Troubleshooting Steiner VCF
2010-02-04 by regrehan
Just joined this group. Kudos to Ken Stone for the website and all the information.
My son is a senior in high school, and is in the process of building a small music synthesizer as part of his computers and electronics class. He has already built a couple of the 4069-based VCOs from Rene Schmitz's site, and they're working pretty good.
He has also built a Steiner LP BP HP filter using the schematic at the CGS site. It's not behaving well. Does anyone have any troubleshooting tips for this circuit -- something along the lines of "If you put a 1kHz square wave into the BP input, you should see X at the anode end of the diode string, and Y at the cathode end." (We have a 'scope.) Or "with no signal at any of the audio inputs. the voltage on the + side of the 1uf capacitor of the LP in should vary from x to y as you adjust the CV frequency pot from 0 to +15V." Stuff like that that could help us home in on the faulty section.
Maybe this has been dealt with elsewhere. If so, my apologies for repeating such a request (and if someone could point me where, that would be great). I'll dig around the message board and see if I can find anything that might help.
Thx.
My son is a senior in high school, and is in the process of building a small music synthesizer as part of his computers and electronics class. He has already built a couple of the 4069-based VCOs from Rene Schmitz's site, and they're working pretty good.
He has also built a Steiner LP BP HP filter using the schematic at the CGS site. It's not behaving well. Does anyone have any troubleshooting tips for this circuit -- something along the lines of "If you put a 1kHz square wave into the BP input, you should see X at the anode end of the diode string, and Y at the cathode end." (We have a 'scope.) Or "with no signal at any of the audio inputs. the voltage on the + side of the 1uf capacitor of the LP in should vary from x to y as you adjust the CV frequency pot from 0 to +15V." Stuff like that that could help us home in on the faulty section.
Maybe this has been dealt with elsewhere. If so, my apologies for repeating such a request (and if someone could point me where, that would be great). I'll dig around the message board and see if I can find anything that might help.
Thx.