Can somebody provide me with well written out formulas for finding impedance change in the output transformer. I am designing a tube amp and need to find out what transformer ratio i need. Help is greatly appreciated!
The impedance ratio varies as the square of the turns ratio.
Getting turns ratio right is a small part of the problem. The inductance of the primary must be sufficient to yield good bass extension.
What O/P tube are you planning on using?
Getting turns ratio right is a small part of the problem. The inductance of the primary must be sufficient to yield good bass extension.
What O/P tube are you planning on using?
The only answer to this question is: "it depends". You're very short on specifics. Otherwise, the only formula is:
Zsec= Zpri(Nsec/Npri)2
When designing impedance transformations, the usual practice is to make XL >= 5RL at the lowest frequency of interest. That's the usual RF matching xfmr design practice where it's not a difficult standard to meet. For audio practice, where frequencies are a good deal lower, and high inductive reactance means lots of iron and copper, the design is to make XL at least equal to the resistance. For sonic performance, the more L the better (up to a reasonable amount, usually ~50H).Speaker loads aren't pure resistances, and loadlines aren't the nice, straight lines you see with RF amps working into low-SWR T-lines where you can always tune out the reactive components.
As for the actual resistance transformations involved, that varies considerably from the SE case, to Class A push-pull, to Class AB PP. (or Class B or Class C, but not relevant to audio).
If you have a 32 bit PC, why not try YvesM's Output Transformer design program....?
All that complicated number-crunching done for ya! Change one parameter--and you can see exactly what else changed....
You'll find it on his website,-- dissident audio. Its called, Opt.Da I believe he uses it himself in trans. making and turns out some very nice amps with his own transformers....
All that complicated number-crunching done for ya! Change one parameter--and you can see exactly what else changed....
You'll find it on his website,-- dissident audio. Its called, Opt.Da I believe he uses it himself in trans. making and turns out some very nice amps with his own transformers....
Hi,
I have a little writeup that I made to another case, but it may help you.
All comments to this is appreciated
I have a little writeup that I made to another case, but it may help you.
All comments to this is appreciated
Great interest your exposure, please continue, I think is very helpful.
Being a forum for vacuum tube electronics section, output transformers are the most important parts of a vacuum tube amplifier.
It says "no vacuum tube amplifier with better than his output transformer ..."
Thank you!
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