# Help Simulating a 9V Battery Powered Sallen-Key Filter in LTSpice **URL:** \ **Category:** DIY STUFF\ **Created:** [October 13, 2022, 9:03pm UTC](https://lookmumnocomputer.discourse.group/t/help-simulating-a-9v-battery-powered-sallen-key-filter-in-ltspice/5536 "2022-10-13T21:03:38Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![space\_merauder](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/space_merauder/32/22845_2.png) [@space\_merauder](https://lookmumnocomputer.discourse.group/u/space_merauder)\ **Post date:** [October 13, 2022, 9:03pm UTC](https://lookmumnocomputer.discourse.group/t/help-simulating-a-9v-battery-powered-sallen-key-filter-in-ltspice/5536/1 "2022-10-13T21:03:38Z")
Hello all! This is my first post here. I’m seeking help because I am at a complete loss! I’m designing a synthy guitar pedal and the VCF design has been eluding me. My first concept was to try and modify the Moritz Klein diode ladder filter for a single +9V power supply, but I found that very difficult. So I did a little research and found this awesome website of designs by Osamu Hoshuyama, many of which are designed for a single +9V power supply. I found this [very cool Sallen-Key VCF design](https://understandcircuit.seesaa.net/article/201010article_2.html), and attempted to simulate it in LTSpice. However, for some reason, it is not working at all. I was hoping someone with more LTSpice experience might be on here who can take a look at my project and tell me what I am doing wrong. Here are the LTSpice project files: [https://drive.google.com/drive/folders/1Q9vMDw36i2x64o5-JBonkNLfrEOExlsP?usp=sharing](https://drive.google.com/drive/folders/1Q9vMDw36i2x64o5-JBonkNLfrEOExlsP?usp=sharing) Thanks! ---
**Author:** ![Krakenpine](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/krakenpine/32/3263_2.png) [@Krakenpine](https://lookmumnocomputer.discourse.group/u/Krakenpine)\ **Post date:** [October 14, 2022, 7:46am UTC](https://lookmumnocomputer.discourse.group/t/help-simulating-a-9v-battery-powered-sallen-key-filter-in-ltspice/5536/2 "2022-10-14T07:46:44Z")
There were too many mistakes that I don’t remember how to list them all, so here’s just the fixed file: [https://krakenpine.kapsi.fi/salajako/Totem%20Pole%20Sallen-Key%20Filter%20kp.zip](https://krakenpine.kapsi.fi/salajako/Totem%20Pole%20Sallen-Key%20Filter%20kp.zip) ---
**Author:** ![space\_merauder](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/space_merauder/32/22845_2.png) [@space\_merauder](https://lookmumnocomputer.discourse.group/u/space_merauder)\ **Post date:** [October 14, 2022, 10:34am UTC](https://lookmumnocomputer.discourse.group/t/help-simulating-a-9v-battery-powered-sallen-key-filter-in-ltspice/5536/3 "2022-10-14T10:34:12Z")
Thank you SO much @Krakenpine !! I really appreciate it.