Crimps is a 4HP module with Logic, Inversion, Rectification, Min/Max, And/Or, a noise source, and a sample and hold circuit. I was looking to make a Sample&Hold module, with some extra features. That sounds like the Mutable Instruments’ Kinks.
Kinks is open source, cc-by-sa, so we can build from it if we also open source the derivative. I’ve totally rewritten the schematic and PCB, but the featureset and interface is identical (sans LEDs). The design files are available on the same license.
First version is designed and being manufactured, prototype. The V1.0.1 board is in and tests okay: some parts are on wrong so it’s tricky to build, but actually works. You can see in the picture above that the transistors are upside down and the JFET is a tacked-on THT version (J112). V1.2.2 is available with the parts on the right way around, looks much cleaner.
The S&H calls for a better-than-average grade capacitor and opamp, but I’m going to try it with plain cheapies first and report back here if we really need to use the fancy opamp. I expect it to change the hold-time and droop. Update: using a plain opamp where Mutable specified a special one is not great for performance, we need headroom between the negative rail and your input signals, so a rail-to-rail opamp is a good idea, and a TL074 doesn’t keep the S&H quiet. If you reduce the noise volume to +/-3V by changing R27 to about 330K, then a TL074 should work. I’m happy with the higher voltage and part cost.
Power draw is 15mA on each 12V rail.
| Price | Note | |
| PCB/Panel set | $20 | |
| Full Kit (incl pcbs) | $70 | many small parts |
| Assembled & Tested | $110 |
Build Guide and BOM for self assembly v101 and v121 and an ibom.