Air wrapped transformers calculator - by Alessandro Coppi (Italy)
Modify these 6 values and click CALCULATE button. 
Final stage impedance -      (Ohm): 
Loudspeacker impedance -     (Ohm):  
Medium diameter winding  -    (cm): 
Secondary hanks -              (n):  
Weight inductance 100 - 1      (n):  1 = low  inductance, 100 = hi (default 3,5)
Weight resistance 100 - 1      (n):  1 = low resistance, 100 = hi (default 3)
Primary winding, number of coils (n) : Primary winding, wire diameter (mm) :
Secondary winding, number of coils (n) : Secondary winding, wire diameter (mm) :
Primary winding resistance (Ohm): Section of the hank (cm2): Section of all hanks (cm2):
Primary winding inductance (milliHenry): Reactance at 50 Hz (Ohm):
Total Resistance seen from load side * (Ohm): Max current for primary winding wire (mA):
Dim a (cm) : Dim b (cm) : Dim w (cm) : Measures (abw) reported to the design.
In order to increase the max current of primary winding wire, modify the value "weight resistance"
* "Total Resistance seen from load side" is the sum of the resistance of the secondary winding plus the resistance of the primary winding seen through the impedance ratio of the transformer.

This program is free for not professional scopes, the only demand is to communicate to me eventual tests, possibly with one photo of the work enlosed. The mail address is this autocostruire@virgilio.it the program is based on the formulas of Kordorfer, and according to my tests are reliable, but obviously, no guarantee is previewed and eventual damages deriving from the use of data calculate do not acknowledge, verify it, or use just risk. The secondary windings (if more than one) connected in parallel. In the case of push pull, preview a taken of current exactly to half of primary winding, and connect it to the anodic tension. Soon, Alessandro Coppi Autocostruire.it