Category: DIY

ST Modular Give II

Troubleshooting the Give II

UPDATE: Found the issue!

I was looking over the BOM and my Mouser order and found that I had a substitution for T1 (MMBFJ309) and what I got had the source and drain pins swapped. I also swapped out IC1 with a new TL072 and the VCO fired right up.

My voltages are a mess! No parts were subbituted and I removed the LED and trimmer. I checked the orientation on all of my ICs and electro-caps.

IC1 (TL072)

  1. -6.3v
  2. -6.3v
  3. 0
  4. -11.3v
  5. 0
  6. 2.3v
  7. -10v
  8. 11.3v

IC2 (TL072)

  1. 4.4v
  2. 0
  3. 0
  4. -11.3v
  5. 2.9v
  6. 5v
  7. -9.3v
  8. 11.3v

IC3 (TL072)

  1. 9.5v
  2. 0
  3. 9.5v
  4. -11.3v
  5. 9.7v
  6. 9.5v
  7. -9.2v
  8. 11.3v

IC4 (TL074)

  1. -3.5v
  2. -0.7v
  3. 0
  4. 11.3v
  5. 0
  6. 0
  7. -7.1v
  8. 4.8v
  9. 0
  10. 0
  11. -11.3v
  12. 0
  13. 0
  14. 0

IC5 (TL074)

  1. 0
  2. 0
  3. 0
  4. 11.3v
  5. 0
  6. 0
  7. 0
  8. 0
  9. 0
  10. 0
  11. -11.3v
  12. 0
  13. 0
  14. 0

U1 (CD4024BM)

  1. 0
  2. 0
  3. 0
  4. 11.3v
  5. 11.3v
  6. 11.3v
  7. 0
  8. 0
  9. 11.3v
  10. 0
  11. 0
  12. 11.3v
  13. 0
  14. 11.3

Nearness Attenuated

Nearness is a simple but effective panning mixer. Seven inputs, two outputs. The closer an input is to an output, the greater its influence on it. This is a remixed version with attenuators on the output so you can adjust the volume of each signal.

Resources:

I got the PCB and panel made from JLCPCB from the gerbers in the Github repository. This was a really easy and straightforward build.

Mutable Instruments Module Tester

I wanted to build one of these when I first started my DIY eurorack adventure but never got around to it. I seen that the hardware got a revision recently and did away with the AC adapter needs and went with a more readily available 15v DC adapter. I had the PCB fabbed from JLCPCB and parts came from Mouser.

This utility is pretty straight forward. The ability to power your module you are troubleshooting off of this tester and to send various control voltages (waveform, LFO,notes,gates,clock) along with feeding audio & gate back into it will help greatly to pinpoint issues.

Resources:

Flashing the AVR was pretty straight forward. Just needed to hook up the AVR ISP XPII, power up the unit and write the HEX file.

I used Ponoko for the first time to get the case laser cut and I think it came out great. I went with black sides and a pink top, cause why not.

Since the laser cut box came flat and had masking tape on it, I was able to spray paint the top black to back fill in all the text and logo. I was amazed how well this worked out.

Done, time to start troubleshooting some of my modules in my “box of fail”

Antumbra Path

I found that I was in need of a sequential switch and really wanted to see what DIY options where out there. The Antumbra Path is a 2 channel 4 in 1 out or 1 in 4 out since its bidirectional. The channels can also be combined to make it 6:1 or 1:6. This makes for some very cool switching options.

I picked up the PCB and panel from Pusherman’s store.

Flashing the ATMEGA328P was easy with the Waveshare AVR ISP XPII and AVRDUDESS software.

This was a very straight forward build and was a nice change from all the huge builds I have been doing lately.

Neutron Dust of Time

I was not in the market for another digital oscillator but when I saw this on Muffwiggler forums I really wanted to build it. This is a dual stereo oscillator with built in modulators and utilities based on a teensy 3.6.

I picked up the PCB and the panel from Michigan Synth Works.
https://michigansynthworks.com/

The build was actually not that hard but just dense with parts. The only really frustrating part was all the parts I kept forgetting to order and having to wait for them.

Block diagram of signal path. Image by Neutron Sound

Testing this dirty PCB before I gave it a good cleaning. This new iPhone camera brings out every piece of dust/hair/flux residue.

ST Modular Pedal Pal

I currently have a Malekko SND/RTN module that I use for all my outboard effects pedals. It’s a great module but I really wanted an easy way to get a stereo signal back into the modular for pedals like Strymon Timeline and BigSky. The ST Modular Pedal Pal seems to scratch that itch with its mono send and stereo return. I think the only upgrade to this would be a full stereo path on the send also, but not sure if it really matters for my use.

I think the added bonus of this is having the CV controllable expression jack with an attenuator. I have hopes to use this with the Strymon BigSky for modulation amount or wet and dry. Just a note that the Pedal Pal supports 3v & 5v expression output voltage. This can be changed by a jumper located on the back of the module. Make sure you look in your pedal manual to see what voltage is needed. All Strymon pedals use 5v on the expression jacks.

I picked up this PCB and panel from Pusherman’s store.

This was a very easy and straightforward build.

DIY Monome TeleType

On Nov 26, 2019 Monome released their TeleType eurorack module to the world under the Creative Commons (cc-by-sa-3.0) to GitHub. They made available the Gerbers and front panel files along with a BOM. I have wanted one of these modules for awhile, but it was hard to take the $500 plunge. It has such a steep learning curve and I was afraid I would not dedicate the time it needs to learn it.

I just happen to check Pusherman’s store out to see what new PCBs he had available since I was itching to build something. To my amazement he was offering the TeleType PCB/Panel under the name “Terminal”.

I quickly made a BOM on Mouser for the needed parts and I quickly noticed this project uses 402 SMD parts.. TINY parts.. The smallest I have done to this date was 603 and even that was a bit nerve wracking. I really wanted to build this thing so I decided to give it a go.

I made an export of the PCB in EagleCAD to help ID the part locations since the PCB silkscreen is hard to decipher at some points.

Click on image for full size
Pusherman PCB & Panel kit called Terminal

Its so weird to be more afraid of all the resistors and capacitors over needing to soldier the AVR.

I mostly got the PCB populated and was waiting for a couple parts that were not in the BOM.

USB Cable:
To flash the AVR it was really easy to use Monome’s instructions with a USB-A to USB-A cable. I did not have a cable and needed to make one. Just cut a couple USB cables you have laying around and match the RED, WHITE, GREEN, BLACK and you will be fine.

Follow the instruction from Monome’s website for firmware flashing

Booted right up

I wanted to test all the LEDs and voltage from all the in/out jack pads before I installed the jacks. Once the jacks are soldered in it will be difficult to troubleshoot the parts between them.

Protip: If you are having issues with the trigger out LEDs, its most likely IC1 or the capacitors and resistors around it. Take the time to look at each of these and touch up soldier if needed.

Got everything mounted and now I am just waiting for my B10k pot (apparently I only had plastic shaft trimmers on hand) and the mounting hardware for the OLED LCD.

Notes:
1) Trim the pins of the LCD header so the LCD is not higher than the jacks.
2) All of the LEDs on the PCB are orientated with the anode on the lower pad.
3) There is a small jumper that is needed if you use the 12864WD LCD I have in the BOM. The jumper is located just under R4 and C31.

Resources:
Mouser Project I created
Monome TeleType Hardware GitHub
Monome TeleType Firmware GitHub
Lines Forums thread
Muffwiggler Forum thread

Plum Audio EuroScope

This is a project that takes the cheap JYE Tech DSO150 handheld oscilloscope and making it mountable and usable in your eurorack. I took the gerbers from Plum Audio’s Github and had some boards and panels made from JLCPCB and was really happy with the results.If you do not want to get the PCBs made yourself you can get them from Pusherman’s Shop.

You do have to be careful what JYE Tech DSO150 you choose to use since there are 2 major version. Here is the Amazon link to the one I used that worked perfectly.

L-1 Microcompressor Stereo

I wanted..no, needed a eurorack compressor and this fit the bill perfectly. Stereo, sidechain and CV for makeup was the things that sold it on me. This was a super easy build since 80% of it was all through hole parts. The hardest part of this build was finding the THAT4301 ICs. A member over at MuffWiggler forums hooked me up for a pair at a great price. I wanted to try out the new Befaco Bananuts and added some matching synth pointer knobs.

The more I incorporate in my case, the easier it is to pick it up and go. Many people use external effects and get way more features but I really wanted something more self contained. I am extremely happy so far with this.

Antumbra ATN8

The ATN8 is Inspired by the Mutable Instruments Shades in a nicely small package. The ATN8 is an eight channel signal processor. It can be used as an attenuator, attenuverter, offset generator, mixer and CV source.

PCB & Panel are from Pusherman’s store

ICs are mounted and out of the way!
That was not so bad
Need to straighten up the pots and test this beast out
We have lift off!

I was able to give this a quick test in my oscilloscope and it seems to be working properly. Time to some LFOs throgh it and attenuate to taste.

Cons:

After I got the ATN8 all patched up I noticed that the pots are VERY close to the input jacks and makes the knobs almost unusable. I am used to the “micro” modules that are coming out these days and my sausage fingers play nice with most of them, but this one is tight. Its mainly going to be used for “set and forget” type of patches so it should be fine.