The LEDs are in the feedback loop, so if one is stuck on you have a DC bias there. Which could mean that your 470 nF is bad, the resonance potentiometer is wired up wrong, or the filter is plugged into something that messes with the output signal. Does it stay on also if you unplug the output?
What transistors are you using?
Have you checked that all IC pins are properly seated?
Thanks for the advice fredrik:
ICs fully seated on a visual check and oriented properly with the half circle ādownā - will be taking the front panel off a little later today to double check the solder on the IC sockets and reflow everything
Transistors are BC558 - BK825 is the printed below that
Right side LED lights as soon as the module is plugged into power source, before plugging in any jack sockets
470 nf cap looks properly soldered in - could try swapping it out for a spare
Not sure how I would have soldered the resonance pot in wrong but Iāll reflow the solder to be sure
I do have a simple multimeter, but Iām pretty new to all this so Iām not sure how to use it to track down the problem.
@fredrik - you absolute legend. I just reflowed all the solder and replaced the 470 nf cap and it seems to be working properly! Thanks a ton for your help!
Now need to go get some plywood and build a case!
Hello,
I canāt get it work because i burn some holes and then desoldering make it burn some more holes
Anyway now i have a full voice kosmo working except the performance filter and i just have the panel for it now.
my question is, how to have the same pcb now? because on the website i donāt realy mind to order a new one, i will get an extra panel but now they are sold out.
So, is their a way for me to order a pcb from an pcb printer website something like that ? And how i can do it? (im in EU)
i have seen something like this :
how can i get a file that is the same of the pcb performance filter ?
First ask @lookmumnocomputer if heās going to restock. Heās said it wonāt be restocked but will be replaced with a new design, but I havenāt heard anything about a new design actually being ready, so I wouldnāt be very surprised if he did restock.
If notā¦ he hasnāt typically made Gerber files for his boards available, but maybe for one heās no longer selling heād be willing? Could ask.
I have some if you want to send me an email. I can send the pcb only. lookmumnocomputer at. geeeeemmmaaaaiiilllllll dot codmmmmmmm
as in just pcb not panel. I hadnāt realised they went out of stock! oops
Never quite got mine to work right, it just seems to self oscillate and not do anything with the inputā¦ Keep putting it to one sideā¦
Hi, anyone has the schematic please? I see a lot of difference between lmnc and schmitzbits (for an example, the amount of 10k resistors, the switch etc).
Thx in advance (from a beginner )
Hi Mattheewww , schematic of what ?
Schematic of the performance filter. I see a lot of differences between lmnc pcb and schmitzbits schematic. Fredrik seems to have a good one. I want to scale it to eurorack but Iām kinda new in electronics, I only do pcb from schematicsā¦
@fredrik if you read this 
yeah the schmitzbits is the schematic Sam links to , not sure if there is an other based on Samās exact pcb.
So dont buy the one now? and wait for the new version ? Or are we good ? Love these projects, if we could just find the mega ducker .
Gotta catch them allā¦ 
here is the schematic!
As for the newer filter its not super similar to this one. is rather funky, more of its gnarly sibling thatās a bit skittish. both quite different even though using lm13700ās 
I have Samās Kosmo setup as my video chat backgroud at work. I had to clarify that it was indeed āmega DUCKā, and what that means.
One day, my modular will be big enough to validate throwing it up there instead.
I was looking one day thru his you tube videos and it popped up, 4 relays and some 2n3904 as triggers and spdt to go from one jack to 2 jacks and reverse and even adding piezos . He called it megaducker as in the process of radio āduckingā certain audio content in and lower and out completely .
I havenāt let that hold me back:
Though I do patch it up to blink as many lights as possible rather than sound good so itās a more interesting background 
If I can fill a few more cases for that big empty spot over my left shoulderā¦even better 
Hi All,
I am looking for some assistance; I recently built the performance filter,
But I am not convinced it is working correctly.
The res filter does not seem to affect the sound, and the filter does not appear to be filtering; it just seems to turn down the volume, it does not seem to get filter sweep.
Steps I have gone through to diagnose
Reflowed all the solder points
Swapped out the chips
Checked for shorts
Checked values on components
Checked the voltage coming in
and taken reading from the chips
I am hoping someone can give me some pointer or ideas of what is wrong.
I have included some oscilloscope reading to help, sorry for all the pictures
Thanks in Advance
TL074 PIN 6 -11.6V
TL074 PIN 11 11.56
LM13 PIN 4 12V
LM13 PIN 11 -12
Source Reading
