I love you,zynthian!I believe that when science and art collide the moment will produce the most gorgeous fireworks in the world!

The first handmade synthesizer in my life. :smiling_face_with_three_hearts:Thanks to zynthian platform!In the process of building zynthian, I learned a lot of knowledge about designing hardware and using softwares in my school life.I’m very happy that I have no need to buy a costly synthesizer from Yamaha or Roland and so on … :smiling_face_with_three_hearts: Now I can use zynthian on the stage and in my room ,the ultra low noise and smooth sound waves :laughing:,very nice !I love zynthian !Any open source contributor is great!
Sound card:PCM5122+1863
Zynaptic:74HC14+MCP23017,74HC14 can make encoder signal more stable.
Screen: MIPI
Power:buck module convert 12v to5v for raspberry ,7805 for soundcard (I think a common mode choke is necessary to use.)
PreAMP: Using JRC4580 OP amp to amplify moving coil MIC signal and the other one to amplify the signal from DAC to Headphone.
At present ,the most serious problem is temperature .Because of the small case,temperature always rise to 70 C when power on for 30 minutes.I want to use sheet copper to dissipate heat in next step.


I imagine the two rotary knobs on the top left are for adjusting amp stage gains. ?

Also, it looks like you have a board for feeding an opamp with V+ and V-. What is this ?

Congratulations for your excelent work! You got a nice and very functional unit, @omap7.

I have tested trigger smith gates for debouncing several times (some time ago, when i started the project and recently for a newer prototype we are working on). I’ve measured the bouncing and compared with the simpler capacitor-to-ground solution we currently use. Sincerely, i couln’t find a big difference.

Of course, i understand the theory and i know trigger smith gates are the “killer” solution for debouncing, but in our very concrete real life case, the capacitor-to-ground is good enough if you choose the right values for every device. In our case:

  • 10nF for encoder pins (PEC11 rotary encoder)
  • 100nF for switches (PEC11’s switch)

and it’s a lot simpler :wink:

All the best!

Two konbs,one for adjust the Line out Level and Headphones Level,another one for preAMP Level,especially for external signal input .About power source,I use single power supply,just use two same resistors in series to divide Vcc simply.Look at my circuit! :grinning:(“SR1”&“SR2” are potentiometers).
P1:MIC amp ;P2: Headphone amp

Maybe the parameter of the capacitor was wrong ,The value of 4 konbs always jitter when I spin the encoders. eg:when I spin the encoder first time ,the value=101,nxet step =102,next step =101…Loop :sob:I will try changing more larger capacitor next time.