Im aiming for pushing 10 watts through a four ohm load speaker from a 30V supply.

That being said what sort of current/voltage should i be aiming for at the output.

from what i can gather

30V-2V(allowing for some voltage drops) = 28 Vpp

peak voltage = 14V

Power = V^2 / 2R= 98V/8 ohms = 12 Watts not entirely sure where the 2R comes from in this but have seen it on a few calculations?

current = 14V/4 = 3.5A or would i need to use 8ohms here again giving 14/8= 1.75A?

i also have some questions about the input stage.

i was planning on having it run from the line out jack of an ipod or similar.

when measured for a sine wave output this is around 0.475Vrms or 0.662Vrms.

Measured using a multimeter (very high impedance).

my input current is going to based on the input impedance im assuming? i was planning on putting a 10k pot at the input for volume control, how would i account for this variable resistance? should i just ignore it and and/or just use its lowest resistance value in series with the resistance of the initial transistor stage?

Any help would be greatly appreciated.

Will