You might think that we enter the cyber world now, and maybe you are right. Old tubes combined with modern dreams, what's wrong with that? Because I can not discuss everything in this project, for this moment I will stay down to earth and focus on what has happened in the twenty amplifiers of the projects 13 to 26. All these amps use the same output transformer GIT80 and power transformer POW80 (see projects 8 and 9). Even the schematics of the amplifier did not change (see project 10). Only the wiring changed and twenty totally different amplifiers were the net result.
I would like to focus now on the systematic approach that I used to design these amps. I already discussed this in projects 6 and 7, but now I need those choices again. Therefore you find below the different options with a systematic number.

Each amplifier of the project employs a selection of the choices available. To make clear what happened, I designed a Matrix which shows how each amps (vertical) uses the possibilities of my universal approach (horizontal). The vertical column 4d is added and means positive feedback at the screen grid (see the Super Pentode amplifier 13). In the lowest horizontal row, ST means the so called "Super Triode" modification, as discussed on my website at DIY-kits. Its easy to implement this special modification into the Project Amplifier, and you can use exactly the same components as applied in my UL40-S2 DIY-kit.

Looking at this matrix, it becomes very clear that several combinations of options are still unused. This really is a challenge. Have my brains been working hard enough or did I forget new possibilities? It even might be so that the white fields in this Matrix contain a fantastic new invention, never heard about, forgotten or not seen by everybody in the tube-world? I would like to focus on that in the next issue of the project.

Next time: The Challenge.