MP-02 style plasmatweeter
My old dream...
It was 1993 when I the first time decided to build a Magnat MP-02 like tweeter. I don't want to spend over 2000.- DM (EUR came years later) for a pair of original Magnat. I thougt it could not be that difficult. The RF Transistor was expensive too but I had a big collection of tubes. I decided to use a beam power tube EL519 for the self oscillating device. My first plasma tweeter was born and I had a lot of fun matching it with different type of speakes.
I shared it with the DIY community on my old site "www.plasmatweeter.de" in the hope that there are other enthuisiasts out there to improve the circuit. After 25 years now I can say this did not really happened, maybe but I don't know about. My old circuit plan is circulating all over the world mostly unchanged.
A while later I make a new circuit for the modulation with a transistor. This version was often copied and some guy's improved it with more modern FET devices.
Picture of my old design back in the 1990's
Th. Riethmüller hat 2006 freundlicherweise eine Baumappe für den alten PLasmatweeter mit Röhren erstellt, so bleiben diese Information erhalten, Danke !
Let's start
Time to make a new one ! Now with transistors. Today they are not expensive and easy to get. One thing I want to mention. Most of the cheap chinese transistors are bad quality. Especially RF transistors. I struggle with this often in my old job. I have a bunch of 2SC1306 and PT 9783, which were used in the MP-02, out of chinese production thrown in the trash because they dont work properly in the circuit. Therefore I always try to use NOS (new old stock) examples.
Schematic
To start we are using the original Magnat schematic. The circuit is easy to explain. T1 is the oscillation circuit with a crystal locked to 27.125Mhz. T2 is driver and T3 is the RF power amplifier. A simple amplitude modulated transmitter in the CB band with approximately 50W of output power. In the upper section wie have the active crossover with IC1a and IC1b (TL072 or TL082) and IC2 power amplifier STK086. Thats it !
Update March 2021
I took the PCB's from my Transistor Ionophone and hook up the MP-02 style electrode with ball and.... see Video beside.
more to come ...
The project is on hold for now.
I decided not to make them anymore because of the high amount of Ozone the big flame radiate.
It needs good shielding to keep the ozone in the cage so that it breaks down due to the high temperature. I also don't know the catalytic converter braid that Magnat used.
