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Building A Big Modular Synth From Scratch - A DIY Video Diary
Old 15th April 2019
Gear Nut

Building A Big Modular Synth From Scratch - A DIY Video Diary

Building a big modular synthesizer. My Diary – part 1: From clumsy to skilled / from soldering simple cables and plugs to building a wall of synth modules / a daring challenge / a tough mission or a desperate attempt? / I´ve set out for a destination far, far away! And this is my diary. Watch part 1: The Beginning

Old 15th April 2019
Gear Nut

Building a big modular synth - day 2

Building a big modular synthesizer. My Diary – part 2: The first kit has arrived. Just for doing some exercises. Now I´ll find out if my soldering skills are sufficient to start building a modular synth. But let´s have a look what´s in this little kit at first.

Enjoy your day!
Old 17th April 2019
Gear Nut

Building a big modular synthesizer. My Diary – part 3: Soldering the circuit – and some thought while doing so. If it works, then the next step will be into real Eurorack.
Enjoy your day!
Old 18th April 2019
Lives for gear
ImJohn's Avatar

Congrats on starting a modular synth and digging deeper into DIY! It can be a long and sometimes frustrating journey but it will be rewarding I'm sure.

Some tips on soldering:

Most components should sit flat/flush against the PCB. It's not always possible with certain ones though, but resistors, diodes, chips, chip sockets, axial capacitors (wires come out of opposite ends), and many other components as well. Radial capacitors (wires come out of the same end) often wont sit completely flush depending on the way the board was designed and component value used but there is no thermal concern with them or need to have them raised up. Typically small non-power transistors will sit up fairly high off the PCB and I believe this is typically done to help protect them when soldering.

It's a standard practice to place the smallest or shortest components on the board first, like resistors and diodes first, and the tallest components last like pots and jacks last. I work this way and just set the PCB upside down on a Silicone mat (either a special one made for electronics or something I bought at a kitchen store to set hot pots and pans on ). This way I can keep the components flush with the board more easily.

And as you mentioned in your video, it's helpful to not fully populate the PCB before soldering so it's easier to get to the solder pads with the iron and solder. There is no set number since it depends on a lot of variables but I might typically place anywhere from 1 to 30 components at a time before soldering.

I wouldn't bend over (cinch) the legs of chip sockets (or even the chip legs if soldering them directly without a socket) since removing it later if it needs to be replaced might be extremely difficult. What I'd recommend is to turn the PCB upside down and lightly solder just one of the middle legs, then turn it back over and check if it's sitting flush. If it isn't apply some pressure to it while reheating the solder joint and you should feel it snap flat to the board. Once it is sitting flush solder all the other legs and then resolder the first one you did last.

A note on a mistake I made once! Be careful to not apply too much solder when soldering chip sockets, especially for the type of socket where you can't see the top of the PCB once the socket is sitting flush. I did this once many many years ago where the solder shorted one or more pins together underneath the socket and it was a nightmare to figure out what was wrong and an even bigger nightmare to repair the product and I was very lucky to get it working again!

You might want to get a pair of flush cutters to trim the excess leads after soldering. The diagonal cutters you used in your video are sort of OK but they leave a lot of excess lead sticking out. Flush cutters are like fingernail cutters only not curved. They allow you to cut off all the excess lead sticking out past the solder. The Hakko CHP-170 is pretty decent for the price, only about $5 and should last a long time for occasional hobby use. Get one of those or similar and see how it works for you. You could get something much nicer like the Erem 2422E but those are over $50 . . . but might last you a lifetime? If you start with a cheap $5 one, once it wears out consider getting a much better one or just keep replacing the cheap ones, which ever makes the most sense to you.

Here's my favorite soldering tutorial, even though it's an older one. I agree with all they say except for trimming the leads before soldering which is only something someone might do when building rocket ships etc?

The Synthesis Technology General Assembly guide would be good to read through, even though certain items might not apply to some of the things you will build:

There is an active DIY section on Gearsults you might want to read through:
and also a good one on Muff's Modular forum:
MUFF WIGGLER :: View Forum - Music Tech DIY
Both of the above forums tend to be discussions of subjects way beyond the basics but if you look through and do searches you'll find information that will be helpful to you. In particular look at this one on Muff's:
MUFF WIGGLER :: View topic - DIY learning resources

Best of luck!
Old 23rd April 2019
Gear Nut

Building a big modular synth from Scratch

Hi John! Thank you very much indeed for such a comprehensive and extremely helpful answer/comment! Great!Thank you also for the links. Wonderful sources of information and knowledge, which will definitely help me proceeding in my project.

My reply of today is a rather short one:
Building a big modular synthesizer. My Diary – part 4: Power supplies for modular synthesizers - looking for the best alternative.


Enjoy your day!
Old 28th April 2019
Gear Nut

Building a Big Modular Synth - Part 5

The adventure continues:
Building a big modular synthesizer. My Diary – part 5: Building the first power supply and a makeshift case only for testing..... and having a look at power busses
Enjoy your day!
Old 28th April 2019
Hi Rolf, these videos are very enjoyable!

Looking forward to follow your journey until one wall of your apartment is a huge modular synth
Old 24th June 2019
Gear Nut

Building a Big Modular Synth from scratch day 17

Building a big modular synthesizer. My Diary – part 17:
Success at last! The clock divider works. And I´ve made a clock generator too – on the way.
Enjoy your day!
Old 24th June 2019
Happy that you posted again, kinda forgot about your project, and didnt know you posted updates after the last video you shared here.

Now I have some catching up to do
Old 27th June 2019
Here for the gear


I started 2012 with my DIY modular and it does teach you a lot on synthesis,

keep up the work and don't let you down if something does not work as expected.

I myself am not yet finished cause sometime a lot happens in life

And always remember if it is a pure DIY modular - you can do what you ant to :D
I found Eurorack panels too small, but Motm too big, so I simply decided to rebuild my panels in 4Uish with +- 15 Volts an 6,3 jacks :D

Good luck and lots of fun an little frustration
Old 3rd July 2019
Gear Nut

Building a big modular synthesizer. My Diary – part 18:

Finishing the clock generator - a quite flexible one by the way - and solving some mechanical problems. I love goofing round with my new module! Enjoy your day! Rolf
Old 13th July 2019
Gear Nut

Building a big modular synthesizer. My Diary – part 19:
A mysterious mistake is hiding in the deepest depth of the module.
Enjoy your day!
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