First I would like to refer prospective Sudden Transceiver builder's to SPRAT 175 (Summer 2018) as there is an article by Nick G8INE with some added words by me. The basic 40 Meter driver circuit that is featured in that SPRAT article you will also find that same pre-driver in the Sudden Transceiver. This circuit has been carefully designed so that the input and output is at 50 Ohms. R3 in the simulation below is only there for the simulation and not installed in the actual circuit

 

 

 

 

With a bit of more history repeating itself, in 2017 I built another 40 Meter SSB transceiver called the Simpleceiver Plus. This transceiver is not unlike the Sudden Transceiver in that an IF Module comprised of a pair of tuned J310 stages similar to above are used ahead and following a 9 MHz filter and the transmit pre-driver which is also relay switched (in/out) serves as the receiver RF amplifier. A total of six J310's is literally the whole transceiver. This too was a single pass relay switched system versus the bilateral architecture.

This project was documented on my blog n6qw.blogspot.com. I cannot overstress the use of LT Spice as a design tool --once you have one variant of a circuit such as the combo J310's you can customize it as a broad band or narrow tuned amplifier. Here is an example of a 9 MHz IF amplifier.