*Really* understanding... and getting into design.

[R.G.]

Education is always expensive.

Often, money is the least expensive way to pay for it.

[martinman]

Education is always expensive.

Often, money is the least expensive way to pay for it.

Quite a nice way to sum things up. I'm going to use this in the future if you don't mind. Great quote!

[Alan0354]

This is exactly what it takes. Some electronics knowledge is critical for reasons like setting up ground schemes, knowing how to do a layout, figuring for component ratings, etc. But to get to the "sound" of an amp it doesn't really help to know "what" a particular capacitor value does. You need to know how it sounds. You can "know" that a higher value capacitor will pass lower frequencies, but you can't know how that will sound until you try it. Trying different things with different circuits will start to become intuitive. That is, you will be able to hear what a given component value does as you change it and learn to recognise the effect. Eventually getting an idea where and what to change in an amp just by listening. All this with the caveat it applies to the sound of an amp and you obviously must know enough actual electronics to keep operating conditions within safe parameters. The design end assumes that you already know how and why a basic amplifier circuit works, what the components do and why it doesn't explode in flames. Now you will be shaping sound and performance characteristics to make the amplifier circuits work as an instrument.

Definitely read books to get the tech part in your cranium. But also, start tweaking the amps you already built. If there is anything you would like to improve or change about the performance or tonal character of any of your amps do some research here, or ask questions. As you make changes your awareness of what changing component values does will improve and you'll get closer to being able to speculate designs. Along the modification path you'll be forced to learn more about component rating, formulas for figuring the knee frequency of a capacitor at a given impedance, how to calculate voltage drops, etc. And you'll hear the effect in what you do and be able to apply it later without the need to try twenty different values of a given component.

Just like building a guitar from parts inspires the desire to design one from scratch, likewise with amplifiers. But to make a guitar from scratch you need carpentry understanding and skills, some exposure to the tonal properties of different woods, knowledge of glues, an understanding of scale length and where to position frets, some basic structural and engineering know how, etc. Likewise with amps.

Exposure to the process by doing mods is a great way to start IMHO. Books are essential for understanding and safety. But most important... Don't forget to play your guitar because your always obsessing about the tone It happens.

Good explanation.

I think it is important to learn basic circuit theory and even learn transistors and op-amp. Particular transistors in ways work similar, you need to learn basic biasing and basic gain stage. But this particular amplifier field where good distortion is better, a lot of formal electronics theory don't quite cover this. Experiment and observation is just as important. Actually I am spending time observing how different bias, different head room change the characteristics of the sound and how different distortions really sounds and try to get a feel of the electronics. This is where a lot of text book theories are out the window so to speak.

[Alan0354]

Hi Everyone,

I'd like to better understand the 'why' of amp design. Why is a marshall a marshall? Why does a 5e3 sound the way it does? And on and on. I built a few amps over the years - a 5f1, 5e3 and a p1 from ax84, and I've done fairly well with assembly and troubleshooting. What's the best way to get to the next level and actually design something? For instance: what would a 5e3 sound like with only 1 6v6 (will it sound like a 5f1?). What about a 5f1 with 5e3 type inputs and channel mixing? etc...

I'm looking for something like a weekend apprenticeship program, or classes at a college. There just doesn't seem to be anything out there like this (at least in Michigan).

Basically, I feel pretty confident in building the kit variety of amps, and I want to get to the next level. What's the best way?

Thanks!
Mark

If you are interested in electronics, you should enroll in electronic classes starting with basic circuit. Look at the description of the classes and enroll to those at your level. It is always good to learn more.

But if guitar amp is all you want, I don't think there are any particular class that deal directly into this. But you'll see things quite differently if you have a good basic electronics background. Even tube amps have frontend preamp, a differential stage ( phase splitter), a power supply and a power amp stage. This you can learn in school. By learning the calculation, it make you better prepare to design your own. I strongly encourage you to give the classes a try and see where it leads you. I did and I owe thanks to my first Fender Twin that got me into my fulfilling career life.

I started out as a tinkerer and modify amps in the 70s. I started learning electronics at the time and the more I learn, the more I fell in love with electronics that I quit playing in 79 and went on a full career of EE for almost 30 years. You never know what window it'll open for you. Now I am not working, but the love of electronics still drive me to study 15+ hours a week for the last 10 years, not for work, but for myself.

[Chuck H]

Good explanation.

I think it is important to learn basic circuit theory and even learn transistors and op-amp. Particular transistors in ways work similar, you need to learn basic biasing and basic gain stage. But this particular amplifier field where good distortion is better, a lot of formal electronics theory don't quite cover this. Experiment and observation is just as important. Actually I am spending time observing how different bias, different head room change the characteristics of the sound and how different distortions really sounds and try to get a feel of the electronics. This is where a lot of text book theories are out the window so to speak.

Yup. Any formal electronics information does no justice to understanding how to make clipping and overdrive musical. Distortions are always managed with respect to eliminating them with little other regard.

It was recently speculated in another thread that one reason tube amps are percieved as superior in tone is that the simple circuits possible with tubes, and used in the early designs, naturally create more musical distortions. So, basically, you can crank up almost any tube amp and it'll be more musical than transistors. So, this doesn't make tubes superior per se, but it does mean that it's easier to make a tube distort in a useful way than a transistor. Funny that these stereo types on the two technologies, tube vs. transistor, has perpetuated for so long without being properly analyzed and understood. Easy to say though since that would be a task outside my range of tools and skills.

[loudthud]

If you are interested in electronics, you should enroll in electronic classes starting with basic circuit. Look at the description of the classes and enroll to those at your level. It is always good to learn more.

I never understood how feedback worked until I studied opamps and solidstate power supply regulators.

[Alan0354]

I never understood how feedback worked until I studied opamps and solidstate power supply regulators.

Yeh, the feedback loop in tube amp is not that obvious, you have to look for it. It is from the secondary of the OPT back to mostly the differential stage. And if people are not careful, it can cause instability. I remember in the 70s, I don't know anything about it, I hooked up the feedback on the opposite lead by mistake late at night and turn on the amp!!!! Did I waked people up and startled me!!!!

It's those knowledge that don't directly help in the guitar amp, but it sure help you understand deeper. Those tube amp in a very twisted way, actually some what like an opamp!!! You have the phase splitter tube that is mostly in differential amp configuration.( I've seen one or two actually use half the tube and put equal resistors at cathode and plate to get gain of one both opposite polarity between both sides). That is like an opamp that has differential input stage.

[Gingertube]

There is a lot of stuff (Knowledge) which is specific to guitar amp design.
I am a Senior Electronic Design Engineer in the day job so have a good fundamental electronics knowledge and theory base.
When I got into tube amp design for a hobby I did about a dozen tube HiFI Amp designs and builds. When I started on Guitar Amp design it was often a matter of what things I would atuomatically do in a HiFi design that are of no benefit or worse of negative benefit in a Guitar Amp. I found the Kevin O'Connor TUT Series invaluable (I have the entire set) and have just ordered Merlin Blencowe's two books. These sit on my bookshelf alongside the "high browe" highly technical (and mathematical) reference books. If you are looking for a "library" of schematics then the Aspen Pittman book is good but be seriously aware that the technical section on amp mods etc. is "not up to snuff" and contains some stuff which is not just wrong but likely to cause serious problems if implemented (As an example they say that the 12DW7 in an Ampeg can be replaced by a 12AX7 without any other mods - that is seriously BAD advise).
My other source of Guitar Amp. "knowledge" (or more importantly Guitar Amp. "experience") is right here.
I got my current day job (20 years ago) from a very astute fellow - he told me what he liked about my work was that it did not matter if I did'nt have all the necessary knowledge, he liked my attitude of "dive in and have a go". Treat each screwup as a "learning experience" and before you know it you too will be an "expert".
The thing about Guitar Amps is that they are a "musical instrument" in their own right. What "sounds" best does'nt necessarily align with accepted theory, in guitar Amp design that means that you have the wrong theory or a wrong understanding of the theory.
Cheers,
Ian

P.S. (Late Edit) A good proportion of your Guitar Amp Sound comes from the speaker. Don't cut corners or "pennies" on this vital part of your amp.

[Alan0354]

There is a lot of stuff (Knowledge) which is specific to guitar amp design.
I am a Senior Electronic Design Engineer in the day job so have a good fundamental electronics knowledge and theory base.
When I got into tube amp design for a hobby I did about a dozen tube HiFI Amp designs and builds. When I started on Guitar Amp design it was often a matter of what things I would atuomatically do in a HiFi design that are of no benefit or worse of negative benefit in a Guitar Amp. I found the Kevin O'Connor TUT Series invaluable (I have the entire set) and have just ordered Merlin Blencowe's two books. These sit on my bookshelf alongside the "high browe" highly technical (and mathematical) reference books. If you are looking for a "library" of schematics then the Aspen Pittman book is good but be seriously aware that the technical section on amp mods etc. is "not up to snuff" and contains some stuff which is not just wrong but likely to cause serious problems if implemented (As an example they say that the 12DW7 in an Ampeg can be replaced by a 12AX7 without any other mods - that is seriously BAD advise).
My other source of Guitar Amp. "knowledge" (or more importantly Guitar Amp. "experience") is right here.
I got my current day job (20 years ago) from a very astute fellow - he told me what he liked about my work was that it did not matter if I did'nt have all the necessary knowledge, he liked my attitude of "dive in and have a go". Treat each screwup as a "learning experience" and before you know it you to will be an "expert".
The thing about Guitar Amps is that they are a "musical instrument" in their own right. What "sounds" best does'nt necessarily align with accepted theory, in guitar Amp design that means that you have the wrong theory or a wrong understanding of the theory.
Cheers,
ian

Yeh, I also a long time EE that started with tube guitar amp in the 70s and just came back a few months ago. The more I look into this, the more I found the devil is in the detail rather than a revolution. It is a totally different animal and the bias point etc. make a day and night difference. In EE work, you mostly deal with linear, but in here, it's about the best distortion and just the right amount!!! There is a lot of experiments and practical observation involve. I am still trying to adapt to this mentality.

[Amp Kat]

There is a lot of stuff (Knowledge) which is specific to guitar amp design.
I am a Senior Electronic Design Engineer in the day job so have a good fundamental electronics knowledge and theory base.
When I got into tube amp design for a hobby I did about a dozen tube HiFI Amp designs and builds. When I started on Guitar Amp design it was often a matter of what things I would atuomatically do in a HiFi design that are of no benefit or worse of negative benefit in a Guitar Amp. I found the Kevin O'Connor TUT Series invaluable (I have the entire set) and have just ordered Merlin Blencowe's two books. These sit on my bookshelf alongside the "high browe" highly technical (and mathematical) reference books. If you are looking for a "library" of schematics then the Aspen Pittman book is good but be seriously aware that the technical section on amp mods etc. is "not up to snuff" and contains some stuff which is not just wrong but likely to cause serious problems if implemented (As an example they say that the 12DW7 in an Ampeg can be replaced by a 12AX7 without any other mods - that is seriously BAD advise).
My other source of Guitar Amp. "knowledge" (or more importantly Guitar Amp. "experience") is right here.
I got my current day job (20 years ago) from a very astute fellow - he told me what he liked about my work was that it did not matter if I did'nt have all the necessary knowledge, he liked my attitude of "dive in and have a go". Treat each screwup as a "learning experience" and before you know it you too will be an "expert".
The thing about Guitar Amps is that they are a "musical instrument" in their own right. What "sounds" best does'nt necessarily align with accepted theory, in guitar Amp design that means that you have the wrong theory or a wrong understanding of the theory.
Cheers,
Ian

P.S. (Late Edit) A good proportion of your Guitar Amp Sound comes from the speaker. Don't cut corners or "pennies" on this vital part of your amp.

I could see where TUT books could be unvaluable to an EE because most of you guys need either formulars or load lines to make any sense but we are talking about a student that has no electronic schooling so they could be benificial to this person. I agree that the best way to learn is to dig down in to it but as a starter you have to have a foundation to start with and they don't teach tubes in EE school so it's either a book, on here or the net somewhere.

Kevin does discuss distortion generation techniques,clipping,bounding and bandwidth calculations in TUT 1 book. Not saying the books are exactly what he needs to learn everything but they are good for an intermedite student who wants to learn some tube and transistor stuff along with tube power amp knowledge you will never learn at EE school.

[R.G.]

Learning is a series of platforms. If you don't have the base to reach the concepts, you will not be able to grasp them.

A course in the poetry of Keats and Byron won't mean much if you don't understand English. A course in calculus won't mean much if you can't do arithmetic. A course in tube amps won't mean much if you don't understand Ohm's law, RLC circuits, and elementary filter concepts, and won't help you design killer tube amps if your previous learning is entirely computer logic in the EE curriculum.

That is, you prepare the seed bed, seed, water, then mow and roll it for 200 years. Not knowing what a seed is, what level means, or how to run a mower and roller will hold you back a lot. Knowing the fine, esoteric details of fertilizer theory won't be enough.

[Chuck H]

Knowing the fine, esoteric details of fertilizer theory won't be enough.

Indeed... The cork sniffers on the hi fi forums are well versed in fertilizer theory.

[Alan0354]

Education is always expensive.

Often, money is the least expensive way to pay for it.

I always buy used books on Amazon. My experience is the used books are like new in most case......one or two were quite bad. Books are so expensive to buy new. particularly I tend to buy older editions. They can be very very cheap.

[martinman]

Hi Guys,

Just wanted to check back in -- I received the Valve Wizard book today. I understood about 1/3 of what was discussed... And by understood, I mean recognized some of the vocabulary!

TUT book #1 is on order. But I think I need to get a better understanding of basic circuits first. Maybe a community college class might do it - I'll look into this as well!

The valve wizard book is probably a 2nd level text to read once you get the basics down. It's definitely something to keep around though -- there is a great section on construction and the first 2 chapters are great too. But to really get the most out of the entire book, I think I need a class (learn by doing) to review the basics.

[Tom Phillips]

...I need to get a better understanding of basic circuits first...

My suggestion is that you download the Basic Audio series by Norman Crowhurst. The three volumes are available through the web page at Technical books online. The series doesn't cover special considerations for guitar amps but it's not audiofool weirdness either. Just good basic info. And it's free. Sorry I din't think of this earlier.
Regards,
Tom