There are a few quite detailed pedal analysis posts, like this one for the DS-1, on this website: https://www.electrosmash.com/boss-ds1-analysis
Maybe it helps with analyzing your circuit. Cheers, Gabor On Wed, Nov 29, 2023 at 11:52 PM robert bristow-johnson < [email protected]> wrote: > > On 11/29/2023 5:44 PM EST Jens Johansson <[email protected]> wrote: > > > > > > Thank you for all your great advice so far! It gives some really good > hints which trees to consider barking up, so to speak. Well, I first have > to become multicellular, and evolve eyes, then find the trees, but you get > the idea. > > > > I enclose the full schematic if anyone's curious, my guess was that the > first three filter stages (C1R1, C3R2R3, and C4UA2) could be approximated > with stuff from the cookbook. Just loading the schematic into > LTSpice seemed to confirm this somewhat. Also the stages after this more > complex "fifth order" section (C9R7?, C12C13R11R12C14A) looked like they > either are inconsequential or kind of map onto the more normal filter > cookbook topologies too. The "N" ground is the midpoint between the two > power rails for the opamps. The "ground ground" is the negative rail. > > > > (It's not the greatest distortion box and also not the worst. Peak 1990 > technology. On the other hand my hope is that a simulation could run in a > couple of hundred CPU cycles and not need either bluetooth, AI or a built > in web browser. I was planning to just slap the code on github if I ever > got it working. I would use JSFX because it's so easy to prototype stuff in > this language) > > > > Okay, so all questions got answered. Your original post was enough > because it's 0 ohms output impedance driving the circuit from the left and > infinite ohms input impedance for the tone circuit output. > > Are you gonna make one of use to node-voltage analysis and come up with an > H(s)? It's a pain in the ass and because there are five separated > capacitors, it's potentially a 5th-order transfer function. Might be a > pain in the ass, but I could do it. Someone with access to something like > SPICE can maybe do it. > > Anyway, once the transfer function is identified (with parameters > associated with the positions of each potentiometer), then the transfer > function can be broken into cascaded sections and maybe we can match it to > the prototypes in the Cookbook. > > This analysis is something that I was anxious to do when I was younger, > but I am lazier now. All I can tell you is that it is an LTI circuit and > **must** have a consistent transfer function H(s). Whether there is any > pole-zero cancellation (that will reduce the order) I don't know yet. > > > -- > > r b-j . _ . _ . _ . _ [email protected] > > "Imagination is more important than knowledge." > > . > . > . >
