Introduction

Thank you very much for purchasing one of our DIY kits.

This manual is aimed at guiding you step by step through the process of assembling an ATOV cLFO. If you have any questions or if you are missing a part please contact us at info@atov.de.

Required tools and materials

First, to successfully build this DIY kit, you will need a few tools and materials.

• Soldering Iron
  • No need for a high-end iron. Temperature control is preferable to avoid burning the flux in your solder and leaving residues. With prolonged use, higher than necessary temperatures will damage your soldering iron tip. We recommend the TS-100 or TS-80 digital soldering irons for hobbyist use. As professional tools we use the JBC CD-2BQF with a range of tips.
• Solder
  • We recommend lead-free solder as it is gentler on the environment and your health.
  • We have tested a lot of solder over the years and we now recommend the Stannol Kristall 611 TSC - Sn96.5Ag3Cu0.5. For a good all-rounder we would recommend 0.7mm diameter solder. This is a truly no-clean solder; leaving very little residue, a great finish and with odourless flux fumes. (They do not sponsor us — we just very much like their product and use them in our production line. Bonus: their customer service is great!)
• Side cutter
  • We like flush cutters but side cutters will also work. Any cheap cutters will do but higher quality tools will last longer. Knipex is our go-to in the workshop.
• Multimeter
  • This is important to have for testing and troubleshooting. Use a multimeter with continuity mode. Our reliable and inexpensive recommendation is the ANENG AN8009. If you are in the market for a professional tool, we use the Brymen BM867s (or BM869s if you need temperature probing).
• Flux (optional but recommended)
  • Liquid no-clean flux is sufficient for such a build. In our workshop we use the Stannol 32-10/i no-clean flux pen.
• Oscilloscope (optional, could be a good investment if you want to get serious into electronics)
  • We use the Siglent SDS1104X-E which has been fulfilling our needs until now. Unfortunately we don't have experience with cheaper oscilloscopes. We would recommend getting a digital one instead of analog as they have measuring tools, memory, take snapshots, can decode digital signals, etc. Good oscilloscopes are expensive and this one is a great budget option.

Secondly, to build this kit you need to know how to solder. If you want to learn, our recommendation is to purchase an inexpensive DIY kit from your local electronics shop. This will allow you to train yourself at soldering and build confidence before building a more complex kit.

If you need a small refresh on soldering techniques, here is a tutorial: https://www.youtube.com/watch?v=Qps9woUGkvI

Opening the kit

The kit should contain:

• 1 x panel
• 1 x PCB populated with SMD components
• 1 x bag of parts
• 2 x knobs
• 1 x Eurorack power cable

Open the bag cLFO Parts. Make sure this bag contains the following:

• 2 x potentiometer + nuts
• 1 x tall trimmer
• 11 x jacks + nuts
• 6 x LEDs
• 1 x 2*5 pin header

Check if the kit is complete as well as the state of the provided parts. We inspect everything in the workshop but it's possible that damage occurs during shipping. If there are any obvious defects on any of the parts provided please contact us — we will provide a replacement.

Part 1 - Back Side

There is only one part to solder on the back of the PCB: the 2*5 pin header used as a Eurorack power connector.

Put the connector in its location and solder one pin. We recommend soldering a pin in a corner of the connector. The central pins are connected to ground and because of the internal ground plane take more heat to solder.

When this is done, check if the connector is flush against the PCB. If not, reheat the pin you previously soldered and push the connector down with your finger. Remove the iron and let the solder resolidify.

When everything looks good, proceed to solder the rest of the pins.

Part 2 - Front Side

Start by placing the small circular sticker on the capacitor that will be under the second potentiometer.

Then place the 2 potentiometers and the tall trimmer (potentiometer with black plastic shaft). These are "snap in" — they will snap in place and hold on the PCB. Make sure they are pushed all the way against the PCB. Once done, you can proceed to place the 11 jacks.

Then place the LEDs.

Important note regarding the LEDs in PCB version 1.0:

• The top two LEDs should be inserted according to the silkscreen (long leg on +). However, there is a silkscreen error on the other 4 LEDs and the polarity should be inverted (short leg on +).
• The bottom two LEDs next to the output jack of the ring modulator are very close to each other and are difficult to put through the panel. The solution is to insert them into the PCB and then twist them slightly as shown in the pictures.

Place the front panel and use a nut on one of the potentiometers to secure it in place. Then place some tape over the LED holes (painter's tape works great as it is designed not to leave residue). Push the LEDs into their holes and against the tape to hold them in place.

Then flip the module around and solder the components.

Testing

This module doesn't require calibration, so you can proceed directly to the testing phase.

1. Powering On and Initial Setup:
Turn on the module and adjust the CV2 attenuator to its minimum setting.

2. LEDs and Frequency Adjustment:
Observe that the LEDs illuminate. By adjusting the FREQ potentiometer, you can increase or decrease the frequency of the corresponding LFO.

3. Modulating the Second LFO:
Increasing the CV2 attenuator will result in the second LFO's frequency being modulated by the triangle waveform of the first LFO.

4. Inputting Control Voltage:
Introducing a CV into the CV1 input should alter the frequency of LFO1.

5. Testing Waveform Outputs:
Test all the waveform outputs by routing them to a parameter you wish to modulate. Using VCO frequency control inputs can yield clearly noticeable results. Ensure each waveform transmits the anticipated signal.

6. Examining the Ring Modulator's Output:
Connect the X*Y output from the ring modulator to a VCO's frequency control input and verify it behaves as expected.

Any issues? Contact us at support@atov.de

Part 4 - Final Assembly

When everything works well, you can finally install the remaining jack and pot nuts. Put the push-on knobs onto the potentiometers.

Congratulations! Your ATOV cLFO is now complete and fully functional!