This one feels a bit arrogant, since I have nothing but respect for Émilie and MI. The best kick drums I made were with the original Ripples, and I still don’t get why I sold mine back then… Well, here we go with some modifications for the 2020 version! As reference, especially for part numbers, use ripples_V90 schematic, 16.12.2919. I know, telling folks what to do is lame, but if you purchase pre-built, get the MI build. Mutable Instruments rule at least 180% more than clones!
Fair use policy: the modifications described here are for non-commercial applications only.
Higher drive for Input 1
If you want to increase the overdrive for Input 1, simply reduce the value of R58 (100k). This can very easily be done by wiring a 47k to 100k resistor across the IN1 jack socket tip lug and IN1 volume pot wiper (middle pin).
You can prewire filter feedback to IN1 by decoupling the NC lug of J1 (the IN1 socket) from ground and wiring this NC lug to the tip pin of J9 (VCA OUT) via a 33k resistor. If no jack is plugged into IN1, pulling up the Level 1 pot will introduce some sweet filter feedback. Cool side-effect: when using HP out or BP out, you can “misuse” the VCA as CV controlled feedback by just feeding some CV into the VCA CV. As for how to prep J1, check the pic at the top of the page.
Passband level loss compensation on/off
Part of the signature sound of Ripples is that the circuit compensates for level loss when resonance is turned up. In some cases you nevertheless might want to have your sound thin out, and this can be done per on/off switch inserted between C16 (4.7uf) and R25 (33.2k). Physically easiest way to do this: take out C16 and wire the terminal that is not connected to R25 back in. Attach wire to lifted terminal of C16 and empty solder pad on PCB. Doing is this very much a matter of taste – I personally keep level compensation active as per original schematic.
Reduce maximum resonance
For many applications I really like that the Ripples offers resonance in oodles. Yet, sometimes I like it a tad more restrained, and oddly I prefer this mod to just not turning resonance all the way up –luxury problem stuff, eh? Simply wire a 6.8k to 8.2k resistor between the junction R26-R27 and ground. If desired, put an on/off switch in between too.
Individual pole outputs
Tap pole outputs at filter cap-amp junctions labelled LP1, LP2, LP3, and LP4 on the schematic (section A), so you have the -6, -12-, -18, and -24 lowpass stages available for mixing and matching. Even without pole mixing I love using the -6db output on its own! A lazy version of this is simply to connect a 4.7uf cap followed by 1 k resistor per output. The volume of the individual outputs is a lower here than the proper HP, BP and LP outputs.
If you want to bump their level up and have this properly buffered, use a quad op-amp and wire each pole output as follows: pole to 47k resistor, which goes to positive input of op-amp. Feedback resistor between op-amp out and negative input is 100k (optionally, have a 22pf capacitor in the feedback path too), and 1k resistor after output, which is then connected to jack socket. This is what I did for usage with an external VCA.
Yes, we can make all sorts of different filter responses once we feed the individual pole outputs to extra outputs. If you’re interested, here’s an excellent resource, and, of course, here’s another excellent page on the matter.
If you want to use your internal VCA with other filter responses than 2 pole or 4 pole lowpass, or simply use that VCA with other filters, do this: break the connection between SW1B and C17 (4.7uf). If you don’t want to cut the PCB trace, just lift C17, so that its bottom is disconnected from the PCB terminal, then and insert a jack socket as follows: PCB terminal (connection to SW1B) goes to NC lug of your socket, and bottom of C17 goes to tip lug of your socket. When a jack is plugged, this then breaks the connection between SW1 and VCA and sends in whatever comes from your cable.
Variable volume version of VCA Insert/ VCA Overdrive
While I did the VCA insert, I swapped the position of R24 and C17 as I found it easier to wire up some VCA input attenuation. [On the Roland SH101 VCA in is wired that way (resistor before capacitor), so I thought, hey…]
First replace R24 (100k) with wire/solder. Then insert a 10k resistor and a 100k potentiometer in series between the SW1 and C17. This way, you can attenuate your VCA input a little more than in the original, which might come in handy when handling higher resonance amounts, and easily overdrive your VCA input. The result is a nice (sometimes not soo nice) granly acid-y overdrive.
Still testing this a bit and might actually settle on 10k resistor and 200k potentiometer in series for a wider range.