Wanting to learn about tube pre-amp design....

[caps]

i can think of a better place to ask for links than here. :grin:


I am wanting to learn the basics of tube pre-amp design. Starting from the very very basics. In the future I would like to work on my own designs. I have built a couple of G9's , GSSL's etc, and want to actually start understanding tube pre's specifically, with a view to designing my own down the track.

So, any info that can be provided, remember starting at the basics, would be very much appreciated !

 

[Emperor-TK]

Buy "Valve Amplifiers" by Morgan Jones. Not a fast read by any means (I've only gotten through about 60 pages in the past couple months), but everything that's in there is worth digesting. Not overly theoretical, but not too dumbed-down "for musicians" either. For example, he will say stuff like (paraphrased quote) "square waves are a superposition of sine waves, where the relative energy of the component sine waves decreases with increasing harmonic number. They can be represented by the following Fourier series, but that's not really important. The square wave is an important test function for audio gear for these three reasons....".


-Chris

 

[kiira]

[quote author="caps"]i can think of a better place to ask for links than here. :grin:


I am wanting to learn the basics of tube pre-amp design. Starting from the very very basics. In the future I would like to work on my own designs. I have built a couple of G9's , GSSL's etc, and want to actually start understanding tube pre's specifically, with a view to designing my own down the track.

So, any info that can be provided, remember starting at the basics, would be very much appreciated ![/quote]

I would read these tutorials and learn how to do the math for a simple grounded cathose triode gain stage from them by learning how to figure a load line, derive characteristics like Gm from data and then plot an operating point that will give componennt values.

http://grace.speakeasy.org/~jsn/remote-images/
http://www.audioxpress.com/resource/audioclass/index.htm

here's a couple more good ones

http://www.radau5.ch/basics_1.html
http://members.aol.com/sbench101/

This is corny but teaches you some load line stuff
http://www.diyparadise.com/tubeloadline/tubeloadlines.html

Then I would get this program (unless you are a math genius) , and make a copy for me,and study the examples and then bug people here with questions when you get stuck.

http://www.glass-ware.com/tubecad/TC_Tube_Circuit_Descriptions.html

I would also have Tube Amplifiers by Morgan Jones and A Beginners Guide to Tube Amplifier Design by Bruce Rozenblitt. Both have their flaws but after you read them 100 times you will start to undertand tube design. LOL.

I also just keep re-reading things I didn't understand before, for instance Paul's article on building the Jimmy pre in audio xpress. Each time I re-read it, I understand better - mostly from absorbing information here.

Good luck!

Kiira

 

[analag]

First rule...high voltage is dangerous to your health.
That my friend is the first rule to tube electronics, the rest will follow.

 

[PRR]

> learn the basics of tube pre-amp design

Radiotron Designer's Handbook, Third Edition, P. Langford Smith, 1941. Start at the very beginning. The first half-dozen chapters teach you tube-amp basics. Skim or skip the strictly-radio chapters. There is some good audio stuff near the end, and important appendixes.

You may have to supplement this. Langford Smith leaves out some "common knowledge" that isn't so common today. There are about a million pages in other books that expand on what Langford Smith covers (including L-S's magnum opus The Fourth). But once you get the general idea of working with tubes, you CAN build a fine preamp with no other reference than Langford Smith Third.

It can't be read in a sitting. I've been reading the Third for 40 years. Literally read the covers off my first copy. It reads better in the hand than in a PDF. Fortunately a vintage old-tech (printed) copy of the Third is not very expensive, very worth the cost.

 

[caps]

Thanks for all the info guys.


btw, does anyone here use visual spice? If so, what do you think of it ? Thinking of getting it to toy with some design ideas once I have learnt enough...

 

[BYacey]

If you are serious about learning and want to have a solid understanding, take PRR's advice. The Radiotron handbook is a fine publication. In the long run you will reap far more benefits from understanding the theory than fooling around with Spice. Spice is a tool that can be useful later when you understand what you are doing, but it won't give you the initial knowledge base to get you started in the right direction.

 

[Nele]

the grace.speakeasy.org link works better at this location (with images):

http://www.boozhoundlabs.com/howto/

 

[pmroz]

.
the online Neets modules are working for me (at present, solder monkey). That's Navy Electrical Engineering Training S? chool? ervice?
Very well-explained. They're at tpub... Don't want to link... a googl search for ' Neets modules ' is easy.
They cover a lot of ground. For tubes, start at 'diodes' or a little before.

 

[caps]

[quote author="BYacey"]If you are serious about learning and want to have a solid understanding, take PRR's advice. The Radiotron handbook is a fine publication. In the long run you will reap far more benefits from understanding the theory than fooling around with Spice. Spice is a tool that can be useful later when you understand what you are doing, but it won't give you the initial knowledge base to get you started in the right direction.[/quote]

Understand. Spice was only something I was thinking of way down the track. I will be getting stuck into all the info provided above for quite a while yet :0)

 

[Larrchild]

Plate Voltage will meet you more than halfway.
Learn to work when probing around, with one hand in yer pocket or at your side.
It will become subconcious later. This avoids the annoying Path Through the Heart problem from one hand on ground.


i like this book as a primer: http://www.powells.com/cgi-bin/biblio?inkey=4-1882580133-2

 

[northsiderap]

I was given the 'evil eye' many times when discussing tubes with my engineer mentors....

The first things they asked me were:

1) How long do you plan on waiting after power-down to touch the thing? (at least 5-10 minutes to be really safe.) Then again, these guys were throwing around tubes the size of my head... :shock:

2) How you gonna make sure you don't discharge a cap right through your heart :shock: (already discussed) They had a huge thick rubber mat underneath their wooden bench also... Doesn't help if you have one hand on the chassis though...

But then they told me to figure out for triodes:

1) Plate resistance & voltage drop based on load
2) How to cathode bias the grid based on projected signal input voltage

And the rest kind of fell into place with the help of Gyraf's web site, PRR's links, and all of the other helpful advice around here. I've found it helps to read multiple texts on the same subject, cuz I've found that some of the book-writers are notoriously bad at cluttering up their explainations of how things work.... Maybe they need to fill a page number quota or something...