yes! it irratates me when people say "every thing that can be invented hes been invented." however mealy mouthed they are about it. to make a magamp oscillator you will need;
1) a meadium resister
2) enough suitable wire to wind 3 equal coils
3) (1 bitt core ) 1 torroidal core and 1 broken torroidal core, that can be glued on to the side of the compleat torroid to make a bitorroidal transformer core with air gaps. onto the common leg of the bitt core wind the main coil, conect one end the the battery the other end becomes the ac out put on a dc bias. the second coil is wound on the main torroid, so as to oppose the direction of the magnetic flux from the main coil, when it is conected via the resister to the lead from the battery. the third (comtrole) coil is wound onto the air gapped leg of the bitt core. it is in series with the second coil and is wound so as to further desaturate the core through the main coil. and conected back to the opposit side of the battery. electricaly that is; battery, main coil, the ac outout is between the end of that coil and the battery. battery, resister, second coil, third coil, battery. the action the power is switched on, the flux in the torroidal side of the bitt gose towards saturation. the transformer action between the main coil and coil 2 stops any corrent flowing through the resister, or that circuit. the core saturates, there is no more transformer action, the curent flows through coils 2 and 3 starting to desaturate the core. increasing the resistance in the main coil. by transformer action the falling curent in the main coil increases the current in coils 2 and 3, driving the core towards saturation in the revers direction. the core saturates and the dc curent from the battery through the main coil becomes dominant and the cycle repeats. this might be useful for thing like electric car in hot climbets.