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

[martinman]

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

[Diablo]

I don't think there is any such course that you can take. The best you can do is to get some good books and participate in the various forums like this one. I'd start with the Valve Wizard book, the author also visits this forum.

[martinman]

Diablo: Ha! Love it -- I didn't even know these existed. I'll definitely pick it up on amazon.

[Jazz P Bass]

Other than a rudimentary understanding of valve amplifiers, you need to study basic electronics.
If you need to know "why" a Marshall is a Marshall (or other amps), you need to study each specific amplifier that you are interested in.
They are all the same, they amplify.
They are all different. (fill in manufacturer, model number here).

[exclamationmark]

A knowledge of electronics will certainly help if you intend to actually understand how these circuits work. As for the rest, you can practically glean all that information from the valve wizard's book/website. The tricky thing about design is that while you can predict every parameter of your circuit, you can't predict how it will eventually sound! Certainly you can be pointed in the right direction, but most of the time you end up spending more time tweaking values than calculating.

[Chuck H]

but most of the time you end up spending more time tweaking values than calculating.

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.

[R.G.]

Reminds me of the "English castle lawn" story.

Some Ugly American Tourists were in Jolly Old, on the tour bus of country estates. At one country estate, the front lawn was simply magnificent - emerald green, billiard-table level and faintly sweet smelling in the way some lawns can be. One of the UATs was so smitten by the sight that he approached their Very Proper guide, and loudly asked
"Say, that lawn is beautiful. How you guys get it to look like that? I want to make mine look that good."

The VP guide, without turning a hair, said,
"Well, sir, you first prepare the earth, grading and aerating by tilling it. You do soil analysis to find out whether it needs fertilization, organic matter, or trace minerals. Once this is correct, you seed it, raking the seeds in, and keeping it just moist till the seeds germinate. Once it's tall enough to mow, you mow and roll it for 200 years.

[Chuck H]

Excellent.
Learning to design amps takes less time than that.

[diagrammatiks]

pentodepress.com

read the classic circuits. then read it again.

[mooreamps]

I personally found the TUT series from LondonPower to be the best books written on this subject... I've read them over, several times over when I bought them... Highly recommended.....

-g

[martinman]

Thanks everyone for the replies. I have the Valve Wizard book on order.

Are the TUT books really worth it? $80 is is a ton of money for a ringed binder. Can I buy it in PDF?

[Amp Kat]

I personally found the TUT series from LondonPower to be the best books written on this subject... I've read them over, several times over when I bought them... Highly recommended.....

-g

You beat me to it g and although I have learned so much from the great posters of Ampage which btw I refer to as Ampage University (thanks t-boy) the O'Connor books mainly the 1st one THE ULtimate Tone are a really nice source however if you don't already know electronic basics don't even bother however Kevin has an entry level book called "Ready Set Go" that has some nice basics in it and ohms law theories to learn and then you'll be ready for TUT 1 and yes that book is worth the $80. The newer books cover more of the Power Scaling and mixing of Solid State and Tubes Hybrids stuff.
What is so good about TUT is it has lots of preamp topologies and shows how the -3dB down point is calculated.

Two of the most useful pieces of info I've also ever read on the web are Randall Aikens
Technical White papers which teach you how to design common cathode amplifiers to the degree of engineering which is what it basically is at that point. The other is RG Keens Geofex site that has lots of very useful info on it about amps and effects. There is alot you can find on the web without even purchasing a book to get you started unfortunately Aikens site is under constuction right now but when it's done should be even better I would think.

[mooreamps]

Kevin's books are the only one's which impressed me the most...

-g

[Tom Phillips]

Are the TUT books really worth it?

Yes. You will learn more every time you read and re-read them.

$80 is is a ton of money for a ringed binder.

That's a true statement. If you just want a ringed binder you can probably get one for $1 at your local office supply store.
Obviously you are paying for a lot of time and effort that went into the books plus a fair profit.
The TUT series isn’t just a download of recycled material either. The books have the fewest typos compared to similar publications which shows that they were well proof read.

[JoeM]

Thanks everyone for the replies. I have the Valve Wizard book on order.

Are the TUT books really worth it? $80 is is a ton of money for a ringed binder. Can I buy it in PDF?

Who ever said the cost of education was cheap?

You're getting reference material that you can use for a long time. Cheaper than most college textbooks too.