antique 1920s Crystal Radio w 4000 Ohm Telefunken Headphones Awesome Ebonite Top ^Sale

Unbranded crystal radio comes from estate of radio enthusiast.
it is only 15*11*9,5 cm: What's inside - these have coils wound with extremely fine wire on iron cores.
Includes E.H.333 headphones of 4000 ohm resistance: These vintage headphones designed to be driven by crystal radios or a simple tube stage. They use vanishingly small current levels and, in some sets you can hear buzzing in the headphones by gripping the plugs with your fingers. The DC resistance is 4000 ohms, meaning the impedance is actually much higher. Magnets installed inside the cups make a net magnetic field involving the coil, the cup itself, and a diaphragm made of thin steel. There's a gap between the steel diaphragm and the iron cored coil that might be 2-4 times the thickness of the steel itself. When AC comes in contact with the coil, it forces the steel back and forth to create sound.
The weight is 0,7kg in total.