impedance matching

[georgethomson]

hi there

i hope someone can help i seem to be going round in circles.

i am trying to place a speaker box inplace of where there used to be a headset. i am planning to use an 8 ohm speaker and the headset was 180 ohms. does anyone know how to work it out or can some one do it for me???

many thanks in advance

[whoaru99]

Details of what you are connecting the headphone/speaker to may be helpful to give a good answer.

[georgethomson]

hi

thanks for replying

the info i have is the headphone impedance is 230 ohms (sorry i thought it was lower) the output level at 0.5v/1khzis 81dba. there is an amplifier that feeds the headphones, which i'm still planning to use and the data i have for that is freq range 63-1600hz -6db, amplification 200mV/200ohms at an input signal of 4mV/1Khz, supply voltage 15-27V and power consumption is 18mA at 27V.

i am planning to use a normal 4 inch 8 ohm speaker.

all the above data was taken of a data sheet so if there is any other infromation i can provide please let me know.

many thanks

[Karma]

HI,
Sorry to say, it won't work. Headphone jacks have series resistors in place to limit the current draw to prevent just what you are trying to do. If you connect a speaker it will play but at very low volume. Not a good idea. You could connect another amp to the jack. But what's the point?

Sparky