Microphone preamplifier for d testing

[papacharly]

Hello. I am looking for a preamplifier diagram for balanced condenser microphones powered by batteries, since it needs to be portable. The requirements I need are that it has an input gain potentiometer and another to control the output volume that will go directly to the input of a headphone amplifier. The quality of the preamplifier is not critical. Since the project arises from the need to be able to listen to the most optimal placement of a microphone or pickup as a check on different instruments. This is just to find the best position. Once the correct position is achieved, the microphone will be connected to a professional audio console. This is where the audio process will actually be done.

 

[Voyager10]

The tricky thing here will be supplying 48V phantom power from a battery source, it'll involve some form of switch-mode step-up converter. There's a recent post here: Cloudlifter CL-1 Teardown + Custom PCB Build which gives the schematic for a Sennheiser MZA-14 phantom power adapter - it has step-up circuit based round a TLC555 as an oscillator.

An inexpensive, ready-made unit which does exactly what you want is the Zoom U-22 audio interface (U-22 Audio Interface). I have one, it has:

• XLR input for a microphone
• Switchable 48V phantom power
• Headphone output
• Gain control for mic preamp
• Headphone level control
• Powered by 2xAA batteries

It can monitor the signal from the microphone via the headphones without the need to plug it into a computer or other device. Realistically, you won't be able to build something like this for under $100.

 

[papacharly]

The tricky thing here will be supplying 48V phantom power from a battery source, it'll involve some form of switch-mode step-up converter. There's a recent post here: Cloudlifter CL-1 Teardown + Custom PCB Build which gives the schematic for a Sennheiser MZA-14 phantom power adapter - it has step-up circuit based round a TLC555 as an oscillator.

An inexpensive, ready-made unit which does exactly what you want is the Zoom U-22 audio interface (U-22 Audio Interface). I have one, it has:

• XLR input for a microphone
• Switchable 48V phantom power
• Headphone output
• Gain control for mic preamp
• Headphone level control
• Powered by 2xAA batteries

It can monitor the signal from the microphone via the headphones without the need to plug it into a computer or other device. Realistically, you won't be able to build something like this for under $100.

Thanks Voyager10. I hadn't thought of that. The Zoom U-22 really seems to be what I need. Cheap and without having to do anything. Thank you very much and Happy New Year.