A transformer is only one ... impedance transformer, that is to say there is no question of the proper impedance of the windings, the impedance presented by the primary is equal to the connected load on the secondary multiplied by the square of ratio.

An example of a transformer with a transformation ratio of 20, its input impedance will be:

•Zp = 20 000 ohms pour Zs de 50 ohms Zp = 20 000 ohms 50 ohms Zs

•Zp = 10 000 ohms pour Zs de 25 ohms Zp = 10 000 ohms 25 ohms Zs

•Zp = 3 200 ohms pour Zs de 8 ohms Zp = 3200 ohms 8 ohms Zs

•Zp = 1 000 ohms pour Zs de 2,5 ohms, etc Zp = Zs 1000 ohms 2.5 ohms, etc.

Obviously, it is extremely important to respect the speaker connections to the proper terminals, otherwise it is completely the tube output stage door-to-fake!