owel
Well-known member
I'm working an all discrete mic preamp that I plan to develop into a project Kit.
Here are some pics of my adventures.
Prototype #001 and #002. Number 001 above is just the line driver output stage. Number 002, I added the mic preamp input stage, plus the line driver output stage. Also rearranged components for prototype PCB#002. This is the 7th iteration of my PCB design layout.
Closeup.
Wired and ready. The piggytail potentiometer is only there temporarily. I'll replace it with a resistor ladder/selector switch to control gain. You can also see the phantom power switch, and -20dB pad switch. I didn't cut the wires of the Sowter transformers because I may use it for other prototyping and don't want to cut it short.
I've tested it with my cheap MXL mic, applied phantom power, and it works... sounds very nice too At present it's powered by 40VDC (because that's as high as my bench PSU can go... but this will be eventually powered with a single 48VDC PSU.
Here are some pics of my adventures.
Prototype #001 and #002. Number 001 above is just the line driver output stage. Number 002, I added the mic preamp input stage, plus the line driver output stage. Also rearranged components for prototype PCB#002. This is the 7th iteration of my PCB design layout.
Closeup.
Wired and ready. The piggytail potentiometer is only there temporarily. I'll replace it with a resistor ladder/selector switch to control gain. You can also see the phantom power switch, and -20dB pad switch. I didn't cut the wires of the Sowter transformers because I may use it for other prototyping and don't want to cut it short.
I've tested it with my cheap MXL mic, applied phantom power, and it works... sounds very nice too At present it's powered by 40VDC (because that's as high as my bench PSU can go... but this will be eventually powered with a single 48VDC PSU.