ELF/VLF Pre-Amp partial kit – $27
Being new to the group and ELF/VLF in general, I was impressed with the simplicity of Peter’s (VK2AN) ELF pre-amp circuit he posted in the vlf.io group. I contacted him and asked if I could make a partial kit available to the interested community. After many emails, he helped me to to understand the unique orientation and requirements of mounting the TI LMP7721 Femtoampere Precision OpAmp on a pcb.
This board is basically Peter’s posted circuit, with some extra connections for alternative power. The pre-amp can be used portable with the 9V battery or hard wired in a remote installation. The balanced audio output is via an RJ54 connector for a cat5 run to your sound card.
This is only offered as a partial kit that includes these parts:
Preamp PCB
LMP7721 OpAmp
1G ohm resistor
neon bulb
600:600 ohm transformer
RJ45 female pcb connector
9V pcb battery clips
1×3 SIP
1×5 SIP
SIP jumper (Berg connector)
All the other components are common parts and may be already in your inventory, or readily available from your suppliers.
Click here for the assembly manual
