tisdag 29 september 2009

tisdag 15 september 2009

Construction of a 2xGI7B Power Amplifier


After spending the first 6 month of this year colleting parts it has become time to start the actual building. This is a mockup to decide the size of the cabinet. The tube in the upper right corner is not the 2xGI7B. I'm still waiting for the delivery. I put in the GS35B since the mockup looked empty without a tube. The transformer delivers 900 volts at 0.8 ampere ICAS, which I calculate will be enough to drive the amplifier to 1 kw in SSB service. With a voltage doubler the DC ouput will be around 2500 volts. The transformer was ordered from a factory in Czech Republic. The plate capacitor measures 22-320 pF and is also specially made for this project. It was orderd from Ham Center in Italy. The tune capacitor is a 1000 pF surplus capacitor. Maybe it is a little bit too big physically. I might find a smaller one for the final design. The next step is to etch the voltage doubler board and assemble the G3SEK Triode Board