What is the input impedance of an LA3A?
According to Cinemag, the B11178 is equivalent to their CM-2511 which is a 1:5/10 mic input transformer with 600R/150R:150K impedance. But the circuit loads the secondary with 39K which means the impedance on the primary is going to be more like 39K/150K*600 = 156 ohms. Actually with attenuation at it's maximum it could dip to as low as 108 ohms.
This can't be right. What am I missing?
According to Cinemag, the B11178 is equivalent to their CM-2511 which is a 1:5/10 mic input transformer with 600R/150R:150K impedance. But the circuit loads the secondary with 39K which means the impedance on the primary is going to be more like 39K/150K*600 = 156 ohms. Actually with attenuation at it's maximum it could dip to as low as 108 ohms.
This can't be right. What am I missing?