B-17B Preamp Construction Begins

It’s finally time to start building a prototype of the B-17B preamp. Being that this is a prototype and we’ll need to be able to easily probe signals and swap components, I decided to build it using just a sheet of aluminum rather than a full enclosure. You’ll see what I mean below. But first here’s the layout:

Drill layout

The five holes along the bottom are for the potentiometers for Treble, Shift, Bass, Gain, and Master controls. The hole in the middle is for the 12AX7 tube socket.

This layout is designed so that it will fit in a 5-inch by 7-inch enclosure eventually. Below you can see the test fit of the components once I drilled the aluminum sheet (this is just stock aluminum that I picked up at the local hardware store).



As you can see this won’t exactly meet UL standards, but it should work well for our prototype. Next step is to wait for the power transformer to arrive (due Wednesday) so I can drill those mounting holes before starting to add the components. But meanwhile there’s time to add a little NSE yellow…


I also picked up another project yesterday that I hope to dig into today. It’s a 1946 Hallicrafters S-40 shortwave radio. So far the only sound it makes is buzzzzzzzzz….