Speaker => line out matching (packet radio)

[Blue Dog]

I'm building a packet interface for a amateur radio, the tranceiver doesn't have a line out and the schematic calls for a 1k-8ohm transformer for the match, the closest I can find locally is 1k2 - 8 - any thoughts on this?

VE3GKN

 

[audioguru]

A 1k to 8 ohms transformer will attenuate a 2V signal 11.2 times to 179mV.
A 1.2k to 8 ohm transformer will attenuate the 2V signal to 163mV.
The difference is only 1dB which is not noticeable.

Why a transformer? Why not two resistors instead?

 

[Blue Dog]

Thanks for confirming my suspicions and for knowing/doing the math
I think the matching transformer is being used to eliminate any potential ground loop hum on the signal and more importantly, to reduce the risk of any damage to the computer or radio from any difference in voltage potential - guess it does double duty by acting as an isloation transformer as well as doing the match.