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It's pitty, that it doesn't work. I guess, that bad pcb is now most suspectable. Try to measure cunductivity of it. Use multimeter at this function (diode glyph), and measure all tracks from point to point.

First and foremost, I'm sorry for taking three months to reply to you...
I tried measuring the traces/tracks way back when I (we) tried to find the problem with the circuit, but alas, no luck. I decided to replace the PCB with a PCB Guitar Mania Kloned Centaur PCB. Even though it only has a voltage swing of 18v (+9v and -9v) I really like the sound of it I'll salvage the old Sunking PCB for parts probably someday...

Thank you for all the help and patience!

Wow, that's all kinds of awesome!  Great build.

I'd be interested to hear the square wave LFO.  Since it never passes through the origin, I wonder if it ever sounds in tune?   Maybe at faster speeds?

I've recorded a demo showcasing the square, ramp up and ramp down waveforms. Later in the sample, I "distort" the waveform using the "Deform" control on the pedal. This control basically alters the dutycycle of the selected waveform. I found that on ramp up/down, altering the dutycycle can make the "gliding" of the vibrato more apparent (best heard around 0:55 onward).
Anyway, I've found the most useful waveforms to be either the sineoid, triangle and lump/valley waveforms (or the variations thereof). The various possible waveforms can be seen on page 3 of the TAPLFO pdf.

[soundcloud]https://soundcloud.com/user-584389416/cv19demosquareandrampwaves[/soundcloud]

0:00-0:04 - clean
0:04-0:33 - square 40% mix and 100% mix
0:33-0:55 - ramp down 40% mix and 100% mix
0:55-1:25 - ramp up 40% mix and 100% mix

That's phenomenal! Love it, man. I might try that with something I built.

Thank you very much! What effect are you going to try it with?

Nice build, great graphic too!

Would you classify this effect to be a good clean booster too, and is it a bit transparent? I bet putting a voltage doubler on it to give it ~18ish volts would be interesting

Thanks guys! I'm glad to hear ya'll like it

I'd be interested to hear the square wave LFO.  Since it never passes through the origin, I wonder if it ever sounds in tune?   Maybe at faster speeds?

Hmmm interesting question! If you like, I can record a demo using all the non-sine/triangle waveforms

Howdy folks!
Long time lurker here. I finally built something I thought was noteworthy and/or impressive enough to share. I did build a couple other pedals over the years but I might post those in a seperate thread later.

DISCLAIMER: the name of the pedal is by no means meant harmfully, offensively or in a jesting manner. It is a nod towards COVID-19 though, because I built/developed most of it during the quarantine of 2020 and it was one hell of a release from cabin-fever at times. Inspired by the ZVEX Lo-Fi Junky, I dreamed up the idea of a BBD Chorus/Vibrato unit controlled by the TAPLFO v3 chip in late '19.

After studying the TAPLFO chip's inner workings and required circuitry, I adapted it to feed a Madbean Porkbarrel (2019 version). According to electrosmash the LFO of the regular old Boss CE-2 puts out between 2~7ish volts, so I figured I could utilize the circuit displayed on one of the last pages of the TAPLFO pdf. I drew up my own schematic (see below) for easy reference, made a layout and tested it on the scope. I can say the layout (see below as well) I made is definitely verified, although it can probably be improved upon in terms of space and/or component placement.

Anyway, I simply tied the depth pot's number 3 lug to the Porkbarrel's Depth number 2 pad hoping it would work straight away - and it did! The MN3101 accepts all waveforms! The sawtooth and squarewaves sound a bit janky though, but that may also be because I still have to swap the LFO amp's IC out for a TL061 (for lower power consumption), or maybe it's just a feature/sound of the BBD's clock frequency suddenly being shifted dramatically. I don't have enough knowledge about BBD's to know what's causing this.

Another issue is the depth pot. It's a 100kB and it seems to have all of it's "depth" tweakability bunched up near the end of it's travel. I figure I'd have to swap it out for a lower value and a different taper. I guess a 10kA would work. The wiring could've been done better in terms of neatness, but it's not noisy and sounds crystal clear, so I guess it's fine the way it is.

I also decided to omit the Speed multiplier rotary switch (labeled "RSW2 Multiplier" on my schematic) because I figured I'd mostly be using the speed pot by itself.

Anyway, I'm super proud of this build. It fired up straight away the first time I powered it on and I'm REALLY happy with the sound of it. It's got everything from subtle vibrato to the weirdest chorus effect one can think of. Also very applicable to synths I think... it can get very deep and lush on the highest depth settings, and a bit reminiscent of a flanger on the lower depth settings.

Enough of my rambling, here are some photos! Sound demos can be found below as well. I've added some timestamps to indicate what settings were used.
The sound demos were recorded using Amplitube and a Fender Player series Jaguar.








Gut shot! The two small trimmers on the back of the speed pot were added to dial in the range of the pot. I'm glad I put those in there, because they were definitely needed to give the control a manageable range.


Schematic. Apologies for my handwriting.


The TAPLFO layout I cooked up.

[soundcloud]https://soundcloud.com/user-584389416/cv19demonoreverb[/soundcloud]
(please forgive my butchering of the first two songs)
0:00-0:09 - clean
0:10-1:04 - triangle mode, medium depth, medium rate 35% mix
1:05-1:38 - sine mode, medium depth, medium rate, 35% mix
1:38-2:02 - sine mode, medium depth, medium rate, 100% mix
2:02-2:16 - sine mode, more depth, more speed, 100% mix
2:16-2:46 - sine mode alternate waveform, medium depth, medium speed, 40%ish mix
2:46-2:57 - sine mode alternate waveform, max depth, medium speed, 40%ish mix
2:57-3:05 - triangle mode alternate waveform, max depth, medium speed, 40%ish mix
3:05-3:34 - sine mode alternate waveform, max depth, more speed, 100% mix

[soundcloud]https://soundcloud.com/user-584389416/cv19demodrenchedinverb[/soundcloud]
0:00-0:14 - clean
0:14-0:36 - sine mode, medium depth, medium rate, 40%ish mix
0:36-0:45 - sine mode, medium depth, medium rate, 80%ish mix
0:45-1:47 - sine mode, maximum depth, medium rate, 100% mix
1:47-2:15 - sine mode, maximum depth, medium rate, 40%ish mix


Thanks for reading and listening! I hope you enjoyed

First off, I'm sorry for taking so long to reply. Life got in the way haha.

Alas, that solution did not help either. I don't know what's up with it, maybe there's an issue with the PCB somewhere which I can't find... very strange. I think I'll just order a different PCB and try again. Thanks a lot for trying to help me

You have a good point! It is indeed really strange.

I measured the pins while the opamp was out of the socket, and I see slightly lower voltages on pin 6 and 7 than when it is in the socket! This is strange as well to me 
These are the measurements I made:
Gain pot fully CCW
IC1_B pin 6: 4,50 volts
IC1_B pin 7: 4,31 volts

Gain pot fully CW
IC1_B pin 6: 4,54 volts
IC1_B pin 7: 4,36 volts

Still no shorts or links to ground where they shouldn't be though...

Last thing I can offer is to measure if pins put in socket have the same values as nodes, where they are connected around. Continuity in circuit with socket. Now I am really wonder, what shit will be there engaged.

What do you mean exactly? Should I measure from the pins of the socket without the IC in it directly to the nodes to check if the values are correct and if there are no shorts? Or should I check with the IC in the socket? I measured from the pins of the IC, while the IC was in the socket... so I would think that if I measure it that way the socket is tested for faults too...

Moving Gain pot at the min. position will almost wipe away signal at the input of IC 1B. It is normal.

4.5V potentials at IC1B is not a problem. Maybe I would wait slightly less voltage at pin 6 of IC 1B. But finally it will be some mechanical issue, I guess. Crackle of pcb track around IC1, bad socket....

If straight connect of resistors with VB doesn't make gain jump, something is wrong here. Maybe shortage at output? Here is capacitor C10. Measure it, if it is not kicked thru. After it, controll, if switch bypass BYP_B is not bad, to ground output signal.

I have checked the socket, socket is good because I measure directly from the IC pins to the corresponding resistor pins (skipping the traces, to test continuity). Also checked on high ohm setting to check if the resistors are the correct values and making good contact, for example measuring between IC1_B pin 7 and R7/R8/C7 node. I have checked everything around IC1_B this way for shorts, continuity, values, etc.
C10 is not broken, it measures a good 1.1uF. I also checked BYP_B to check if it's not switching to ground when the effect is engaged. I measure no connection between R10/C11 node and ground when the pedal is "ON".

EDIT:

I even checked if the signal is reaching IC1_B, which is the case. Checked with audioprobe and the signal arrives at IC1_B pin 5. Continuity between IC1_A pin 1 and all components until IC1_B pin 5 is good, too. No shorts, correct values etc... I don't know where to look anymore

Alright let me re-assess something here: I am getting 4.55v (VR) on ALL lugs of the Gain pot regardless of it's orientation... is this normal? It appears to connect to all the points it should connect to, without any shorts - I measured continuity to be sure.
I'm getting signal on pin 7 of IC1_B, but it's very weak and not very gainy at all (regardless of orientation of the Gain pot).
When turning the Gain pot the tone goes from bright to dark, around the midpoint there's a slight volume drop. I'm guessing something is awfully messed up with the pot (yet when desoldered it measures properly to it's intended value). Also on Gain B I measure 1.5ish K between the wiper and either 1 or 3, when pot is turned to either extreme. I guess this is normal because there's a 1.5k (R4) in parallel over lugs 1 and 3 of the pot.

I just did another hour of checking and testing and I'm stumped. Maybe I'll just order a pedalpcb kliché and rebuild it, I'm getting tired of chasing a ghost

It will be some stupidity, mark my words :@)Power for IC, bad socket or so... Maybe crack in PCB track. Measure those tracks around that place.

Yeah, it probably is something stupid that I'm missing :') I'll give it another whirl today. Power for IC's is good tho', measured that before I measured anything else. Voltages are good, see OP.

Check your diode orientation and make sure the switch wires are connected to the correct lugs. The pads for the switch also look like they could stand to have some more solder.

Diode orientation is good, I did check that before. They are opposite eachother in direction. Also, when the clipping switch is in the middle (in the OFF position) the pedal should oscillate/whine at the highest gain setting, yet it doesn't. Continuity is good between pads and switch.

EDIT:

It seems to me continuity should be bad (or there's a short) somewhere between pin 7 of IC1_B and pin 5 and 6 of IC1_B, just like Zerro said. I just can't seem to figure out where the problem lies.
Everything else in the circuit works properly, because the tonal shift I hear when turning the gain pot is logical - the filters at R12-R14 are responsible for that I preasume. Volume and tone pot work fine too.

Gain for IC1_B is defined now by ratio of R7/R8. This must be now cca 28. This is high gain. So, or R7 is wrong, showing low resistance, or R8 is corrupted, showing high resistance. OR, C9 has shortaghe, so signal is not going thru R7. Those 3 details are now suspicious. If measurements will show they are ok, then replace IC1.

I checked R7, it's aroundabout 428k. R8 is a solid 15k. C9 is not shorted, I measured across it's legs and it's got no continuity - I measure 428k but that's because R7 is in parallel with C9. I tried swapping IC1 over with IC2, no change. I tried swapping IC1 with a MC1458P I had laying around (which is essentially a dual opamp), no change...

Alas, no change when I apply VR to the point you specified at the R9/R8 junction. I've also reflowed everything between IC1_B pin 7, R7, C7, R8, R9 and also measured continuity, but everything looks good. I also measured continuity between the wires of my gain pot to check if one of them isn't broken, but it's all fine. I also reflowed all the pins of the IC socket of IC1_B.
I still receive the same sounds as I described before, this is really strange...

Hi guys, first of all thanks for your replies! I'm sorry I took so long to get back, some stuff came up and I had to deal with it.

I get VR (which is 4.55 volts) at all pins of the pot, regardless of orientation. I did also desolder the pot before and checked if it didn't have any shorts and if the value is correct when I rotate the pot to it's extremes. I scratched the parts you mentioned to clear off some flux and dirt, but this didn't produce any results unfortunately.

There's something else that's a bit strange, which I forgot to mention in the first post: when I rotate the gain fully CCW, the pedal gets really bright, when it's at center the pedal sounds almost clean, when the gain is fully CW it sounds a bit darker with a tiny bit more gain than unity.