What's your nemesis circuit?

thomasbe86 said:
I love you guys but I do feel a little better knowing I am not alone :)


It is a mid thing, like MF1 of the Amek Mozart MZ15-RN, just keep making silly mistakes like powering it up with 18v with 6.3v rated caps was the last straw today...

WLCSP is way to small for my aging eyes, any good experience with these?
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No, just wondered because I'm fascinated by them. Maybe just because they're a shiny and (relatively) new package?

Haha, yeah working with low voltage stuff can be "fun".
 
I started building stompboxes in 2020, so i didn't have time to create a real Nemesis yet.

Worst cases so far are :

- Aion's Neurotron (Lovetone Ring Stinger), a big ring modulator circuit. One of the 4 waveforms wasn't working correctly.
I tried my best to find the issue but it was really tidious to put the circuit in and out of the box with 6 jacks, 6 pots, 2 rotary switches and 1 toggleswitch. One look at the schematics and i knew i'd never get out of this troubleshooting attempt.
After several attempts i had suspicions on the rotary switches sub boards connections to the main board, but nothing for sure.
I used components legs instead of short wires to make it easier to fit in the box, and more sturdy.
Sub boards and the main board were too close from each other to allow me to visualy check what was going on there.
Continuity tests couldn't help me much because with such a complex circuit i wasn't able to properly follow the schematics and point the corresponding locations on my build.
One day, 1 year later, i just desperately rewired both rotary switches without much expectations, and the faulty waveform suddenly worked.

- Lectric FX Flintlock (A/DA Flanger), my favorite flanger. I built 2 of them, both are doing whistling noises at some settings, but they can be silent if i can find the right spot in the signal chain.
Removing the LT1054 and using a 18v power supply seemed to help a bit, but i think it also depends on the electrical environement, other circuits around it, etc
I wish i could find a way to completely remove the whistling noises to be able to fully enjoy all the settings, no matter the circuit position in the signal chain, but i'm not sure it's even possible.
One day i tried to build some kind of shield around the power section, hoping to prevent some interference with the circuit and remove the noises.
After a while i noticed a weird smell, i opened the box and saw the LT1054 melting on the pcb, on my favorite flanger...
The shield was probably shorting two pads, or it was preventing some heat dispersion or something.
I managed to make it work again, but i ordered and built a second Flintlock circuit because i really appreciate this flanger, same whistling noises on the second build, depending on settings and location in the signal chain.
The burnt smell is still lingering in the enclosure, 3 years later... it's subtle but it's there.
I think the burnt Flintlock circuit sounds slightly warmer than the newest one, but that's surely my imagination.
 
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lectric-fx Dandy Horse. Built one on commission and used my fee to purchase 2 of everything.
The first one (after WEEKS of troubleshooting) somehow got calibrated and working. Super interesting pedal but simply not worth the effort or the $200+ in parts, especially since I don't have an oscilloscope for proper fine tuning.
The second one just never got going. Something to do with the power section that takes 9v, charge pump to 18v, then regulates it to 15v and distributes all sorts of other voltages from there. After the shit fight with the first one, I never had the energy to fully troubleshoot it. I might fiddle around with it in a year or two to see if I can make it work, but I'll certainly never build another.
 
I seem to remember it taking us about 6 or 7 prototypes and over a year to get the DandyHorse PCB working reasonably and I recently "redesigned" the MN3007 Echo Flanger for PastFX with every improvement I could think of, comparing it directly to original units and using all I had learned in the 10 years in between to make both building easier and end results sound closer to the original while allowing compensation for its flaws.

And even on pre-assembled SMD boards, it still gave more trouble than far more complicated effects to get it working nicely.

Coincidentally, every original I repaired over the years has varied in its own idiosyncrasies... I did repair a couple of perfect units, but there was zero difference between them and the ones that would tick or chirp or just sound a bit wimpy even after re-caps and re-biasing.

It is a cursed circuit... or could just do with redesigning from the ground up really.
Obviously the reissue attempted that, but I think it strayed too far from the original.
 
Scruffie said:
I seem to remember it taking us about 6 or 7 prototypes and over a year to get the DandyHorse PCB working reasonably and I recently "redesigned" the MN3007 Echo Flanger for PastFX with every improvement I could think of, comparing it directly to original units and using all I had learned in the 10 years in between to make both building easier and end results sound closer to the original while allowing compensation for its flaws.

And even on pre-assembled SMD boards, it still gave more trouble than far more complicated effects to get it working nicely.

Coincidentally, every original I repaired over the years has varied in its own idiosyncrasies... I did repair a couple of perfect units, but there was zero difference between them and the ones that would tick or chirp or just sound a bit wimpy even after re-caps and re-biasing.

It is a cursed circuit... or could just do with redesigning from the ground up really.
Obviously the reissue attempted that, but I think it strayed too far from the original.
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Scruffy!!!! Great to see you man. Look at you sneaking back in like you been here the whole time.
 
Aleph Null said:
Anything with an OTA in it. I can't get an OTA to make any sound. I've built other people's designs with success, but none of my ideas pass signal.
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This. OTAs are the devil incarnate. One minute they pass sound, the other dead silent. Check connections, rebuild, nope, nada, rien, null.

Also, the (original) TS9 sitting on my shelf. I have disassembled it three times, voltages - check, solder points - check, transistors, check, plug in guitar - yup, works as it should. Reassemble, plug in guitar, again works as it should for two minutes, then craps out and sounds broken. Too lazy and too proud to shotgun it, so I use my Arion Tubulator instead :ROFLMAO:
 
Scruffie said:
I seem to remember it taking us about 6 or 7 prototypes and over a year to get the DandyHorse PCB working reasonably and I recently "redesigned" the MN3007 Echo Flanger for PastFX with every improvement I could think of, comparing it directly to original units and using all I had learned in the 10 years in between to make both building easier and end results sound closer to the original while allowing compensation for its flaws.

And even on pre-assembled SMD boards, it still gave more trouble than far more complicated effects to get it working nicely.

Coincidentally, every original I repaired over the years has varied in its own idiosyncrasies... I did repair a couple of perfect units, but there was zero difference between them and the ones that would tick or chirp or just sound a bit wimpy even after re-caps and re-biasing.

It is a cursed circuit... or could just do with redesigning from the ground up really.
Obviously the reissue attempted that, but I think it strayed too far from the original.
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Oh! Mr. Lectric-FX? Thank you for your work. Yours have been rmy favorite pcbs to build yet; you make large circuits fun to put together. Only if Aion would drop their daughterboards, would you see competition. :)
 
Blackboarcult said:
This. OTAs are the devil incarnate. One minute they pass sound, the other dead silent. Check connections, rebuild, nope, nada, rien, null.

Also, the (original) TS9 sitting on my shelf. I have disassembled it three times, voltages - check, solder points - check, transistors, check, plug in guitar - yup, works as it should. Reassemble, plug in guitar, again works as it should for two minutes, then craps out and sounds broken. Too lazy and too proud to shotgun it, so I use my Arion Tubulator instead :ROFLMAO:
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Tube screamer was my first ever attempt, and second, and third,...
Back in around 2004, a friend and I spent about 8 hours to put one together on vero board.. so excited to test the result, plugged it in, no sound, started to smoke here and there.. Had forgotten to clip the leads of every single component shorting each other in the back... Still took us a while to figure out what we did wrong 😅
 
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