Don’t you love it when a plan comes together? Well, if you are going to copy the work of a master, you cannot go past copying the work of Wez Hayward. Having built this amp design before on some copper board with through hole parts and done a whole lot of measurements on it, I knew that it was a design that was not going to disappoint. What I was not ready for though, was just how much better it is when using somewhat better design principles, SMD parts and an average PCB layout.
Just how good is it? Well, flat gain from 1Mhz to 50Mhz, without using any fancy transistors, just plain old vanilla popcorn 2n3904’s.
The dip between 5 and 7Mhz is an artifact from the NanoVNA and is not actually there, i looked with the oscilloscope and function generator just to be sure. While the NanoVNA is good, its not perfect, but as AVE likes to tell us, its good enough for the kinds of girls I go out with. The gain, in dB is actually also not right.
The input is 100mV and the output is 1V, by my math that is 20dB gain, so its exactly as designed. All that is left is to populate the attenuators and I have an variable gain amp to use for testing purposes or a receiver front end, which is the ultimate end use for this.