In most classic pedals, there is some component which is often impossible/difficult to find or expensive and it is the one which, of course, gives the best sound or the legendary original tone . In this case the Fasel inductor from the first series
There are several options in the market: The Dunlop Yellow/Red Fasel, TDK, Sabbadius Soul Inductor, Coloursound Inductor, Wipple inductor, SOD inductors, miniature audio transformers and coils from industrial filters.
I don’t think I’ve ever built anything with an inductor, though this module apparently uses 28 of them:
I’ve never believed in “legendary original tone” from magic old parts. It’s just some copper wire wrapped around a lump of iron. The circuit has changed too, the original called for 500mH but we found it sounds best for synthy sounds at 200mH. shrug.
Does anyone know other simple resonant bandpass circuits this simple without inductors? I am looking for something to use in a hihat module. It does not need CV…
Looking into this more, is there a finalized version of this schematic? One with all of the stuff with the op amps and voltage dividers sorted out? A “master”? I’d like to throw this on a board…
Cool! But this is not easy to be tuned (change frequency with a pot) right?
Probably I need a state variable filter for this… but then I would need a dual gang pot…
I am looking at the mutant hi hat as a kind of blueprint and they have only single gang pots on their BOM. There is a single LM13700, but this is used for the envelope, I guess:
Lo-fidelity original VCAs replaced by OTA-based modern VCAs
I am wondering what they are doing there…
@jaradical thanks for the link, the website is VERY nice! good explanations and a lot of stuff!
I am reading through the filter article now, to see if I can find what I need
ElectroSmash - Vox V847 Analysis The electro smash website is also very good about analyzing circuits. From my understanding of how filters work, you’re not going to get high resonance, and certainly not a controllable resonance, without a feedback stage in the circuit. At least that’s how it is in my mind.
Wow, took me a few days to catch up with this topic.
Awesome work everyone
Very nice to see all different building styles
Here’s what i’ve been working on yesterday, the safety valve vca. I build tube amplifiers so i do a lot of point to point wiring. I have like 60 of the little op amp pcb’s for 2 euros. They are peak indicators from a velleman diy audio mixers. Swapping out some components make them very handy opamp pcb’s.
