This Gema Amplifier is a mystery to me. A friend of mine was able to provide me with the information that this device was part of a underwater acoustics hydrophone that could be lowered from a ship or small boat. Mine is sadly missing the type plate that would have said bya VH4
Here you can see where the type plate would have been and where it would have been connected to the chassis.
Here you can see the inside. The Amplifier uses two RV2p800 Tubes both marked Kriegsmarine and they are the original ones NEVER CHANGED. The construction is of a very high quality and every part is numbered.
This is where the power would have been connected to 120V -1.5V and 2V for the Heater. It is also the signal input and output. Very nicely visible is the ceramic Capacitor.








