hello all.
I've made this circuit below to fit inside a metal chassis. it is a balanced out preamp.
View attachment 63333
there will be an external psu that has no ground to the mains . just + -
inside the metal box will be :
1. 12v and a 5v regulator
2. A TL071 preamp for an electret mic that is powered from the 5v reg
3. an audio line driver to balance the preamp output, this needed dual rail power (fed from the 12v reg) so it has a floating ground
4. a molex connector on the PCB that will go to an xlr chassis connetor. this will send audio (perhaps 20 meters away) to an external mixer that has its own chassis ground and that is weaved along the balanced cable too.
the only mains ground i see here is that coming from the mixer. along the balanced cable.
the xlr cable will mate to the preamp chaiss , so i plan to join the mixer chassis ground to the preamp chasiss. but then the regualtors inside need to be kept insulated from the chassis? is this normal? or can the regulator grounds connect to the floating ground in a clever way?
I hope the eagle editor picture i made helps expalin a little better
any help would be appreciated.
: )
I've made this circuit below to fit inside a metal chassis. it is a balanced out preamp.
View attachment 63333
there will be an external psu that has no ground to the mains . just + -
inside the metal box will be :
1. 12v and a 5v regulator
2. A TL071 preamp for an electret mic that is powered from the 5v reg
3. an audio line driver to balance the preamp output, this needed dual rail power (fed from the 12v reg) so it has a floating ground
4. a molex connector on the PCB that will go to an xlr chassis connetor. this will send audio (perhaps 20 meters away) to an external mixer that has its own chassis ground and that is weaved along the balanced cable too.
the only mains ground i see here is that coming from the mixer. along the balanced cable.
the xlr cable will mate to the preamp chaiss , so i plan to join the mixer chassis ground to the preamp chasiss. but then the regualtors inside need to be kept insulated from the chassis? is this normal? or can the regulator grounds connect to the floating ground in a clever way?
I hope the eagle editor picture i made helps expalin a little better
any help would be appreciated.
: )
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