{"id":19,"date":"2026-04-11T13:07:08","date_gmt":"2026-04-11T13:07:08","guid":{"rendered":"https:\/\/www.gearip.net\/?p=19"},"modified":"2026-04-11T18:31:57","modified_gmt":"2026-04-11T18:31:57","slug":"inductorless-wah-guitar-pedal-effect","status":"publish","type":"post","link":"https:\/\/www.gearip.net\/?p=19","title":{"rendered":"Inductorless Wah guitar pedal effect"},"content":{"rendered":"\n
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Credits for the schematic to beavis audio research<\/a><\/p>\n<\/blockquote>\n\n\n\n

My son is playing the electric guitar, and I wanted to build an effect pedal for him rather than buy one. Many schematics are using inductors and are threfore harder to build because of this but I found a schematic that doesn’t need an inductor, the Optochopto: Fun with the Colorsound Inductorless Wah<\/a>.<\/p>\n\n\n\n

To be able to use it I searched for a “blank” pedal with nothing but the potentiometer and in\/out jacks. I got the Bespeco VM12 but there are a lot of other models out there. I needed one that had the 100K\u03a9 potentiometer. The good thing about this pedal is that it has plenty of space inside to fit a PCB and it even has a screw hole that you can use to mount the board. Probably for other pedal models that have electronics in them. I screwed on the side a 9V battery holder with an on\/off switch.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The schematic is pretty simple, with a single transistor, 2N5088. I didn’t have 2N5088 and I used a 2N2222 which is lower gain and higher noise; it works, but I plan to replace it with a 2N5088 on my next order. I’ll let you know the difference.<\/p>\n\n\n\n

I tried the schematic on a perfboard and added the tremolo using the Trigger Schmitt and the optocoupler but got a lot of switching noise from the CMOS oscilator. I should have handled the decoupling of the power supply better and probably the ground design, but excluded the tremolo part eventually.<\/p>\n\n\n\n

The components are not very demanding. You can use film capacitors.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The etched PCB didn’t look very well because I had a non-OEM toner in my printer and the ferric chloride went through it and attacked the copper.<\/p>\n\n\n\n

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You can find the the complete KiCAD project at the end of the post.<\/p>\n\n\n\n

Here’s the board mounted in the pedal:<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n
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KiCAD project: <\/p>\n\n\n\n

colorsound_wah<\/a>Download<\/a><\/div>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

Credits for the schematic to beavis audio research My son is playing the electric guitar, and I wanted to build an effect pedal for him rather than buy one. Many schematics are using inductors and are threfore harder to build because of this but I found a schematic that doesn’t need an inductor, the Optochopto: […]<\/p>\n","protected":false},"author":1,"featured_media":39,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[4],"tags":[],"class_list":["post-19","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-project"],"blocksy_meta":[],"jetpack_featured_media_url":"https:\/\/www.gearip.net\/wp-content\/uploads\/2026\/04\/IMG_3133.jpg","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.gearip.net\/index.php?rest_route=\/wp\/v2\/posts\/19","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.gearip.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.gearip.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.gearip.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.gearip.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=19"}],"version-history":[{"count":10,"href":"https:\/\/www.gearip.net\/index.php?rest_route=\/wp\/v2\/posts\/19\/revisions"}],"predecessor-version":[{"id":58,"href":"https:\/\/www.gearip.net\/index.php?rest_route=\/wp\/v2\/posts\/19\/revisions\/58"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.gearip.net\/index.php?rest_route=\/wp\/v2\/media\/39"}],"wp:attachment":[{"href":"https:\/\/www.gearip.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=19"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gearip.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=19"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gearip.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=19"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}