RommudohMar 12, 2024

Today's #soldering progress on my single buss 1V/oct keyboard, the controller part. Only missing the electrolytic and poly capacitors, some wiring and connectors.

Schematics from #MFOS:
https://musicfromouterspace.com/analogsynth_new/SINGLEBUSSKEYBOARD2007/SINGLEBUSSKEYBOARD2007.php

I did the key part for one octave previously, and modified the schematic for the parts I have available. The key part will be chainable, so I can add more octaves if everything works fine.

#perfboard #diysynth

Show threadRommudohMar 14, 2024
More #soldering done. All components are placed now, only have to do a few connections and jumper wires. I really notice how I'm improving.
Also, the return of the dancing #transistors, this time two #JFET.
#diysynth #perfboard #dancingtransistors
Show threadRommudoh
Finished #soldering the #perfboard yesterday. Sadly, it didn't work as intended. Now comes the fun part — analyzing and fault finding. Already fixed one of the issues by replacing a #capacitor with a bigger one. Now the trigger and gate are generated correctly, but the output buffer for them are constantly high. The sample and hold for the CV outputs worked from the beginning.
#diysynth #keyboard #OpAmps
Mar 16, 2024 at 5:20pmWeb
Show threadRommudohMar 16, 2024
I found the culprit... It's the #TL072 that goes into phase reversal because the gate and trigger signals are -12V when low.
After swapping it with a #LM358, the output signals for trigger and gate, including the LEDs work as intended.
This took a lot of time to find out, but I've gained some knowledge now.
#PhaseReversal #OpAmps #BugFixing
Show threadRommudohMar 17, 2024
After fixing it, I decided to test it. It is connected in place of the step sequencer. It seems to have a small issue with triggering, sometimes causing the sample and hold to resample when releasing the key. Have to look into this.
Here is a short demo of me pressing some buttons: https://makertube.net/w/g88KJst76crKDDJeDxx4QN
#diysynth #synthesizer #perfboard
Demo of my Keyboard input

PeerTube