Here’s my latest dual 1K80H amplifier, mostly in pictures.
Last year I decided I would design and build a regulated temperature-compensated independently adjustable dual bias circuit for my 2x LDMOS amp. (what a mouthful) Why? Because I wanted to try an experiment which actually works in a class AB … [Continue reading] about Single versus Dual Bias for LDMOS RF Amps
So I've gone around the block on this one. Tried a bunch of designs, studied a bunch of others and finally designed my own! The goals of the bias circuit include: Present a well regulated, extremely clean DC bias to the gatesAllow for a very … [Continue reading] about Biasing Schemes Revisited
Jerry Sevick, W2FMI (SK) called this the "Soak Test." He used it to run real power through the TLT network to check efficiency. It's a pretty simple test whereby you simply run significant power through the TLTs and measure the temperature … [Continue reading] about Transmission Line Transformer Testing
There's a quite famous audio amplifier builder (legendary really) named Nelson Pass that makes very high end audio amplifiers. In some of his amps, he even goes so far as to allow you to manually skew the bias via a knob on the front, so you can … [Continue reading] about Nulling the Even Harmonics