# 1222 Tuner VCO Module **URL:** \ **Category:** KOSMO MODULES\ **Created:** [January 17, 2020, 5:33pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16 "2020-01-17T17:33:40Z")\ **Posts on this page:** 20\ **Page:** 28
**Author:** ![lookmumnocomputer](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/lookmumnocomputer/32/23_2.png) [@lookmumnocomputer](https://lookmumnocomputer.discourse.group/u/lookmumnocomputer)\ **Post date:** [November 25, 2021, 10:19am UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/545 "2021-11-25T10:19:32Z")
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. ---
**Author:** ![BlackDeath](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/blackdeath/32/7644_2.png) [@BlackDeath](https://lookmumnocomputer.discourse.group/u/BlackDeath)\ **Post date:** [November 25, 2021, 9:14pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/546 "2021-11-25T21:14:49Z")
Pretty! 🙂 🙂 🙂 🙂 🙂 🙂 ---
**Author:** ![JUXTAPOZ74](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/juxtapoz74/32/523_2.png) [@JUXTAPOZ74](https://lookmumnocomputer.discourse.group/u/JUXTAPOZ74)\ **Post date:** [January 5, 2022, 12:28pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/547 "2022-01-05T12:28:48Z")
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? ---
**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\ **Post date:** [January 5, 2022, 12:45pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/548 "2022-01-05T12:45:09Z")
> [@General advice for troubleshooting a module and asking for help](https://lookmumnocomputer.discourse.group/t/general-advice-for-troubleshooting-a-module-and-asking-for-help/2049): > > (This is a wiki post, please add and correct!) Look and see if others have had the same problem. Use the Discourse search facility to find topics where the module you’re building is discussed. Inspect your work. Verify all components are correct values. Look for solder connections that are rough, irregular, skimpy, dull, or missed completely (we all do that!) and reflow them. Look for solder bridges between pads and remove them. Check your power connection. If it’s a Eurorack style power cabl… ---
**Author:** ![JUXTAPOZ74](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/juxtapoz74/32/523_2.png) [@JUXTAPOZ74](https://lookmumnocomputer.discourse.group/u/JUXTAPOZ74)\ **Post date:** [January 5, 2022, 2:09pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/549 "2022-01-05T14:09:17Z")
Yes I’ve read it, thanks. ---
**Author:** ![Caustic](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/caustic/32/15588_2.png) [@Caustic](https://lookmumnocomputer.discourse.group/u/Caustic)\ **Post date:** [January 5, 2022, 3:00pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/550 "2022-01-05T15:00:08Z")
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? ---
**Author:** ![JUXTAPOZ74](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/juxtapoz74/32/523_2.png) [@JUXTAPOZ74](https://lookmumnocomputer.discourse.group/u/JUXTAPOZ74)\ **Post date:** [January 5, 2022, 6:07pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/551 "2022-01-05T18:07:42Z")
It’s not trite, I get it, I’ve read it. ---
**Author:** ![TylerTheFolf](https://avatars.discourse-cdn.com/v4/letter/t/c5a1d2/32.png) [@TylerTheFolf](https://lookmumnocomputer.discourse.group/u/TylerTheFolf)\ **Post date:** [January 7, 2022, 8:21am UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/552 "2022-01-07T08:21:20Z")
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 ---
**Author:** ![JackLovell](https://avatars.discourse-cdn.com/v4/letter/j/85f322/32.png) [@JackLovell](https://lookmumnocomputer.discourse.group/u/JackLovell)\ **Post date:** [February 21, 2022, 9:53am UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/554 "2022-02-21T09:53:58Z")
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 🙂. Layout I’m using: ![InkedCEM+3340+PWMFIXED_LI](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/7/7/77d74be876e100b8128e9775cad5a68e8073f20d.jpeg) ---
**Author:** ![Bpbby](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/bpbby/32/15259_2.png) [@Bpbby](https://lookmumnocomputer.discourse.group/u/Bpbby)\ **Post date:** [February 21, 2022, 10:05am UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/555 "2022-02-21T10:05:22Z")
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). > [@LMNC Simple VCO with Fine tune issue](https://lookmumnocomputer.discourse.group/t/lmnc-simple-vco-with-fine-tune-issue/3247/2): > > Welcome in the forum, If it’s tune without fine tune, add just this resistor and pot for fine tune, it work fine for me slight_smile ---
**Author:** ![JackLovell](https://avatars.discourse-cdn.com/v4/letter/j/85f322/32.png) [@JackLovell](https://lookmumnocomputer.discourse.group/u/JackLovell)\ **Post date:** [February 21, 2022, 10:17am UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/556 "2022-02-21T10:17:16Z")
I kind of want both, Is the octave switch hard to add? ---
**Author:** ![Bpbby](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/bpbby/32/15259_2.png) [@Bpbby](https://lookmumnocomputer.discourse.group/u/Bpbby)\ **Post date:** [February 21, 2022, 10:26am UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/557 "2022-02-21T10:26:49Z")
On the schematic ([STUFF - LOOK MUM NO COMPUTER](https://www.lookmumnocomputer.com/1222-performance-vco)), 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. 😉 ---
**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\ **Post date:** [February 21, 2022, 1:09pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/558 "2022-02-21T13:09:09Z")
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. > [@Bpbby](#): > > (I didn’t put one on mine and I regret it a lot) That’s even easier to add! ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [February 21, 2022, 1:54pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/559 "2022-02-21T13:54:16Z")
I’ve done it on several of my VCO, here’s the schematic part to add the octave switch selecter > [@3340 VCO Schematic for PCB design](https://lookmumnocomputer.discourse.group/t/3340-vco-schematic-for-pcb-design/730/43): > > Personally I would also suggest adding the octave selection, really very practical On my VCOs that don’t have it I miss it a lot R42 must be changed, i don’t remember exactely maybe 2K (i ll searched and come back slight_smile ) EDIT : I found it, between 1K and 4.7K (By the way, R42 shown there is specified as 220 ohms but it really should be higher; 220R results in too much current through the voltage reference U4, potentially causing bad behavior and possi… ---
**Author:** ![heckseven](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/heckseven/32/23483_2.png) [@heckseven](https://lookmumnocomputer.discourse.group/u/heckseven)\ **Post date:** [February 22, 2022, 11:50pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/560 "2022-02-22T23:50:32Z")
How easy would it be to mod one of these to be able to tune other oscillators? ---
**Author:** ![devicex](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/devicex/32/28_2.png) [@devicex](https://lookmumnocomputer.discourse.group/u/devicex)\ **Post date:** [February 23, 2022, 12:00am UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/561 "2022-02-23T00:00:10Z")
> **[CalTrans Calibrator + Transposer](https://www.perfectcircuit.com/klavis-caltrans.html)** > > The Klavis CalTrans is a quad calibration and transposition module useful for streamlining some of the difficulties that occur when introducing tonal harmony to modular synthesizers. you mean one of these ? yeah diy would be cheaper . ---
**Author:** ![ChristianBloch](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/christianbloch/32/56_2.png) [@ChristianBloch](https://lookmumnocomputer.discourse.group/u/ChristianBloch)\ **Post date:** [February 23, 2022, 1:06am UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/562 "2022-02-23T01:06:15Z")
You’d at least have to cut a trace since it’s already always listening to the ramp output of the 3340. That does sound like a neat feature, though. ---
**Author:** ![BoneMusic](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/bonemusic/32/23323_2.png) [@BoneMusic](https://lookmumnocomputer.discourse.group/u/BoneMusic)\ **Post date:** [March 9, 2022, 4:31pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/563 "2022-03-09T16:31:44Z")
Hello! 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 ![IMG_20220309_162120](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/f/f/ffe4454e992be53bfe0555afbda032997e1f7c89.jpeg) ![IMG_20220309_162149](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/9/1/9163bcb1e28a78d1b11bdbd2d7cb6cf1842d2826.jpeg) ---
**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\ **Post date:** [March 9, 2022, 4:46pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/564 "2022-03-09T16:46:03Z")
> [@BoneMusic](#): > > when I read the pins on the module (using dupont wires to connect up one each of -12/0/+12 and probing the other) 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 > [@General advice for troubleshooting a module and asking for help](https://lookmumnocomputer.discourse.group/t/general-advice-for-troubleshooting-a-module-and-asking-for-help/2049): > > (This is a wiki post, please add and correct!) Look and see if others have had the same problem. Use the Discourse search facility to find topics where the module you’re building is discussed. Inspect your work. Verify all components are correct values. Look for solder connections that are rough, irregular, skimpy, dull, or missed completely (we all do that!) and reflow them. Look for solder bridges between pads and remove them. Check your power connection. If it’s a Eurorack style power cabl… and > [@Advice for troubleshooting 3340 based VCO](https://lookmumnocomputer.discourse.group/t/advice-for-troubleshooting-3340-based-vco/2077): > > This is a wiki post; please correct and improve! This is written regarding the 1222 Performance Oscillator module, but similar things apply to the simple stripboard oscillator or other oscillators based on the 3340 chip. For the stripboard version also see If you are not getting good tones from the oscillator, do the following. If with the 1222 you are also not getting good behavior from the tuner, don’t waste time on trying to fix that yet. Get good tones on the outputs first — the tuner won… ---
**Author:** ![BoneMusic](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/bonemusic/32/23323_2.png) [@BoneMusic](https://lookmumnocomputer.discourse.group/u/BoneMusic)\ **Post date:** [March 9, 2022, 4:47pm UTC](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/565 "2022-03-09T16:47:47Z")
I’m reading the input voltages relative to ground. Thanks for the links I’ll take a look I’m wondering if it’s the power supply that’s the issue but I’ll have a read through/ [Previous page](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16.md?page=27) [Next page](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16.md?page=29)