• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Building Valve Amplifier from schematic

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#4
Or download a copy of the Radiotron Designers Handbook, edition 3 or 4 (RDH3.pdf, RDH4.pdf). You can get them as bittorrent.

They're more impenetrable than MJ, and they're old (as the hills), but they're more comprehensive, they're free, and you can get them NOW.

w
 
#7
nige838 said:
Hello,
I'm wondering if anybody can lead me to some information on how to determine component values for a class a SE amplifier from tube datasheets?
Click to expand...

You've already got a lot of good advice as to resources. What you're asking is basically not possible.

Doing solid state design by formula works just great for a variety of reasons. First of all, most solid state devices are inherently high gain, and circuit performance is relatively independent of individual device characteristics. It just doesn't matter what transistor you choose, so long as it can process the frequencies being fed it, unless you need some special characteristic for some specialized purpose.

It makes a huge difference if you stick a 12AU7 in a hole meant for a 12AX7 (and vice versa).

Secondly, every external terminal of a solid state device is connected to every other one internally. Therefore, you can count on any Si BJT to have a Vbe= 0.6V (nominal) (unless it's something very specialized).

You can have formulas like:

Id= Idss(1 - Vgs/Vp)^2 (JFET: Where the "source" and "drain" are simply connections to opposite ends of the same piece of silicon).

In a vacuum tube, every element is just hanging there in an approximation to free space, all doing their own thing. So you need access to plate characteristics and draw loadlines. There's no other way to get the job done, unless it's some very trial 'n' error, hit er miss, method that's time consuming, risks serious poofage, and probably won't come close to optimum results.
 
#8
Unless you're in it for the challenge alone, your best bet is probably to build an amplifier kit. Tubelab Simple SE is pretty fool-proof and would be a good place to start. You can always analyze the circuit once you get a feel for the theory.

+1 for Morgan Jones' book. The information is available elsewhere - and in some cases for free, but I still find that Jones' book "Valve Amplifiers" is $60 well spent.

~Tom
 
#9
ditto on the kit. nothing like a nice parts list, good manual with good pictures, a task list that list steps with check off boxes, and a nice non schematical layout diagram. I think DYNACO is the king of DIY amplifier assembly manauals. Building froma a schematic could get tricky.
 
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