K1803 Building a mic pre-amp to connect a cond. mic to XLR

I’m looking for a solution for connecting a simple condenser mic like those used on computers (probably 5V power) to an XLR connection on a mixing interface. Since the mic needs 5V power and the interface does not provide 5v power, I need to provide it inline. Ideally I’d like to build a little box that takes as input a microphone with a 3.5mm mini connector and outputs to a XLR male connector for connection to the mixer, running on a battery pack (probably 4 AA batteries).

I came across this Velleman “Microphone Preamp Kit” on Parts Express:

partsexpress.com/pe/showdetl … er=320-204

I assume this is the K1803 Universal Mono Pre-Amplifier?

Assuming this is the right part to use for what I need, what else will I need to put this pre-amp together?

If this isn’t what I need, can someone suggest an alternative?


XLR is a balanced signal. Electret mike and K1803 is unbalanced.
You need a dedicated circuit, not available from our range.

So then let’s say I connect it to a TRS connector instead, what would I need?

Here’s how to connect an electret

So you’re saying the K1803 kit is the correct kit for connecting a computer mic to a mixer using an unbalanced connector? Is there anything else I need other than the K1803 kit? Is a 4xAA battery pack good, or is it better to go with a 9V battery (since your diagram shows a 9-12V power supply)?


No, I did not say that. Probably, you do not even need a pre-amp.
9V battery would be a good choice.

Sorry, I’m a bit confused. I’m new to working on circuits like these. Can you spell out which parts I need? Thank you.

Final attempt :slight_smile:

You need the parts shown on the diagram and a 9V battery + battery holder.