hello this is usually not there as it will vary from where you source the components. init could cost for all the components anywhere from £20to £40 depending where you look to get the items, usually people who decide to jump into this diy stuff tend to buy more resistors for instance than they need which in the longterm dramatically reduces the price.
with this project there are 2 expensive parts thats the CEM chip could cost anywhere between £4 and £10, and an Arduino Copies can cost £1.50 and proper ones can cost £20. then there are potentiometers you need 4 so that would cost about £5, jack sockets about £4 then the rest of the components depending where you get them could range from anything between £5 and £15-£20
its also not included as each country has different preferred stockists, there is a thread somewhere on the forum called cheap component search find that it usually really helps in this case.
My 1222 VCO smoked out yesterday. Both ferrite beads and the 10uf blew up. I replaced the 10uf with a 250v and replaced the beads with 10 ohm resisters and the resisters smoked out again. I reflowed all the solder twice on all power components but 3rd time was not charming at all, any suggestions?
It’s always important to try common troubleshooting steps first, even if it seems trite.
Anyways, this really feels like a backwards power cable or something. Anything change about the module or your power situation? Did you move the module recently?
Ive got funky issues with mine, i built 3 all at the same time and 2 have a similar issue just in different extremities. Ive set the 4volt reference correctly and matched the resistors to ensure its 1volt per octave however it still doesn’t stay in tune when switching, ill tune it to A4 for instance at the highest octave and in the lowest it will go to something around B#. 1 works perfectly and the other two just seem to have a mind of their own.
Ive gone through all the basic trouble shooting methods to no avail and i dont know too much about electronics so im not sure where to start my trouble shooting.
Im using the CEM3340 chip with the 10k resistor it asks for that buts as far as it goes with my knowledge for electronics. Even after leaving them for 45mins before all the tuning the issues still persist.
Any help would be cooooooooool thaaaaanks
EDIT- So i fixed it haha…the connector for the octave knob must have had a bad crimp or something. Soldering the wires directly fixed it i think…just letting them warm up
Hey, I have just built the FC power and I’m about to build my first VCO, I am going to build the 3340 chip based one by LMNC and I’m going to make it on strip board (see layout attached) however I want to add the octave selector like the one on the 1222 PCB layout he sells. I have seen a bunch of posts about it however it doesn’t make much sense to me, has anyone done this already?
I am very new to this so any help would mean a lot and I just want to figure this out before I build it .
Hi, as it is your first VCO project (and from a personnal point ot view), I would not recommend adding the octave switch but I would 100% add a fine tune knob (I didn’t put one on mine and I regret it a lot).
On the schematic (STUFF - LOOK MUM NO COMPUTER), the octave switch needs the REF voltage ( using the 100K trimpot and the LM4040AIZ 4.1) and therefore you need to add a fair amount on top of the simple VCO schematic.
So, to my opinion, it is more challenging if you do it yourself yes. You can also get the PCB from the online store, I guess. But, hey, the beauty of DIY is to do what we want and not only what is available. If you do decide to start with this, you will probably learn a lot from your first module.
The voltage reference and associated trimmer and resistor aren’t hard to add to the stripboard if there are about four strips available, and the resistors for the rotary switch can be mounted on the switch itself. The problem is you need an op amp. So you’d either have to add another IC to the layout, or replace one of the TL072s with a TL074 and revise the layout accordingly.
You could build the VCO without the octave switch and add it later. Easiest thing then might be to make a little separate stripboard with the IC and resistor and trimmer and voltage reference on it, and wire ±12 V and ground and the switch output between the two boards.
an anyone help with trouble shooting? I’m building 3 of these and just finished the first one. When I powered it up nothing happened although I think the arduino light might have blinked once or twice. I’ve gone back to absolute basics ,checked the power supply. I’m getting -12/0/+12 at the power supply but when I read the pins on the module (using dupont wires to connect up one each of -12/0/+12 and probing the other) I see small voltages on the pins and both are -Ve. I understand that there should be current draw from later in the circuit but was expecting the voltage drop over the input pin with respect to ground to be +/- 12V.
I’m still pretty new to this although I’m happy with most of my soldering
You mean you’re connecting the voltmeter from one +12 V (or -12 V) pin to another? Or from +12 V (or -12 V) to ground? Should be the latter.
If you measured from ±12 V to ground and got something much smaller than ±12 V there’s definitely something wrong, don’t re-connect power until you’ve figured out what. See
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