I built an analog synthesizer from scratch. Here is how I did it...

um [Music] for as long as i've had an interest in electronics it's been a dream of mine to build an analog synthesizer from scratch it always brought a great deal of curiosity and excitement to me how turning different knobs on these mysterious devices would generate a variety of different sounds ranging from dirty and gritty to shiny and magical just after i had completed my master's degree in late 2019 i realized that i finally had both the experience and the resources to pull off my own synthesizer build so upon graduating i turned my eyes toward the mother of all modern synthesizers the moog minimoog considering that there is a wealth of information pertaining to the construction of the minimoog online i figured that this was the perfect synthesizer built for my own project there are even a few people who have already documented their own builds of this synth in their online blogs there are several resources online for information about the mini moog's construction but of all the online resources available the one i referred to the most was fantasyjackpalance.com this website contains scans of the minimoog schematics bill of materials wiring and assembly diagrams and much more at this point i had to make my first big decision the fantasy jack palance website contained schematics for two different versions of the minimoog oscillator board the biggest difference between them is that the newer oscillator was designed to be more stable over changes in temperature helping the instrument to stay more in tune in environments where the temperature would change significantly however the problem with trying to implement this design today is that it used a part that is rather rare and thus expensive to procure this part is the mu a 726 temperature controlled differential transistor pair the part that was used in the old version of the oscillator for the same purpose the ca 3046 is not too uncommon and i was able to find them on gmco for about four dollars a piece so for sake of simplicity i decided to build the old less stable version of the oscillator board and i would just have to deal with tuning the synth more often with that decision out of the way i started compiling a bill of materials for this project using the parts list from fantasyjackpalance.com after about two weeks i had found a source for every part on the list and was able to estimate the price of all of these parts at just over six hundred dollars i had obtained these parts from various vendors including digikey mouser nte partsdirect and others i even had to order a few less common parts from ebay due to lack of availability on other vendors now i had to have a circuit board to solder these components to and fortunately ralph who wrote the internet blog inaptly crafted provided gerber files for each of the minimoog circuit boards this helped me save a ton of time since this meant that i didn't have to design my own minimoog circuit boards so i downloaded the gerbers from ralph's blog and uploaded them to jlcpcb and put in an order for five of each board since that is the minimum quantity that jlc pcb allows in all there are six circuit boards in the minimoog the filter board the contour generator board the oscillator board the power supply board the rectifier board and the buffer board with all of these boards there is a lot of soldering and assembly work to be done but before i talk about assembling the circuit boards i should talk a little bit about component matching sometimes in electronics you need certain properties of two or more components to match with each other within a limit that is better than the rated manufacturing tolerance of those components for instance the oscillator board of the minimoog has three 15 kilo ohm resistors that are supposed to be matched with each other the resistors have a manufacturer stated tolerance of one percent meaning that their actual value is within one percent of that 15 kilo ohm value but this design calls out that they should be matched to better than that so if i start out with say 20 15 kilo ohm resistors and use a multimeter to measure the actual resistance of each of them then i can select three of the 20 resistors that measure as the same resistance value to the best that my multimeter can measure at that point i will have successfully matched those resistors this project also required matching transistors as well matching the transistors required creating a specialized circuit that supplies the transistors with a constant current so to match these transistors i labeled each transistor so that i would know which is which picked them up one at a time with a pair of pliers then placed them in my test circuit which was connected to my bench power supply following that i would record the value that my multimeter gave me and enter it into a spreadsheet with the transistors associated label number based on the measured values i could then sort the transistors into different bags so that i know if i pull two transistors out of any bag they are matched with each other and by the way the reason i use pliers to hold the transistors is because the transistor properties that i'm measuring are very sensitive to temperature and the heat coming from my fingers is enough to significantly throw the measurements off after ensuring that i had some matched sets of components it was time to pull out the soldering iron and get to work but before i started soldering i organized the components by type to make it easier to find the ones i need then starting with the oscillator board i got to work putting each and every component into its appropriate position on the board and soldering it in place i had started with the resistors and the ic sockets then added on the capacitors and jumpers when it came time to solder the trim pots i knew i was going to need a way to convert the pins on my trimmers to the pins on the board since i couldn't find a trimmer pot the same size as the ones on the actual moog board so i spun up a quick converter board with jlc pcb and was able to fit my pots on the board no problem and after installing all the transistors and ics on the board it looked really good following the construction of the oscillator board i followed the same steps to assemble the filter board the contour generator board the buffer board the rectifier board and the power regulator board after building the boards i decided to try performing a crude test on the oscillator board to make sure it was working here the oscilloscope seems to show the board producing a clean sawtooth wave on the board's first oscillator now that i had my boards assembled i needed to work out what kind of enclosure to put them in after doing some experimenting with the layout of the controls and determining the dimensions i would need for the enclosure i decided on this enclosure from circuit specialists i got my enclosure in the mail and did some more layout experimentation using the original mini mode control layout as inspiration i then use freecad to produce this layout with the center of each of the controls marked by the crossing of these lines i printed this page out on large paper and used it to mark where the drill holes would go on the actual enclosure after marking the drill locations i drilled them out with my drill press mounting the controls onto the front panel was a really exciting moment as it made it really start to feel like a real synthesizer was coming into being one last addition that i added to the enclosure later on in the project were these rubber feet so that the synth would sit level and wouldn't scratch any surfaces that it sits on with the enclosure and the boards all put together it was time to mount the boards and begin the process of wiring them all together i got these edge connectors that just slid onto the edge of my boards and gave me a convenient point to solder wires to these also make it convenient to remove and replace the boards as i wish for debugging purposes to make it convenient to solder to the pins after i've mounted the connectors to the enclosure i bent the pins of the connector about 90 degrees next i wanted to get a good idea of how i would fit the boards into the enclosure so i connected each board to its connectors and played around with their placement in the enclosure once i was happy with the arrangement i mounted the connectors and the boards to the enclosure with standoffs to keep them from shorting out on the enclosure's metal and to keep them appropriately spaced out at this point i had also installed some extra i o connectors to the back panel as well as the power connector power switch and a couple fuses the first part that i wired was the transformer and power input section of the synth here i simply wired the power input connector to the power switch and mains fuse then wired those to the primary side of the transformer the output of the transformer then connected to the input of the rectifier board that was the easy part of wiring the synth the remainder of the synth required me to carefully follow the wiring diagrams that i obtained from the fantasy jack palance website these are very complex and required many many hours of cutting soldering and connecting wires to the various boards and controls i started by only connecting the wires that needed to be connected only to the controls on the front panel as i connected wires i would verify that the connection was correct secure and then use a highlighter to mark that the connection has been made on the wiring diagram this helped me keep track of all the connections i've soldered and made wiring this very complex system much easier once the front panel was all wired and remounted to the enclosure i began wiring the rest of the instrument i started painstakingly connecting every wire according to the wiring diagram and as before highlighting the wiring diagram to keep track of all of the completed wires you'll notice masking tape in various places inside the enclosure i used these as labels for the various boards controls inputs and outputs of the system this labeling system was vital to keeping everything somewhat organized as i wired everything together as a first test after wiring i put all the boards back in the synth and connected one of the oscillator outputs to my oscilloscope here i could see it seemed to be working and outputting different shaped waves as i changed the wave shape knob i then connected the oscilloscope to a different part of the synth to test the filter section i triggered a note and adjusted the filter cut off knob and saw that the sawtooth wave that the oscillator was outputting was getting rounded off as it should be i also found that the sawtooth would start ringing as i turned the resonance knob up as it should and finally we get to the real test connecting the synth to my guitar amplifier and seeing what sounds come out [Music] as you can hear it seems something's gone wrong in the synthesizer one of the three oscillators on the oscillator board is really unstable the other two oscillators aren't producing any sound at all as it turns out there were a few mistakes that were made in the routing of the oscillator board that i got from the inaptly crafted blog after using the schematics and a multimeter to track these mistakes down most of them were fixable by just adding a few solder jumps on the board and i was able to fix one of the mistakes by cutting a trace on the board with a box cutter i also found that one of the capacitors on the oscillator board had gone bad so i quickly had to replace that after applying these patches to the oscillator board i closed everything back up and tried testing the synth again to get this [Music] [Music] now that sounds a lot better thanks to those oscillator patches i was able to get a really nice stable and clean sound out of my synthesizer now this was a very exciting moment for me in this project i was finally getting something resembling musical sounds from a synthesizer that i've built with my bare hands nevertheless i still didn't have a way to control the synth with some sort of keyboard like the original mini moogs have to fix this i was going to have to build my own custom midi controller so that i could receive note commands from a digital keyboard or computer and interpret them into an analog signal that the synthesizer understands so using my brain i concocted a schematic for a midi controller and used keycad to route a layout for it i reviewed this schematic in layout several times before sending it off to jlc pcb to be fabricated since the analog potentiometer chips i needed were only available in tssop packages this was the first time that i hand soldered some small surface mount packages for a project it actually turned out to be a lot easier than i thought and i was really satisfied with the results the final step for the midi controller was to program the arduino nano and give it the ability to interpret midi messages into synthesizer controls to do this i used the arduino midi library made by 47fx to handle the incoming midi messages and control the other components that i have on my midi board now this is where the fun begins i connected the synth to my computer through my audio interface which has a built-in midi interface i entered a few notes into reaper which is my music software and i set it to output midi commands to the synth and this is what i get [Music] [Applause] now to finish this project up i was going to have to fine tune my diy mini moog luckily there's a guide to doing just that on the forum retrosynth.com written by michael caloroso following these steps i was able to get all three of the oscillators to stay in tune with each other throughout the whole note range of the synth minus some minor bugs that i have yet to fix i officially consider my synthesizer to be complete now i'm just going to stop talking and let all of you hear just what kind of sounds this thing can make [Music] [Music] so [Music] so [Music] [Music] [Music] so hey [Music] [Music] uh [Music] wow hey [Music] i feel so excited to have finally built a synthesizer of my very own this is definitely a project that i'm going to be scratching off of my bucket list i'm not sure if i'm ever going to do a personal project that's this complex and time consuming ever again but nevertheless it was still a lot of fun and was completely worth it anyway that's all for now if you enjoyed the video i humbly ask that you please like share and subscribe thank you so much for watching until next time [Music] so [Music] [Music] [Applause] so [Music] [Music] you

Channel: Ryan Boggs

Views: 11,814

Rating: 4.9770117 out of 5

Keywords: NileRed, GreatScott, ElectroBOOM, LOOK MUM NO COMPUTER, Synthesizer, Moog, DIY, Simon the Magpie, Music, Piano

Id: PATlf0W3m7k

Length: 20min 7sec (1207 seconds)

Published: Mon Oct 11 2021

Reddit Comments

[u/Ryan_Boggs]

In this video, I describe how I built my DIY Minimoog clone. I hope that anyone who watches this can get some kind of entertainment/education out of it.

[u/newbjapan]

Stuff like this is insane to me. I envy anyone with this kind of intelligence and skill.

[u/terrapinsounds]

Sounds great! Now I want to do this!

[u/PC_query_man]

Impressive. Sounds awesome.

[u/getlostincanada]

Absolutely unreal!!! Great work!!!

[u/kharlos]

Incredible. I am so jealous

[u/Xcalism]

Very cool! Did you want it that size by the way? Seems quite big, guessing it could be smaller if you wanted?

[u/fiveonethreefour]

I enjoyed watching, you explained each step really well, congrats it sounds awesome!

[u/Chrisryanyoung]

You are fricken awesome dude. Watched the whole thing despite having no knowledge or experience beyond the operation of synths. P.S. fuck yeah shimmer