how to make audio output transformer

[circuitravi]

I want to make an audio output transformer for tube amplifier. So I want to know, how to calculate turns, impedance and watts? Is there any software for this? thanks!

[mnturner]

Google pat turner's website for some pretty comprehensive info

[Miles Prower]

Have a *.pdf of the Wolpert Audio Xfmr Design Manual, but it disappeared off the 'Net. I could sent a copy attached to an e-mail (too big to attach here).

[LinuksGuru]

For the beginning, Wolpert's book is enough. For more advanced design, you need to calculate and check resonant frequency based on leakage inductance and capacitance (inter-turn / core-1st layer / primary-secondary). And check for permeability levels under small DC BIAS always present in PP amps.

[LinuksGuru]

Originally Posted by circuitravi

I want to make an audio output transformer for tube amplifier. So I want to know, how to calculate turns, impedance and watts? Is there any software for this? thanks!

I have this software. Post your objective, core data, and I will reply with results.

[Yvesm]

Wolpert's paper:

http://www.dissident-audio.com/Trans...ign_Manual.pdf

Software:

http://www.dissident-audio.com/Trans...and-OPT.tar.gz

Have fun !

Yves.

[lt cdr data]

wow, transformers are fascinating animals, but highly highly complex and its not recommended for newbies to even go close to this sort of thing.

if you want to know a bit, here's some info....its much easier to buy one!!

for se, primary turns is 33 times root of (impedance )

for pp its 44 x the same.

use interleave of 0.6mm insulation, plastic, and layer it pspsp

simple as that really.

eg single ended 2500 ohms primary

turns = 33 x root of 2500 = 33x 50 = 1650 turns, 5 layers prim, sec, prim, sec, prim.

not sure about air gap, there is SOME info on the web.

the primary turns is a simplification of the classic transformer equation, viz.

B= (1.10 ^8 x volts) / 4.44 x Frequency x Area x turns.

where b = ac flux, I have used 8000 here

frequency = 20 hz

Core area = 450 x root power out in mm squared.

rearrange to get turns and it will simplify to the equation given, by a bit more maths.

use core area above to find size of core.

that's all you need, viz.

turns
size of core
interleave pattern

and air gap, the load is your own value and not given here. depends on the tube you are using.

the primary turns value is foolproof,

go here for more info. best site bar none for tx info its really pitiful the web for this sort of thing

http://www.turneraudio.com.au/se-output-trans-calc.htm

[Yvesm]

Originally Posted by lt cdr data

for se, primary turns is 33 times root of (impedance )

for pp its 44 x the same.

use interleave of 0.6mm insulation, plastic, and layer it pspsp

I suggest p/4,s,p/2,s,p/4, this reduces linkage inductance by a factor of (at least) 4.

Yves.