You may want to go to General Guitar Gadgets & look under Projects & then click on filters/other. There's one or two that you might like. Otherwise, there's a few if you google filters, phase, EQ, or whatever you like. Then click on images to save some time. If you see something that you like, click on the image & it usually takes you to the site with a description or even instructions for the build. When I play bass for recording, I sometimes use a Bronx Cheer box that has a bunch of tones that you may like.