these links may be of interest/use to many:
www.doepfer.de/a100_man/a100t_e.htm
https://doepfer.de/a100_man/a100m_e.htm
a good, comprehensive guide to subtractive synthesis that's very applicable to starting out with a modular synth, I'd recommend all of Gordon Reid's Synth Secrets articles for Sound on Sound.
The electronic Engineers Bible - Lessons In Electronic Circuits
A great resource on the flexible and simple yet so adaptable 555 timer IC
A very useful wiki page for anything from those into lunetta style synths to digiatal logic and much more - lists every 400b ogic ic there is!
logic info:
https://www.homofaciens.de/technics-base-circuits-logic-gates_en.htm
https://www.electronics-tutorials.ws/logic/logic_1.html
https://www.niser.ac.in/sps/sites/default/files/basic_page/logic%20gate%20circuits.pdf
http://hyperphysics.phy-astr.gsu.edu/hbase/Electronic/logfam.html#c2
gate oriented logic stuff:
https://www.cs.bu.edu/~best/courses/modules/Transistors2Gates/
https://en.wikipedia.org/wiki/List_of_logic_symbols
https://en.wikipedia.org/wiki/Logical_connective
https://electronicsclub.info/gates.htm
https://www.frontiersin.org/articles/10.3389/frhttps://www.researchgate.net/profile/Siegfried-
Gottwald/publication/260990913_Fuzzy_Sets_Fuzzy_Logic_Fuzzy_Methods_with_Applications/links/0deec534eb0320a3d9000000/Fuzzy-Sets-Fuzzy-Logic-Fuzzy-Methods-with-Applications.pdfai.2020.00059/full
The ultimate page on serge info links!
http://www.serge.synth.net/documents/index.html
https://www.avarethtaika.com/how-to-make-noise/50-simple-patch-ideas-for-modular-synths
[above/below pages taken from the best sound design blog on the planet: https://www.avarethtaika.com/ ]
https://www.avarethtaika.com/how-to-make-noise/how-i-use-granulators
https://github.com/capital-G/typhoon-manual
https://www.falstad.com/circuit/
http://www.zpag.net/Electroniques/Kit/The%20Forrest%20Mims%20Engineers%20Notebook.pdf
https://www.electronics-tutorials.ws/
https://www.allaboutcircuits.com/technical-articles/
https://en.wikipedia.org/wiki/Gilbert_cell
https://northcoastsynthesis.com/news/understanding-stabilization-capacitors/
https://sdiy.info/wiki/Schematics_and_manuals
https://electro-music.com/forum/links.php?id=28
https://electro-music.com/forum/viewtopic.php?t=56660&postorder=asc&sid=a6038b35708ee2dd49005a87ed8a992a
https://synthracks.com/
https://secretlifeofsynthesizers.com/the-strange-heart-of-the-roland-tr-808/
https://secretlifeofsynthesizers.com/roland-tr-808-noise-transistor-update/
https://www.researchgate.net/publication/267629876_A_Physically-Informed_Circuit-Bendable_Digital_Model_of_the_Roland_TR-808_Bass_Drum_Circuit ;
https://www.researchgate.net/figure/TR-808-bass-drum-emulation-block-diagram_fig2_267629876
https://en.wikipedia.org/wiki/Line_level
https://www.sweetwater.com/sweetcare/articles/whats-the-difference-between-mic-instrument-line-and-speaker-level-signals/
https://sound-au.com/articles/balanced-io.htm
https://www.youtube.com/watch?v=6NlI4No3s0M
https://store.cherryaudio.com/
https://en.wikipedia.org/wiki/Karplus%E2%80%93Strong_string_synthesis
http://www.csounds.com/manual/html/MiscFormants.html
https://writingcooperative.com/zettelkasten-how-one-german-scholar-was-so-freakishly-productive-997e4e0ca125