Well, got a little more done today..I etched up some simple circuit boards for the Bias cut off and Bias board protection..Also a simple Glitch resistor board that goes into the HT line and a Step Start resistor board..Pics show the finished boards..
I also completed the installation of the Pi output network..It all fits snuggly and is resonant through the band..I am just making the amplifier front panel..This takes time and patience..The layout has to be functional and presentable to look at..Also the top and bottom aluminum trims, 12mm square, has to be attached with a 2mm spacing at the top and bottom to accommodate the flush fitting covers..
I have had a few emails asking how I fit the 12mm aluminum angle..I took a pic of one corner while I was working..In this case the angle has to fit 2mm below the sides of the box so that the top cover is flush when fitted..I pre drill the box then cut the angle to size and using small clamps drill and fasten the angle to the inside..I cut all the angle with a hacksaw in the vice and trim it to an exact fit using a file..Works every time, or nearly..:chin:
BTW the fan is a 240 volt all metal 6 inch Papst rated at 290cfm..I like these particular fans as the metal blades are heavy and don't lose speed under load.. This produces more than enough air to cool this tube even at 1800 watts output..I must measure the back pressure..I have a manometer in a drawer somewhere..
Reply With Quote