deb611
Member
A friend asked me to fix his SM7B. It just had a broken solder joint, easy-peasy.
I found the wiring diagram and it took me a second to try to sort out what was going on.
Someone please tell me if I'm understanding this right, just for my own curiosity.
The ROLLOFF:
When the bass rolloff switch is ON (down), it appears to simply insert a 260mH inductor across pins 2 and 3. An inductor's impedance increases with frequency, meaning that the low frequencies will more easily cross between pins 2 and 3. This essentially causes phase cancellation at lower frequencies across the output pins, but higher frequencies are far less affected as the impedance rises across the inductor at high frequencies.
The PRESENCE BOOST:
it seems like the presence boost turning ON (up) is just removing an LC series bandstop filter, right? The .22uF capacitor and 11mH inductor are connected in series across pins 2 and 3, creating a bandstop filter. When the presence switch is turned "on", these are disconnected and allow the capsule's actual voicing to come through.
I found the wiring diagram and it took me a second to try to sort out what was going on.
Someone please tell me if I'm understanding this right, just for my own curiosity.
The ROLLOFF:
When the bass rolloff switch is ON (down), it appears to simply insert a 260mH inductor across pins 2 and 3. An inductor's impedance increases with frequency, meaning that the low frequencies will more easily cross between pins 2 and 3. This essentially causes phase cancellation at lower frequencies across the output pins, but higher frequencies are far less affected as the impedance rises across the inductor at high frequencies.
The PRESENCE BOOST:
it seems like the presence boost turning ON (up) is just removing an LC series bandstop filter, right? The .22uF capacitor and 11mH inductor are connected in series across pins 2 and 3, creating a bandstop filter. When the presence switch is turned "on", these are disconnected and allow the capsule's actual voicing to come through.
