The following section will cover documentation and related information on experimental efforts, concerning the development of an ultra low frequency vacuum tube amplifier, intended for Electrodynamic Seismic Forecasting and audio use. Such an amplifier greatly differs from conventional units, as its electrical configuration takes on a similarity to that of the common cathode follower, with addition of improvement as a power gain amplifier.
The first schematic portrayal of the ULF amplifier may be seen below.
As seen above, a simplistic experimental design is presented, whereby the use of two 5687 double-triode vacuum tubes are employed for amplification.
Above, the finished amplifier unit (second panel down) works in tandem with a single pair of Western Electric style repeating coils, for experimental use (first top panel). This photo shows the application of the ULF amplifier as intended for Electrodynamic Seismic Forecasting use, possessing the ability to operate with other instruments as mounted on the rack.
The seismic rack(s) assembly as it currently stands as of September 2023. Note, the amplifier and repeating coil panels mounted near the top right of the photo.
A front view of the amplifier panel may be shown with its indicator lamps and control switches. It must be borne in mind that this unit, as well as the repeating coil panel are highly tentative in electrical and physical construct.
The back of the amplifier, showing experimental output and input plug-in terminals for easy access.
The repeating coil panel possessing the vertically mounted pair of coils.
The back of the repeating coil panel, also possessing experimental plug-in style binding posts.