Hey all,
I am helping a friend by building a small battery powered mic pre. He is using it for video projects, which involve a lot of field recording, away from a wall power source. Additionally, a lot of sources are quiet, such as conversations, etc with little background noise - so we wanted to keep the pre as quiet as possible. He will be using a Rode NTG-2 microphone, which is a shotgun style small diaphragm condenser, if you're not familiar. It can be powered by either external phantom power or internal batteries.
For the mic pre itself, I'm using the simple dual channel P66 Pre board available over at ESP.
I've attached my plan for the power supply and phantom powering method. First, does this look like it will work? I tried keeping things as simple as possible. The power supply is not regulated (which means headroom will sag as battery power goes down), which I chose to try and extend battery life. For resistor values, I will use 10k for the voltage divider circuit, 1%, matched as closely as possible. I'm guessing 1/4 W is enough here?
For the phantom power, I know that 6.8k is the normal value for the series resistors with P48 - does this matter if I'm using 9V instead? I have read that the value does not matter as much as the tolerance to which the resistors are matched.
Thanks for reading!
I am helping a friend by building a small battery powered mic pre. He is using it for video projects, which involve a lot of field recording, away from a wall power source. Additionally, a lot of sources are quiet, such as conversations, etc with little background noise - so we wanted to keep the pre as quiet as possible. He will be using a Rode NTG-2 microphone, which is a shotgun style small diaphragm condenser, if you're not familiar. It can be powered by either external phantom power or internal batteries.
For the mic pre itself, I'm using the simple dual channel P66 Pre board available over at ESP.
I've attached my plan for the power supply and phantom powering method. First, does this look like it will work? I tried keeping things as simple as possible. The power supply is not regulated (which means headroom will sag as battery power goes down), which I chose to try and extend battery life. For resistor values, I will use 10k for the voltage divider circuit, 1%, matched as closely as possible. I'm guessing 1/4 W is enough here?
For the phantom power, I know that 6.8k is the normal value for the series resistors with P48 - does this matter if I'm using 9V instead? I have read that the value does not matter as much as the tolerance to which the resistors are matched.
Thanks for reading!