Thank you for your kind words!

Gonna give us a 5U LPG, STG? You rock!

@@Tofu_Pilot thanks for the kind words but if I do it will be a while

me too and so am I! good luck, brother!!

You are welcome!

Will do! There's no classes like these where anyone else lives either, because none of those places have anything like me. ;)

@@Lantertronics Haha, agreed ! Good thing we got the internet so that these teachings can spread all over the earth! Happy celebrations and Greetings from Greece

I've built that circuit (the one from the Music Easel). I've never fully wrapped my head around how it works. It's somehow using the response of one vactrol to linearize the other.

@@Lantertronics Wow, that sound wild considering the variance/tolerance of vactrols.

You've largely confirmed a hypothesis of mine, which is that 220 pF cap is really intended to do its thing for the "combo" mode and just happens to tag along in the other modes.

I'll do one as soon as I understand it myself.

@@Lantertronics wow cool :))

Yup, it's a two pole instead of one pole on a tone control on electric guitar, but it's really just a two-capacitor passive RC filter.

I liike it!

There is another term: _"genericide"_ where your brand name becomes the generic name for the _thing,_ and it becomes impossible to renew any trademarking on that name. Google is worried that the verb _to google_ could become the generic word for Internet searching, and Lego comes down like a ton of plastic bricks on anyone using the name Lego to describe non-Lego plastic interlocking bricks.

If you have capacitors and inductors you can get a resonant circuit -- but if you're restricted to just using capacitors you need to use active elements to get resonance, basically via feedback. I have a couple of videos talking about the kind of sound you're talking about. One about four-pole filters: kzfaq.info/get/bejne/eriHjZZqxsuWj58.html And another about two-pole filters: kzfaq.info/get/bejne/nJ55h7WYtc3enY0.html

Alas, lock-in amplifiers are an RF thing and beyond my current areas of expertise. As far as books go, I recommend finding a copy of "Musical Applications of Microprocessors" by Hal Chamberlin. It has an excellent chapter on analog circuits.

my bad... i got a horrendous habit of asking questions in the middle of a video because ill totally forget what i was going to ask or to even ask at all

Heh, yeah those prices are crazy. You should see the prices on a Yamaha CS-80! It's like old guitars; they're that price because they're old and rare. You could buy modern clones much cheaper. In the case of tuning the filter, it's largely for predictability, in particular if you can tune the filter cutoff to a 1/v per octave standard (or whatever the standard is) to match your oscillator, the filter can track the pitch so each note will have a similar harmonic structure. Regarding a video, the one to watch is my video on exponential converters: kzfaq.info/get/bejne/kL16m6ShutPKdYk.html As always, thank you for your kind words!

@@Lantertronics lol, i have watched that before and that's the one i have in front of me right now. at my school i was among the best in maths and physics, but that was some time ago, it's like starting over again. wiki: baby. however, you would love the pcb's i design. did you see that video the KZfaqr: Fran published a few days ago on transistors from the 60ties?

@@AnalogDude_ I haven't seen her video yet but I'll check it out; I love Fran's videos.

@@Lantertronics These guys where absolute hero's in my view. How do you come up with the idea? that adding impurities to Germanium or Silica you can create a (semi) conductor and come up with the mask design of a transistor. even the idea that you can grow crystals! ... by pulling a rod.

​@@Lantertronics Hmmm, professor, how much current can you pull from a TL072 ... and a CD4000 series IC, since they pretty much source power / current from the internal power rails albeit via transistor's / FET's it should be limited only by the power supply of the circuit, right? i often use a certain circuit "made" by Don Buchla and I'm really curious to know how much power you can pull with a opamp, at home i use the Mitsubishi M5218A ... and if I'm correct they should deliver 20 mA. i got one for ya. Korg_700s_Service_Manual.pdf Would you do a video on this Filter? it's different than all ... and it sounds cool. mylarmelodies: Vintage Synth Lab VCF-74 Eurorack (Korg Minikorg 700s) Filter Demo kzfaq.info/get/bejne/kMVymMZlnrnTZXk.html

Usually your best bet is just to go with the defaults in whatever microcontroller library you are using.

@@Lantertronics hmm, micro controller, somehow misses the point of a analog synthesizer. i haven't programmed a micro controller for something like 5 years or so. accept a hello world thing in a arm32 bluepil, not so long ago. it kinda sucks, 3v333 hardware and scaling down a 10 v.p.p. signal. haven't looked into that yet.

@@AnalogDude_ Ah, sorry, I didn't realize the context of your question. If you're using an analog signal to drive the brightness of an LED you can just drive it directly. PWM is only really necessary when you're driving it with something fundamentally digital.

@@Lantertronics there might be a way to achieve this without "software", have to look into that. will keep you updated. currently i don't have a multi meter, mine died.

@@AnalogDude_ Check out the various circuits Buchla uses to drive the LEDs in Vactrols; you can just use them to drive regular LEDs.

The idea that there's some special batch of 1N34A Germaniums that Bill Finnegan found is kind of absurd. There's silicon based Klons that sound awfully close to the Germanium Klons, given adjustment of other things in the circuit so the diodes kick in at the same point. The main interesting thing about the Klon is the way some of the undistorted signal is mixed with the distorted signal.

@Lantertronics thank you for the level headed answer that I couldn't have said better myself. There's a whole channel I found dedicated to it and the guy has no ee knowledge at all. Spends a fortune on diodes and gear but never shows a schematic, waveforms or any empirical data of any kind but has a ton of subs. I just sold my spark amp and regret it now because I'd like to have done a teardown. It's the best practice amp ive ever had but I got a helix for free and I just run it into my 2.1 jbl studio monitors now. The hunt for tone has never been a concern of mine as I've always dedicated my time to being able to play what I hear in my head. It took a long time. I'm 44 and I can confidently say I'm there without any bs or boasting. I'm going to record an ep soon with a cover and 4 originals and never release it. I plan to pay a professional engineer to take the compositions and reamp and master them as a gift to myself. A buddy is going to play drums and add some diy synth from circuits we love. I'm going to cover "US and Them" or pigs from the animals album with a tasteful combination of shredding and synth in lieu of vocals. Haha. The cover song will melded into the ep as it's going to be one large piece of music. I'm going to try to get one of my favorite musicians to contribute a few riffs. He's not super famous so it can't hurt to ask.

I assume you mean OTA? Alas, there's no way to approximate an OTA with an op-amp. You immediately run into something like a parameter mismatch error in computer programming: the OTA has 3 input pins and the op-amp only has two. There's a "programmable op amp" with a 3rd input pin for changing slew rate -- that's not an OTA, but is an interesting chip used in the filter in the Polivoks, but that's a specialized thing.