hg_man
Well-known member
I've been working on putting together a circuit to buffer a piezo pickup, powered by phantom power. Several people suggested looking at Bo Hansen's DI:
http://web.telia.com/~u31617586/
For my own understanding and for making the PCB, I redrew it with the changes Bo suggests:
Now I have two questions, possibly related:
What are ZD1 and ZD2 doing? Why are the pointing away from each other? (Or did I misinterpret Bo's schematic?)
Why does Bo show +24V in the upper center? I would think that the voltage at this point would be +48V because it's being fed from the phantom power on pins 2 and 3, both of which are at +48V.
Your help in understanding will be MOST appreciated.
Alden
http://web.telia.com/~u31617586/
For my own understanding and for making the PCB, I redrew it with the changes Bo suggests:
Now I have two questions, possibly related:
What are ZD1 and ZD2 doing? Why are the pointing away from each other? (Or did I misinterpret Bo's schematic?)
Why does Bo show +24V in the upper center? I would think that the voltage at this point would be +48V because it's being fed from the phantom power on pins 2 and 3, both of which are at +48V.
Your help in understanding will be MOST appreciated.
Alden