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Topics - Jebus

General Questions / Drolo MDD programming issues
February 09, 2023, 06:06:37 AM
Hello everyone!

Long time since last post and almost equally long since last finished build. Finally getting back to this great hoppy: just finished building Drolo's Molecular Disruption Device. This is version 1.1 which PCB I bought waaay back. Stock build, but added switch to try out the internal programs on the Spin FV-1. Those work really well and sound surprisingly good.

However the issues started when I tried bunch of external patches. I have downloaded lot of patches online and also created some with SpinCAD. Almost all of the patches I have downloaded or created only output clean signal or no signal at all. For example from this huge library I have tried maybe half already and the only working one is the Improved Octave Up:

I created simple proof-of-concept volume control effect on SpinCAD:

and the code:

;------ Input
;------ Pot 0
;------ Volume
RDAX ADCL,1.0000000000
WRAX REG0,0.0000000000
;------ Output
RDAX REG0,1.0000000000
WRAX DACL,0.0000000000

This works just as expected. However if I do anything else in SpinCad it wont work. For example simple reverb with the same setup:

And the code:

; ----------------------------
;------ Input
;------ Pot 0
;------ Minimum reverb
RDAX ADCL,0.2500000000
RDA 122,0.325
WRAP 0,-1.0
RDA 426,0.325
WRAP 123,-1.0
RDA 980,0.325
WRAP 427,-1.0
RDA 1903,0.325
WRAP 981,-1.0
WRAX REG0,1.0000000000
RDA 21990,1.0
RDA 5727,-0.325
WRAP 1904,0.325
WRA 5728,1.99
RDAX REG0,1.0000000000
RDA 12240,1.0
RDA 16973,-0.325
WRAP 12241,0.325
WRA 16974,1.99
WRAX REG1,0.0000000000
;------ Output
RDAX REG1,1.0000000000
WRAX DACL,0.0000000000

This only outputs dry signal, no reverb. What am I doing wrong? Is there some setting I'm missing or something? The same happens with all other effects I've tried from SpinCad (OD, fuzz, reverb, delay, flanger etc). I'm not yet familiar enough with the code itself to figure if there's some error, but I think SpinCAD has been used for quite some time with lot of folks.. Or could there be something wrong with the FV-1 chip? This version of MDD is pretty much the same as the concept schematic from FV-1 datasheet. Just added dry/wet blend and feedback loop from right channel output to right channel input. I've tried different effect slots and all have the same result.

I'm using SpinCad 1032, newest SpinASM and PicKit 2. Looks like Drolo has removed the build docs from internet, so out of respect to him I'm not sharing it at least on this point.  ;D

Cheers, Kalle
How Do I? Beginner's Paradise. / Help with first layout
January 23, 2017, 11:01:14 AM

I got access to CNC PCB mill and lots of cheap material. It can do single sided PCBs (drills holes and everything). So, I just did my first layout for Big Muff with Eagle.

So, even I think it looks messy. ;D I tried to move parts around and redo connections, but that's pretty much best I could on first try. It's going in a 1590BB, so there's lots of room. I tried to put the parts bit more apart to make soldering more easy (no solder mask).

So, could someone more experienced take a look and let me know what immediate problems are there? Will the long connections (for example C2 to C4, C8 to C6 or volume pot to out) cause problems?

Lots of people seem to use 45 degree angles instead of 90 degrees. I've always thought this doesn't matter in audio frequencies (only higher). Does it?

Any other tips or advice?


Edit. One more question: what are those blue patches at bottom right, below volume pot and at top right corner?
Build Reports / Doppelbanger
August 05, 2016, 09:54:07 AM
Super late for the party, but here's my Doppelganger build I finished yesterday. I ordered PCB well over year ago, friend of mine draw the graphics (and titled it DoppelBanger) last winter and I finished the wiring yesterday. The texts got all messy because first paint marker I used didn't like the clear coat. Live and learn.

Went straight to my pedal board. :)


Edit. Fixed the photos
Tech Help - Projects Page / Rust Bucket debugging
May 12, 2016, 09:59:44 AM

I just finished my Rust Bucket. I don't get any effected output. Blend works.

Took out my audio probe and started to mess with it. MN3007 outputs effected signal. Junction of R28, R29 and R30 has signal. Nothing can be heard at pin 2, 3 or 6 of IC11 or after that. So, I assume that the problem lays in that area.

I have checked all the values of components around IC11 and they seem to be good (except I have 33n in C17 instead of 27n).

Supply 17,85V

IC11 (CA3080)
1 0
2 0
3 0
4 -14,74
5 -14,74
6 0
7 15,14
8 0,01

IC12 (LM741)
1 -14,72
2 0
3 0
4 -14,73
5 -14,72
6 0
7 15,13
8 0,01

When I compare my voltages to ones in the build document I notice that there is supposed to be small voltages where there are zeros on my measurements. I tried to measure them with the most accurate setting of my DMM (200mV area), but I cant get any good readings. Maybe my cheapo multimeter just can't handle that low voltages.

All ICs have sockets.

Any ideas how to go from here? I'll post some pictures later.
Audio/Video Demos / Total Recall
May 04, 2016, 03:15:12 PM
Already linked to the build report, but here's a demo of my Total Recall build:

Build Reports / Total Recall
April 11, 2016, 05:02:41 AM

Its been some time since I've finished last pedal and made a build report. This spring has been really hectic. Well, today I got something ready! Here's my build of the Total Recall build on one of the prototype boards. I've been really slowly building it for almost five months, but finally today got it all wired up and ready. I still need to tweak the bias, but it already sounds wonderful!

Tall 1590BB, sticker paper and envirotex. I bought the knobs originally for Arcadiator, but I didn't like them on that. Led is hidden under the graphics. When I was mounting the led I think I accidentally pressed it bit too hard against the Envirotex. You can see the light making weird pattern where the Envirotex is bit lifted. Fortunately you cant really see it unless you look the pedal closely from side against light.

I'm using two Xvive MN3005. Originally was supposed to go with 4xMN3008, but when I got these I didn't feel like using the old ones. :P
Tech Help - Projects Page / Total Recall voltages
April 07, 2016, 04:55:22 AM

I finally got my Total Recall wired up and I'm bit confused with the voltages. I'm using the recommended EHX power supply. It reads about -31V (no load). I plugged it in and measured the voltage output from the LM7915 and it reads -18,3V. That feels way too high to me, but I cant figure out whats wrong.

Input of the regulator is about -29,6V and the regulator is grounded properly. Only thing I can think of is a bad regulator, but I don't have another one to test with. Any other ideas? :-\

I'm building a Rust Bucket and somehow I don't have 18 nF (C6) and 27 nF (C17) capacitors. Can I use any other values in place of those? I got 15nF, 22nF and 33nF. I guess they would work, but I'm not sure is it better to increase or decrease the capacitance on those spots.

Here's the build document:

Build Reports / 2015 all over again
January 19, 2016, 12:39:36 AM
I wan't to do one of these threads too. ;D Going from newest to oldest (I think):

Opamp Muff


Krypton Phasor

BeeBaa & Orphan Fuzz

Feta Complis



Kingslayer II & Purple Plexi

I'm pretty sure I'm missing one build from that list, but can't figure out what it is. :D
Build Reports / Dual overdrive and Afterlife
May 11, 2015, 07:08:54 AM

Here's my latest two builds.

Dual overdrive in 1590BB. On right there's a Kingslayer II and on left a Lovepedal Purple Plexi (thanks cooder for the board!  :) ). Both are stock builds. There's a switch to reverse the order on top left. My fiancee wanted to draw something to a pedal that I've built, so she made the graphics.  :)

Also built Madbean Afterlife which is my first 1590A build ever. Probably also the last..  :D I think the box looks really good. I painted it red and soaked it into red/gold glitter. Its way more glittery in real life than in this photo.

Also labeled the second pot as "C" like compression, not S for sustain like it should be.. D'oh.

No gutshots, I'm too scared to open the Afterlife anymore and the dual overdrive isn't that good looking from inside.  ;D
Build Reports / Two Kingslayers
April 22, 2015, 03:33:10 AM
Built two Kingslayer 2s for friends.

These we're probably the tightest builds I've done so far. I decided to save couple of euros per pedal and bought cheaper knock offs, not genuine Hammond enclosures. That was a huge mistake. They we're supposed to be exact same size, but instead they are just a bit smaller and rounder on the edges. In order to make them fit I had to superglue the DC jacks in place.  :(

Still very happy that both worked on first try.  :)
General Questions / Wah doesn't wah
March 04, 2015, 01:02:58 PM

Little bit of backstory first: when I first got into pedal building in 2005 I ordered bunch of boards from a guy here in Finland. He etched these himself and they we're really cheap. Also the quality was a bit cheap. So, one of the boards I ordered was a Vox V847 -wah-wah replica from GeneralGuitarGadgets. I never got it to work (only bypass worked, no sound when it was on) and after some testing I just gave up.

A month back I found the board and decided to make it work. I re-wired everything and put it into a Crybaby enclosure. Hooked it up and it still doesn't work. Previously there was no sound, no there's sound but no effect. It basicly sounds like a wah that is left to "middle" position (=little bit of lows and highs are cut). The potentiometer doesn't seem to do anything.

Had to use Internet Archive to found these pictures, but here is the schematic and layout I used (thou I did the switch differently - so that the pcb input is grounded when its bypassed):

And here's couple pictures of my build:

And here's the voltages of the transistors:

C 4,14 V
B 0,69 V
E 0,12 V

C 9,03 V
B 3,72 V
E 3,29 V

I have triple checked all the capacitor and resistor values. They seem correct to me. I didn't have any MPSA18s so the transistors are BC550Cs.

Any ideas? This is currently driving me nuts.  :D

Edit. I just realized that those pictures are not that good (noisy). I'll take better ones tomorrow in daylight.
General Questions / Kingslayer II capacitor question
February 26, 2015, 10:44:49 AM

I started to build two Kingslayers yesterday. Now all resistors and most of the caps are in their place, but I have little bit of shortage of some capacitors. I only have 1uF tantalums, nothing else. So, can I use those instead of film ones mentioned in BOM (C3, C11, C12, C17)? Which way should I put them in? I assume C11, C12 and C17 are there to block DC-current and C3 and the resistors R3 and R4 forms some kind of HP-filter for negative feedback?

My instinct says C11, C12 and C17 positive towards the op amps and C3 towards the input, but I dont trust myself enough..  :D

Edit. Heres the link to the documentation:
Build Reports / First two Madbean -builds
January 30, 2015, 03:06:04 AM

Got my first two Madbean -builds ready.


Basic build, nothing special here. First time I ever used decal. Turned out pretty good.

Zero Point Mini with little bit of modifications:

Added footswitch for ring and a potentiometer to modify the feedback resistor. It can go from very neutral delay to oscillating weirdness. You can also plug in a expression pedal to control the feedback, haven't tried that out yet. This one is built to a EHX Enigma Q-balls -enclosure, first time ever there was plenty of room inside..

No gutshots, these didn't turn out so pretty.