While switching between two FX loops was now theoretically possible, a DRY/WET control still needed to be implemented. My supervisor suggested using the schematics of a splitter and a mixer found on the Internet. As the name already suggests, the splitter splits the incoming guitar signal into two separate signals. These signals each have their own FX loop and go through different effects. Then, they are reconciled in the mixer, where the DRY/WET ratio of the two signals is set and they are both unified into one signal that is then sent on to the amp. The unfortunate part was that by using this method, no bypass switch using relay, MOSFET or Darlington transistor was necessary anymore. Nevertheless, important things have been learnt and the research and tests than were not completely for nothing.
Having never worked with schematics before, basic knowledge about reading and understanding schematics and the components involved had to be acquired. Then, it was decided to start of with the splitter and the necessary parts were bought at Neuhold. Luckily, a sound designer colleague could help me out with a 1uf Elko transistor which was not available at Neuhold. With all parts gathered, it was tried to assemble the circuit. The circuit was assembled on a breadboard. The advantage here is that the parts are not soldered and, thus, fixed in their position. Consequently, mistakes can be more easily remedied. Following the instructions, the circuit was built. To great surprise, it seemed to work. The circuit was tested using two guitar amps and a guitar. The signal of the guitar could be split up to go into both amps at the same time. Thus, the test was deemed successful. However, the two split-up signals appeared to be weaker than the one signal. According to my supervisor, this could be because of the use of different transistors than recommended in the schematic. It will be tried to acquire the correct transistors in order to remedy this problem.
With the splitter working, the mixer had to be built. The mixer posed a greater challenge. Fortunately, my supervisor provided me with the parts necessary. The building of the circuit, however, proved to be quite complicated. The schematic was firstly recreated in the DIY layout creator that lets you create circuits in a graphical way. With the circuit drawn like that, the actual circuit was built on a breadboard. It was testes by plugging in two guitars at the inputs and the output was plugged into an amp. The test was successful: Both guitar signals went through the circuit and into the amp. Furthermore, their individual volume levels could be adjusted using the potentiometers at the input. Nevertheless, I am not entirely sure that everything was done correctly – it just seems too good to be true.
Unfortunately, both parts, splitter and mixer, could not be tested in conjuncture due to the lack of two (!) crocodile clamps that are used to connect the audio jacks to their inputs and outputs. Thus, I cannot simulate the whole signal flow and experiment with the two FX loops yet. However, I have decided to solder cables to the remaining audio jack to be able to test my setup.