Amp design tutorial

R

rodiond

Member
A newbie user here. I am starting to realize that I need to understand the inner workings of tube amps in order to get the most out of my Axe. So I am looking for tutorials on how tube amps work. Things like gain stages, negative feedback loop, tube bias, tone stack, cathode follower, etc. I would like to get a pretty thorough understanding of some common amp designs schemes, not just a high level overview. It would also be great do see how these concepts are implemented in real-world amps. Finally, would be great to understand how these concepts map to Axe-Fx algorithms and parameters.
Any links and resources are greatly appreciated.
Hope I am not asking for too much :)
 
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The old Tube Amp books by Aspen Pittman helped me a lot when I was first getting into modifying amps and building clones.

It's a basic overview, not an in-depth analysis of tube amp design, but it would give you a taste...and lots of schematics.
 
I would wager probably 99% of users don't know what most of that stuff does and still get plenty of enjoyment and great tones out of their units. Its fine and good if its of interest to you, and can be fun of course, but generally just selecting an amp model, adjusting the basic tone stack (if that even) is all one needs to do to get great tones
 
rodiond said:
A newbie user here. I am starting to realize that I need to understand the inner workings of tube amps in order to get the most out of my Axe.
Click to expand...

Is that really true? I suppose it depends on what your actual goal is.

So I am looking for tutorials on how tube amps work. Things like gain stages, negative feedback loop, tube bias, tone stack, cathode follower, etc. I would like to get a pretty thorough understanding of some common amp designs schemes, not just a high level overview. It would also be great do see how these concepts are implemented in real-world amps. Finally, would be great to understand how these concepts map to Axe-Fx algorithms and parameters.
Any links and resources are greatly appreciated.
Hope I am not asking for too much :)
Click to expand...

I would start at the wiki, http://wiki.fractalaudio.com/axefx2/index.php?title=AMP_block_parameters
http://wiki.fractalaudio.com/axefx2/index.php?title=Amp:_all_models
And Yek's guide:
https://dl.dropboxusercontent.com/u/10338746/Yeks_Guide_to_the_Fractal_Audio_Amp_Models.pdf

Just as a starter before diving into more technical territory.
 
AlbertA said:
Is that really true? I suppose it depends on what your actual goal is.
Click to expand...
I think it depends quite a bit on the personality of the individual. Some people like to have detail "why" questions answered before they feel comfortable with the thing they are trying to explore more, while others feel bogged down by such details and prefer to let the chips fall where they may and just go for it.
 
groovenut said:
I think it depends quite a bit on the personality of the individual. Some people like to have detail "why" questions answered before they feel comfortable with the thing they are trying to explore more, while others feel bogged down by such details and prefer to let the chips fall where they may and just go for it.
Click to expand...

That sums up both the joy and sometimes agony of Fractal users! :) Parameter nirvana or paralysis.
 
Turn dials see how things sound. It is literally the only way. Even if you know everything about what a parameter is SUPPOSED to do, can you really know what is sounds like until you turn the dial! Im not knocking your interest but I find the same parameter will make different amps/ir's react differently. Without knowing an extreme amount about A PARTICULAR AMP (eg. you already own a 5150), Id say turn the dials.
 
Tweaking is fun, and picking a bit at a time and exploring how it changes the sound probably isn't going to make anyone's head explode.

On the other hand, I think the models are so good right now that you can just pull one up and get a great tone just by twiddling the knobs that correspond to the ones on a physical amp.
 
AlbertA said:
rodiond said:
I am starting to realize that I need to understand the inner workings of tube amps in order to get the most out of my Axe.
Click to expand...

Is that really true?
Click to expand...
Yes, it's true.

Don't get me wrong. You can get stellar results out of the Axe without understanding the inner workings of tube amps. But to really get the most out of it, you need to know what's being modeled. What goes on inside an actual amp. What settings interact with other settings, and how they change each other's behavior. If all you do is turn dials back and forth and see what you like best, you might never discover some of those interactions.

The Axe delivers in spades, whether you know how tube amps work or not. But the more you know, the more it reveals.
 
Thanks a lot for all the suggestions! This is very helpful.

I agree that you don't have to know how amps work to find a good tone. However, being a technical kind of person I prefer to have some idea of what happens when I turn a certain knob. Also, while reading Yek's tutorial as well as some of the Cliff's comments, I realized I don't understand half of them because of the technical terms. That's another reason.
 
Probably more important as a fractal user is understanding how classic tones are achieved with drive pedals, how to set certain types of amps and effects, etc. it is a science unto itself
 
One of the most overlooked components is the cab. You can tweak that amp until the cows come home but if the cab is not right then you are literally going to struggle. I would say the cab actually affects more than half of your tone; so it's a case of finding the right cab for you first by messing around with different cabs on an amp block with default settings, and then tweak the amp block.
 
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