't ideal. A cap in series with a resistor is more controlled.... all depends what you want though.
Set your specification out first. Gain needed. Supply voltage. What load it has to drive and to what level etc.
Valve and Transistor Audio Amplifiers: Amazon.co.uk: John Linsley Hood: Books
Your circuit could be improved. A combined two stage amp (using an NPN and PNP) would be worth exploring. Adding the caps across the emitter resistors to get lots of gain isn't ideal. A cap in series with a resistor is more controlled.... all depends what you want though.
Set your specification out first. Gain needed. Supply voltage. What load it has to drive and to what level etc.
This study of a 2-transistor RIAA preamp is a good source of information :
Discrete design: 2-transistor RIAA preamp
Discrete design: 2-transistor RIAA preamp
JLH talks you through where to apply feedback both at AC and DC to get a really good performance out of 2 transistor and 3 transistor amplifiers.
D.Self also does a little on this, but I don't have his small signal book.
Doug Self's Small Signal Audio Design is indeed a goldmine for discussion of discrete gain stages and buffers, showing how to progress basic circuits from primitive to advanced. And, of course, the book illustrates how poorly they perform compared with opamps!
Looking at your circuit, you next step would probably be to learn about feedback biasing (aka "base bias") of transistors, rather than simple potential-divider biasing.
Looking at your circuit, you next step would probably be to learn about feedback biasing (aka "base bias") of transistors, rather than simple potential-divider biasing.
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Learning transistor design is unfortunately not cheap if time is not to be wasted trying to absorb detail and understand function from existing designs or internet publications. There are several useful internet resources, but I recommend buying books.
Ultimately you will take more aboard in whatever time you have available if you can afford some tuition.
Designs such as yours (cascaded common-emitter) are not common in hi-fi. They are frequently found in radios, often in narrowband incarnations, particularly portable QRP sets. Over the years, at baseband, more complex standard topologies offering improvements in performance in several respects, but most notably distortion vs. power output, such as the long-tailed pair, bias-spreader push-pull, diamond buffer and others have been developed. So numerous are these variations that it is too onerous a task to reinvent them, so it is necessary to become familiar with them by study or exposure.
Looking around the room I see all of Doug Self's books (although not every edition), Bob Cordell's Designing Audio Power Amplifiers, Wes Hayward and Doug DeMaw's Solid State Design for the Radio Amateur, Chris Bowick's RF Circuit Design and Morgan Jones' Valve Amplifiers. And of course Horowitz and Hill's The Art of Electronics.
These are of course just a fraction of a collection of books on maths, basic physics, foundations of electronics, communications, antennas and propagation, programming, DSP and a plethora of subjects which are required to approach competence as a general electronics engineer in this day and age.
Of course online you can find the Radiotron Designers Handbook in various editions.
In addition to BJTs there are of course both signal and power FETs, and, increasingly appearing, depletion mode FETs, very like tubes in their operation.
I recommend that anyone with a long-term interest in SS amplifier design should take the time to design and build a tube amp, to get an appreciation of considerations of higher voltage and lower current, how component dimensions and cost vary and how transformers and chokes and even caps are more commonplace in the signal path. It helps to break out of that BJT mindset, and also to see how the insights of yesteryear are not necessarily less profound than those of today.
Learn to use simulation. LTspice is free and very well supported, both here and elsewhere.
Ultimately you will take more aboard in whatever time you have available if you can afford some tuition.
Designs such as yours (cascaded common-emitter) are not common in hi-fi. They are frequently found in radios, often in narrowband incarnations, particularly portable QRP sets. Over the years, at baseband, more complex standard topologies offering improvements in performance in several respects, but most notably distortion vs. power output, such as the long-tailed pair, bias-spreader push-pull, diamond buffer and others have been developed. So numerous are these variations that it is too onerous a task to reinvent them, so it is necessary to become familiar with them by study or exposure.
Looking around the room I see all of Doug Self's books (although not every edition), Bob Cordell's Designing Audio Power Amplifiers, Wes Hayward and Doug DeMaw's Solid State Design for the Radio Amateur, Chris Bowick's RF Circuit Design and Morgan Jones' Valve Amplifiers. And of course Horowitz and Hill's The Art of Electronics.
These are of course just a fraction of a collection of books on maths, basic physics, foundations of electronics, communications, antennas and propagation, programming, DSP and a plethora of subjects which are required to approach competence as a general electronics engineer in this day and age.
Of course online you can find the Radiotron Designers Handbook in various editions.
In addition to BJTs there are of course both signal and power FETs, and, increasingly appearing, depletion mode FETs, very like tubes in their operation.
I recommend that anyone with a long-term interest in SS amplifier design should take the time to design and build a tube amp, to get an appreciation of considerations of higher voltage and lower current, how component dimensions and cost vary and how transformers and chokes and even caps are more commonplace in the signal path. It helps to break out of that BJT mindset, and also to see how the insights of yesteryear are not necessarily less profound than those of today.
Learn to use simulation. LTspice is free and very well supported, both here and elsewhere.
Well, a very good place to start is Horowitz & Hill, The Art Of Electronics. It is a book that can be read, unlike most text books. It covers the basics and quite a bit more.
Once you have that book, you will be able to delve farther into the field.
The big problem is that to do "design" properly, meaning you understand the inner workings sufficiently to master the subject is equivalent to a EE degree at a good university. Truthfully, one ought to have the math to be able to work through the engineering formula, since they show how it actually "works".
One can get pretty far with LTspice and MathCAD (or similar) and a pile of books, reading threads here on DiyAudio, and scouring the internet.
I'd take a look at the Discrete Opamp Open Design thread that is currently running here. While it is likely over your head, and some is over my head too (although that's mostly some of the finest details for me), just browsing through it is like sitting in a room with top engineers while they hash out the particulars of a new design. It will quickly give you the flavor of what this is all about.
Don't get turned off by the seemingly endless array of impossibly complex details, some of the participants ARE top engineers who actually do this work for a living - real pros. Just like we can't stay even with a pro athlete, how great would it be to participate anyhow! 😀
_-_-
Once you have that book, you will be able to delve farther into the field.
The big problem is that to do "design" properly, meaning you understand the inner workings sufficiently to master the subject is equivalent to a EE degree at a good university. Truthfully, one ought to have the math to be able to work through the engineering formula, since they show how it actually "works".
One can get pretty far with LTspice and MathCAD (or similar) and a pile of books, reading threads here on DiyAudio, and scouring the internet.
I'd take a look at the Discrete Opamp Open Design thread that is currently running here. While it is likely over your head, and some is over my head too (although that's mostly some of the finest details for me), just browsing through it is like sitting in a room with top engineers while they hash out the particulars of a new design. It will quickly give you the flavor of what this is all about.
Don't get turned off by the seemingly endless array of impossibly complex details, some of the participants ARE top engineers who actually do this work for a living - real pros. Just like we can't stay even with a pro athlete, how great would it be to participate anyhow! 😀
_-_-
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I have to say that this is the worst piece of advice I have seen offered for a long time. Valve (tube) design differs from SS design in just about every way. If you're designing with BJTs, then a "BJT mindset" is jolly useful.
well, that last post if from one of those "pros"... hee hee.
It's not bad advice actually, just somewhat dangerous for a newbie because of the high voltage. There's not really much difference between a single-ended tube design and single-ended transistor design. Yeah yeah, bias is different. But we both know that tube opamps proceeded solid state opamps, and tube power amps came before solid state power amps. Early solid state design merely mirrored tube design for the most part... anyhow, better to start with solid state stuff since you won't ZAPP urself. 😀
It's not bad advice actually, just somewhat dangerous for a newbie because of the high voltage. There's not really much difference between a single-ended tube design and single-ended transistor design. Yeah yeah, bias is different. But we both know that tube opamps proceeded solid state opamps, and tube power amps came before solid state power amps. Early solid state design merely mirrored tube design for the most part... anyhow, better to start with solid state stuff since you won't ZAPP urself. 😀
Cheers for your help guys.
Lot's of useful information to take on (basically buy books). I have a degree in Electronics but most of my course was geared towards DSP, Computer Networks, Design using Op-Amps. I am just interested in looking into how to design using SS and have already been looking into Valve designs.
Unfortunately, due to my location at the moment I do not have access to books or a any way of getting them here at the moment. That is why I was hoping for some good internet sources.
Thanks again
Mash
Lot's of useful information to take on (basically buy books). I have a degree in Electronics but most of my course was geared towards DSP, Computer Networks, Design using Op-Amps. I am just interested in looking into how to design using SS and have already been looking into Valve designs.
Unfortunately, due to my location at the moment I do not have access to books or a any way of getting them here at the moment. That is why I was hoping for some good internet sources.
Thanks again
Mash
Designing Analog Chips by Hans Camenzind The first half of his online book covers a lot of basic solid state circuit design.
You won't get off the hook so easily. There are such things as E- books, Kindle and others.
Many electronic design texts come in this form - travels with you, cheaper that new book prices, weighs nothing etc. etc.
Small Signal Audio Design: Amazon.co.uk: Douglas Self: Books
Yes that is true Ian, I have brought Valve Amplifiers Morgan Jones before it became under review by amazon for bad formatting (which I agree with). I have looked at others and a few reviews mention the same problem with formatting so I am a bit wary of spending ~£40 on a book that is un-readable.
get yourself a copy of the book, "Art of Electronics" Horrowitz and Hill...The Art of Electronics - Wikipedia, the free encyclopedia
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