Hi all!
I’m new to this and have recently finished building the cem3340 vco and fc power psu.
There’s no sound coming from the vco and someone on reddit said that I might need a driver to hear it, is that true? I haven’t seen anything about it so I don’t know what to believe.
Also, how do I make sure everything works? I have a multimeter but doesn’t really know how to use it.
What did you hook the VCO up to?
First just a speaker, then an amplifier before speakers. I did some googling, did the redditor mean that I need a vca to hear anything?
You might want to read this:
A vco is not meant to be connected to a speaker directly. Depending on the impedance of the speaker you may hear something if that impedance is high, but that is not the case with modern speakers. You may need to set a frequency and get the VCO to trigger. But most likely it is free running, so it should always produce some signal.
Yes, a VCA would mute it receives a control voltage as well. Without VCA, it should always make a sound.
I will check out the troubleshooting guide.
But how am I supposed to patch it? So I do need some sort of driver? I am so confused right know, why isn’t this mentioned somewhere, or is it? Thanks for the help.
You don’t need anything but the VCO itself (and the power supply of course). You then plug it into an amp, a mixer, a sound card, a powered speaker or something like that. Perhaps you can post pictures of your build? Which schematic did you use?
Where did you acquire your TL072?
Also looks like this could be the end of my reign as the only Kosmo in Scandinavia…
@Veticus is from Denmark, for certain values of Scandanavia.
So am I! I just don’t live there anymore 
Yeah, I don’t immediately see anything off in your build. I recommend the troubleshooting guide as well.
I bought it from electrokit.com.
I sure hope so, haha!
Maybe check and remake some solder point, and the possibility of shorts, like here
you can pass a knife/cutter blade between the lines, then a little brush stroke, to be sure, because sometimes it’s not visible to the naked eye (some here have had this experience 
)
You’re a wizard Harry! It’s working now! Really impressed that you found that, haha. Could barely find it even with the picture. Thank you so so much!
Abracadabra !!!
To quickly clean between the lines, I do it at the end of each stripboard soldering, and it avoids this kind of problem, glad it works !
Are the 10uf capacitors in the dual Vca polarized? I didn’t notice the - on the picture until I was building, I bought bipolar ones. 
Hello, I think you are the person who wrote me an email about the dual VCA I have answered you.
but you’re not in the good thread
maybe here
Yes, haha, I’m inpatient thank you so mich
