Completed the preamp and have it connected to a Q-watt amp for testing  The sound overall is impressive but have one concern and that is the treble adjustment  There is none  Have connect a AC volt meter to the output to monitor amplitude  change while making adjustment to the treble .  Have not seen any change on either channel  Any comments or suggestion would be  Appreciated The bass amplitude voltage change is huge. 

Hallo zusammen! Ich habe mir nun auch das Kit zugelegt und alles installiert. Läuft bis jetzt auch alles prima, allerdings muss ich auch noch ein paar Dinge anschließen und installieren. Miene Frage nun, wie habt ihr die zusätzlichen Sensoren installiert? Bspw. den UV und den Lichtsensor und wo habt ihr, falls installiert, die Feinstaubsensor installiert.

If the I2C interface to the BBAI is not needed the I2C device address jumper can be used for something else, such as to select fan speed.

Hi, I built that preamp and I got on the input of LM837 2MHz sinus. The LT1028 working like oscilator. It doesn't matter if power is coming from battery or transformator. Assuming that missing decoupling capacitors has an impact on oscilation. Looking into supra 2.0 preamp (big schema), every OPA is decoupled and has frequency compensation (https://www.elektormagazine.com/news/cool-summer-free-download-of-the-week-supra-2-0-super-low-noise-mm-md-phono-preamp) Any idea how to remove oscilation? best regards M. Found the problem. The pcb (brg file) has missing path, sum isnot linked with in of lm837

This looks very cool, and I'm going to build one right away. But is it possible to increase the number of inputs?  That is, add an additional analog input and 3 or 4 more digital (switch) inputs? I know I should probably just build a modified version and find out for myself.  But sadly, I'm only a so-so Microchip programmer and know next to nothing about USB (at this level). So if my modded version didn't work, I wouldn't know if it's because I screwed up (the most likely possibility) or because it was never going to work no matter what I did. Any thoughts appreciated. Alan