# Wave-Multiply-O-Matic v0.2 **URL:** \ **Category:** DIY STUFF\ **Created:** [September 19, 2021, 4:31pm UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010 "2021-09-19T16:31:45Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Jos](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jos/32/151_2.png) [@Jos](https://lookmumnocomputer.discourse.group/u/Jos)\ **Post date:** [September 19, 2021, 4:31pm UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/1 "2021-09-19T16:31:45Z")
## Sculpt-O-Sound presents Wave-Multiply-O-Matic v0.2 Wave-Multiply-O-Matic is based on Ken Stone’s take on a wavefolder design by Serge Tcherepnin. Here it is in the center of the picture (next to v0.1): ![20210919_172633](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/9/7/9788d4bc44dfc686bf0551f11d10bbb6f9dbeab6.jpeg) Because it consists of 3 types of Wave folders / VCAs the circuit needs quite a bit of space when implemented with thru hole components. So this meant that I ended up designing 3 PCBs, one for I/O and two for the wave folding circuits. ![20210915_225609](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/e/2/e2edc41f0dcf817a5e820757a3e1b32e5131c274.jpeg) ![20210915_225546](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/a/2/a2f7e533992a3c756a9171586deeea8dfab5b56d.jpeg) ![20210915_225557](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/7/a/7a16b8c29c28ae77a160e6c87dc3cce9b1dc169f.jpeg) The PCBs are stacked and interconnected using male/female pin headers which I cut to the length I needed, thus creating a sort of signal bus from pcb to pcb. The front panel is an aluminium type ‘pcb’, also ordered from JLCPCB. The switch caused the distance between the PCB and the front panel to be so large, that the potentiometers would not stick out of the front panel enough to hold the caps properly. Therefore I ended up using small stand offs which I glued to the bottom of the potentiometers to make them ‘taller’, so to speak. ![20210919_152837](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/0/0/0022c97483f1e1790ffa32e244adc16239557425.jpeg) Stacking PCBs this way is kinda neat, although it makes debugging a circuit difficult. I left the pins sticking out at the last PCB so that I could use dupont cables for measurements and debugging. ![20210917_180921](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/6/7/67de562e783533a864355bb4119f4d1a1c566cb2.jpeg) ---
**Author:** ![TimMJN](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/timmjn/32/15227_2.png) [@TimMJN](https://lookmumnocomputer.discourse.group/u/TimMJN)\ **Post date:** [September 19, 2021, 4:55pm UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/2 "2021-09-19T16:55:58Z")
Sweet build! That pcb layout is absolute mayham, which I love. Do you have any audio/video of it in action? And am I right to say that it’s eurorack? If it’s kosmo, I’ll gladly relieve you of some of those pesky surplus pcbs 😋 ---
**Author:** ![Jos](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jos/32/151_2.png) [@Jos](https://lookmumnocomputer.discourse.group/u/Jos)\ **Post date:** [September 19, 2021, 6:23pm UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/3 "2021-09-19T18:23:54Z")
Mayhem!? No, no, I don’t think so. How would you have done this? And yes, the build is eurorack format. ---
**Author:** ![TimMJN](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/timmjn/32/15227_2.png) [@TimMJN](https://lookmumnocomputer.discourse.group/u/TimMJN)\ **Post date:** [September 19, 2021, 6:36pm UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/4 "2021-09-19T18:36:45Z")
I’m mainly referring to the positioning of the parts. I usually start out with something like this, placing them according to the ratsnest. Then disable the ratsnest and clean everything up. But don’t take it as criticism, if it works it ain’t stupid haha ---
**Author:** ![Jos](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jos/32/151_2.png) [@Jos](https://lookmumnocomputer.discourse.group/u/Jos)\ **Post date:** [September 19, 2021, 6:50pm UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/5 "2021-09-19T18:50:13Z")
Ha, no offence taken! So far I’ve designed only a handful of PCBs, so there definitely is room for improvement. Also I didn’t have all the resistors I needed and had to resort to combining a few to approximate the values required. ---
**Author:** ![Jos](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jos/32/151_2.png) [@Jos](https://lookmumnocomputer.discourse.group/u/Jos)\ **Post date:** [September 19, 2021, 8:06pm UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/6 "2021-09-19T20:06:21Z")
I’ve posted a short video with some audio in July: > [@My build progress](https://lookmumnocomputer.discourse.group/t/my-build-progress/345/3420): > > I have been working on a wave multiplier, and made short demo video which includes the first prototype: [[Demo of Wave-Multiply-O-Matic] ](https://www.youtube.com/watch?v=4qvOS_Kq2kg) The recording is a bit noisy when signal levels are low. I suspect the BSP could be the culprit here. I’m struggling a bit with the configuration of the OTAs in the design. They appear to be quite sensitive to a DC offset of the differential inputs. ---
**Author:** ![Jos](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jos/32/151_2.png) [@Jos](https://lookmumnocomputer.discourse.group/u/Jos)\ **Post date:** [September 19, 2021, 8:23pm UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/7 "2021-09-19T20:23:46Z")
## Schematics ![top_section_wavemultiplier_v0.3_working_verified](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/7/c/7ceee320929beda8024e8a9a5dbdf857d345a28e.png) ![mid_section_wavemultiplier_v0.1_working_verified](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/c/3/c3eb28e5d3363594b40d6630f7ec067e62f83880.png) ![bottom_section_wavemultiplier_v0.2_working_verified](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/1/6/16e50addebe3fa8adfb07d0e6218cfef07b674f6.png) ---
**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:** [September 20, 2021, 7:18am UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/8 "2021-09-20T07:18:09Z")
That amount of 1M and 10M resistors could really add to the noisyness. The bottom section of the schematic is interesting, I have hard time grasping what actually happens in there. ---
**Author:** ![Jos](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jos/32/151_2.png) [@Jos](https://lookmumnocomputer.discourse.group/u/Jos)\ **Post date:** [September 20, 2021, 5:46pm UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/9 "2021-09-20T17:46:03Z")
> [@Krakenpine](#): > > That amount of 1M and 10M resistors could really add to the noisyness. Yes they do. And the same goes for the use of the OTAs that are meant to process tens of milli volts. ---
**Author:** ![Farabide](https://avatars.discourse-cdn.com/v4/letter/f/ecc23a/32.png) [@Farabide](https://lookmumnocomputer.discourse.group/u/Farabide)\ **Post date:** [September 24, 2021, 6:58am UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/10 "2021-09-24T06:58:25Z")
“O-matic presents” and already smiling. Great work @Jos ! ---
**Author:** ![Jos](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jos/32/151_2.png) [@Jos](https://lookmumnocomputer.discourse.group/u/Jos)\ **Post date:** [July 1, 2024, 10:21am UTC](https://lookmumnocomputer.discourse.group/t/wave-multiply-o-matic-v0-2/4010/11 "2024-07-01T10:21:38Z")
Oh, oh, oh, when revisiting this post I saw that I have not included the schematics that include the pots and connectors on the front panel. If anyone needs them, let me know.