Korg PS-3300 Resonator Circuit Analysis: Mutant Multiple-Feedback Bandpass Filter

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0:00 -- Introduction
2:02 -- Bandpass filters
2:57 -- Transfer function analysis
10:55 -- Filter parameters
13:33 -- Sallen-key highpass filter

[@eshekerjian]

I’ve always viewed this topology as a MFB LPF, but the input signal is applied to the grounded capacitor and the input resistor is grounded instead. The grounded input resistor can be omitted for simplicity with negligible affect on the frequency response

[@bonafontciel]

I saw your videos a while back and didn’t subscribe. Now I did before I forget about this channel🎉

[@petegreenwood2793]

Another great video Aaron - loved the algebra walk-through!

[@Lantertronics]

Thanks!

[@DemMusel]

Great video. Would love to see a similar video about the circuit of the Buchla 291 filter ,whcih seem to be a bit of a mystery for a long time

[@Lantertronics]

Oh man... I'll be honest, I've spent hours staring at the 291 schematic and can't really make heads or tails of it. At first I thought it was a more-or-less standard state variable filter, but it's definitely not.

[@DemMusel]

​@@Lantertronics Don Buchla has been asked about the design before his death and he stated that Max Matthew based the design on the formant filters of the Bell lab synth when doing Vocoder studies back in the day. there is also an interesting discussion on ModWiggler with the best guess being it a Twin-T design of some sort..

[@acurara0113]

Native japanese subscriber here, I suspect it's 1枚の基板ニハ同包をつかう. meaning "use same package for a single pcb". I'm not quite sure about the ニハ同包 part since it doesn't quite make complete sense in this scenario nor even make natural japanese. ニ(ni sound) can be ニ(kanji for 2) or even be =(equal),　ハ(ha sound) can be 八(kanji for 8).I hate japanese language lmao.包 is not even intelligible… or it could be just right. Without the doubting part it's "one single pcb", "same" and "use". hope you can make use of this info.

[@acurara0113]

I think I found out! it's 一枚の基板ニハ同色をつかう, meaning "use the same color for a single board"! I think the "color" is related with the table at the lower left of the pdf.

[@akiatoji5088]

Bilingual Japanese American here, ​@acurara0113 nailed it. It's proper Japanese and makes perfect sense. The note says to use the same color-coded HTVP873D on the same PCB. This also means using the same C105-107 and C108-110 values according to the table. I'm guessing HTVP873D was graded by some parameter and color-coded accordingly. This way, they can use (more or less) matched HTVP873D on the same board.

[@deviantmultimedia9497]

Great video, man! As for the Sallen & Key filter, given that gradual roll-off, that's likely a Bessel curve, which would roll off all the inaudible stuff but ensure a maximally flat phase response for all the passband frequencies. I wouldn't be surprised if that 47.754Hz is literally just the highest possible cutoff you get with a Bessel curve in a single Sallen/Key op amp stage. Not a bad idea actually, I'm definitely going to steal it. Precision AC coupling! 😂

[@clausanders2886]

１枚の基板のハ同包さつの勺 means: 1 PCB on the same substrate. I.e an array of resistors with the same value, hence the HTVP873DX3 (with 2 resistors).

[@clausanders2886]

@@akiatoji5088 Why are you insulting me?I don't delete comments, and the handwriting was terrible.No OCR would be capable of reading the kanji.At least I got the gist.

[@akiatoji5088]

@@clausanders2886 I replied multiple times and they got deleted, if it wasn't you I take it back. Yes, handwriting is really bad so 色 looked like 包 and even us natives were scratching our head, I give you that. But the rest of it wasn't that hard to read, and it's not just one Kanji you had wrong. The Japanese phrase you came up with (and therefore the English translation) just makes no sense. I don't mean any insult, it's called out like it is, that's all.

[@clausanders2886]

@@akiatoji5088 I forgive you ;-) 問題ない。I would have never guessed　色！I noticed the ハ／八 inconsitence. If you just want to correct me, please just say: you read this Kanji wrong and don't say 'your interpreation is gibberish'. I7m trying to learn.

[@shean4]

Thanks for another interesting analysis. Was wondering if you plan on doing any analysis of circuits that used the Norton op amp (eg LM3900)?

[@Nopp3]

Ever looked at fonitronik's triple vactrol resonator (euro module)? its essentially this circuit, though he cites the ps3100 as the origin. It doesn't have the blend function, just the filters. but they can be patched individually on the older version.

[@GunnarLoeb]

I am 41 and have recently slept bad. I got hit with something and stopped exercising. This had a bad effect. I am in a abusive relationship which also make me nervous. I know I need to stop bingewatch KZbin in the bed when I am about to sleep. Dr Berg is right. Ideally put your phone in a another room and 1h before the time you want to sleep

[@4DRC_]

It looks almost like an inverse Sallen Key, for lack of better words

[@christdolphin69]

voltege