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DIY Stompboxes => Building your own stompbox => Topic started by: FUZZZZzzzz on January 09, 2019, 02:01:26 PM

Title: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on January 09, 2019, 02:01:26 PM
Hi guys!

It's been a while since I've posted. I just finished a new pedal that I've been working on and decided to share it with you guys. It's a very simple design with only a few parts. If you want to change the sound of the filter you can change the diode and value of the 4,7 nf cap. I prefer both the 2,2 nf and 4,7 nf on a switch. The 1n4148 give the most clean result. The 10k pot tames the filter intensity. You can abandon it completely if you like mayhem. I can create synth like tones (play with the 4,7 nf cap) and even some funky stuff.

The enclosure is tiny. Was a real adventure to make it fit. Enjoy!

(https://i.postimg.cc/4d9hshWR/filterrrr.jpg)




Title: Re: I've designed a Filter Pedal for Bass
Post by: deadastronaut on January 11, 2019, 08:00:08 AM
brilliant, great simple design..nice work man, sounds great... 8)



Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on January 14, 2019, 03:35:33 PM
thanks! i'm indeed very happy with it. it's also very quiet when you're not playing.
Title: Re: I've designed a Filter Pedal for Bass
Post by: rankot on January 14, 2019, 05:20:46 PM
How does it work?
Title: Re: I've designed a Filter Pedal for Bass
Post by: ElectricDruid on January 14, 2019, 05:59:35 PM
It looks like a synced oscillator circuit. If I was feeling pedantic, I'd have to argue with the description of the circuit as a "filter", but luckily I'm not feeling pedantic so I can just let it go and sit over here and do some breathing exercises...breathe....breathe...breathe...;)
Title: Re: I've designed a Filter Pedal for Bass
Post by: Rob Strand on January 14, 2019, 06:13:38 PM
Extremely cool design.  I was playing around EQ'ing the output and there's a lot of sounds in there.

Where did you get the idea for diode and 4n7?   It's not a normal thing to do.

I heard this track a few months back (Synthy bass comes in a 0:30).   I wonder if your circuit can help get that sound.
https://www.youtube.com/watch?v=boLGFfnCZDg
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on January 15, 2019, 11:01:00 AM
It looks like a synced oscillator circuit. If I was feeling pedantic, I'd have to argue with the description of the circuit as a "filter", but luckily I'm not feeling pedantic so I can just let it go and sit over here and do some breathing exercises...breathe....breathe...breathe...;)

Sorry, but if I had called her Barbara it would be even more misleading ;)
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on January 15, 2019, 11:10:08 AM
Extremely cool design.  I was playing around EQ'ing the output and there's a lot of sounds in there.

Feel free to design an amazing EQ section for it. ;)

Where did you get the idea for diode and 4n7?   It's not a normal thing to do.

The idea for the diode and 4n7 (2n2 is even weirder) is just based on trial and error. I just like to play around and try different stuff. Most of them is textbook, but the other half is experimental just like that diode and cap.

I heard this track a few months back (Synthy bass comes in a 0:30).   I wonder if your circuit can help get that sound.
https://www.youtube.com/watch?v=boLGFfnCZDg

I will listen to it later and tell you.

Title: Re: I've designed a Filter Pedal for Bass
Post by: rankot on January 15, 2019, 12:41:16 PM
Does it have to be LM567, or I can use LMC567?
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on January 15, 2019, 02:15:33 PM
Suppose so. Ive used ka567 / ne567 and lm567 before. Please let me know if it works
Title: Re: I've designed a Filter Pedal for Bass
Post by: Marcos - Munky on January 15, 2019, 02:33:21 PM
Firstly I thought this was something similar to Hemmo's Noise 567:
(https://i.postimg.cc/r0KdKscs/Hemmo-s-Noise-567.gif) (https://postimg.cc/r0KdKscs)

But yours is different. For example, your frequency cap is between pins 2 and 3, while Hemmo's between pin 6 and ground. A suggestion to try from Hemmo's one is to get the output from pin 2 instead of pin 1.

Also, Tim Escobedo have a modified version of Hemmo's circuit called Thing Modulator, where he stated a LMC567 would reduce oscillation bleeds when the effect is bypassed. So an LMC567 probably will works great on this one.

Could you draw a schematic of yours? I know it's a simple design, but my mind can't understand vero layouts.
Title: Re: I've designed a Filter Pedal for Bass
Post by: rankot on January 15, 2019, 03:42:42 PM
Is this correct schematic?


(https://i.postimg.cc/bSk2M0Wx/567.jpg) (https://postimg.cc/bSk2M0Wx)
Title: Re: I've designed a Filter Pedal for Bass
Post by: Marcos - Munky on January 15, 2019, 03:51:35 PM
I compared the schematic to the layout and it seems correct. I'll draw a layout for a 1590A later.
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on January 16, 2019, 02:21:08 AM
Ive build the ring modulator years ago. Its very noise. This design is very quiet even with normal 567 ics like lm567 ne567 ka567. The sound is also nothing like the thing modulator.

Thanks for the schematic!!!
Title: Re: I've designed a Filter Pedal for Bass
Post by: Marcos - Munky on January 17, 2019, 03:03:30 PM
Well, didn't made a 1590A layout, but the guys at Efffects Layouts made one:
http://effectslayouts.blogspot.com/2019/01/bass-filter-pedal.html
It should be an easy fit in a 1590A.
Title: Re: I've designed a Filter Pedal for Bass
Post by: bluesdevil on January 18, 2019, 02:49:55 AM
Very cool and easy build! I have that chip stashed away somewhere and this will be a good excuse to dig it out.
Thanks for sharing.
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on January 18, 2019, 04:17:12 AM
Well, didn't made a 1590A layout, but the guys at Efffects Layouts made one:
http://effectslayouts.blogspot.com/2019/01/bass-filter-pedal.html
It should be an easy fit in a 1590A.

I see they've added a 100 uf cap in the power section. Has anyone, besides me, build this pedal?
Title: Re: I've designed a Filter Pedal for Bass
Post by: rankot on January 18, 2019, 04:34:20 AM
I see they've added a 100 uf cap in the power section. Has anyone, besides me, build this pedal?

No I didn't, but I will :)
Title: Re: I've designed a Filter Pedal for Bass
Post by: DDD on January 19, 2019, 05:28:47 AM
Surprisingly simple schematic based on the not so simple theory.
It's a real masterpiece!
Thanks for sharing!
*** By the by I'm sure that serial BLUE LED instead of the 7806 will do the same work perfectly, giving a bright indicator light as a bonus.
Title: Re: I've designed a Filter Pedal for Bass
Post by: rutabaga bob on January 21, 2019, 03:08:24 PM
Nice, simple, easy circuit - but mines not working.  Used an audio probe...there is no signal at either pin 2 or pin5.  Triple-checked against the schematic and all looks right.  Possible toasted chip?
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on January 22, 2019, 04:22:56 AM
I've build a few last week with ne567 and ka567. All from the layout above and they all work. Which 567 type did you use? Maybe yours is indeed broken. Let me know if theres something unclear and I will do my best to assist.
Title: Re: I've designed a Filter Pedal for Bass
Post by: rutabaga bob on January 22, 2019, 08:54:53 AM
Ive got LMC567CMs...which I think are CMOS.  Perhaps it got zapped.  Im preparing to order some plain 567s to try out.  Thanks!
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on March 26, 2019, 03:55:04 PM
I'm sure that serial BLUE LED instead of the 7806 will do the same work perfectly, giving a bright indicator light as a bonus.
How would you wire it, given that the led has 2 lugs, and the regulator 3 ?
Title: Re: I've designed a Filter Pedal for Bass
Post by: rankot on March 26, 2019, 05:27:22 PM
In series from V+ to Vcc pin of the IC. It must have 3.0V voltage drop to work that way.
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on March 26, 2019, 05:29:59 PM
Thank you, Rankot  ;)
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on March 30, 2019, 03:05:26 PM
Hello,
I've been suggested to put a booster in front of that effect (which I haven't built yet), so i made this little layout, trying to merge the original circuit with a JHS minibomb (http://tagboardeffects.blogspot.com/2013/04/escobedo-duende-jfet-jhs-minibomb.html).
The good thing is that now you can dial in both the right input & output levels.

I think the "merging" is quite ok, but i am unsure about the fact that now some component are not mandatory (since it is "two in one")...
Does anyone think the layout is ok ?

(https://i.imgur.com/rP8aO3e.png)
Title: Re: I've designed a Filter Pedal for Bass
Post by: duck_arse on March 31, 2019, 10:00:18 AM
most people here hate reading veroboard, so if you show your circuit for that board, it will help us all much to say correct or not.
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on March 31, 2019, 12:25:02 PM
most people here hate reading veroboard, so if you show your circuit for that board, it will help us all much to say correct or not.
Sorry, Im' not sure i understand what you mean (The original layout is also a veroboard, not a schematic) ?
I just took the original layout, and tried to merge it with a booster layout (http://tagboardeffects.blogspot.com/2013/04/escobedo-duende-jfet-jhs-minibomb.html), so i do not have a schematic.
Title: Re: I've designed a Filter Pedal for Bass
Post by: rankot on March 31, 2019, 01:11:37 PM
You don't need 1M or 100k resistor, they are just put in parallel.

This shall be the correct schematic (using blue LED instead of LM78L06):
(https://i.postimg.cc/CzS05ccp/567.jpg) (https://postimg.cc/CzS05ccp)
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on March 31, 2019, 03:00:40 PM
Thank you, Rankot.

So, if i read your schematic correctly, I should remove the 1M resistor, and keep the 100K ?
Also, I see only 4 caps on your schematic, while the "dual" layout (gathering a booster + the filter) should have 7 : 3x100nF, 1x4.7nF and 3 electro : 1F, 22F, 100F.
Should I then remove the 100nF cap (going to 567's pin#3), as well as the 22F and 100F electrolytics ?
Title: Re: I've designed a Filter Pedal for Bass
Post by: rankot on April 01, 2019, 03:10:42 AM
If I have read this vero correctly, 100uF and 22uF are in parallel and used for power filtering, so you don't need 22uF cause 100uF will do the job.

You also don't need two of 100n coupling caps, one is quite sufficient, so yes, you can remove 100n and 1M in top part of a vero and set the green line to connect points I2 and E4.
Title: Re: I've designed a Filter Pedal for Bass
Post by: duck_arse on April 01, 2019, 09:23:22 AM
most people here hate reading veroboard, so if you show your circuit for that board, it will help us all much to say correct or not.
Sorry, Im' not sure i understand what you mean (The original layout is also a veroboard, not a schematic) ?
I just took the original layout, and tried to merge it with a booster layout (http://tagboardeffects.blogspot.com/2013/04/escobedo-duende-jfet-jhs-minibomb.html), so i do not have a schematic.

what you showed is a veroboard layout. and you've added something to the original circuit, so what I wanted was a new circuit diagram, containing what you've added and what it's been added to. the fet gate was bothering me, is all. [I'd say you should take that now spare cap and put it in the hot/CW lug of the gain pot, with the now spare 1M as a pulldown.]
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 01, 2019, 03:06:24 PM
what I wanted was a new circuit diagram, containing what you've added and what it's been added to.
Ok. I took this (the original was a veroboard) :
(https://i.postimg.cc/4d9hshWR/filterrrr.jpg)
And this (left circuit) :
(http://1.bp.blogspot.com/-qJnkA79h5zc/UXzcfX_imCI/AAAAAAAACM4/CA-Coay0LqE/s1600/Escobedo-Duende-JFET-JHS-MiniBomb.png)

And tried to merge them.


the fet gate was bothering me, is all. [I'd say you should take that now spare cap and put it in the hot/CW lug of the gain pot, with the now spare 1M as a pulldown.]
Thank you for the tip.
Is this to avoid crackles when turning the gain knob ?

Quote
If I have read this vero correctly, 100uF and 22uF are in parallel and used for power filtering, so you don't need 22uF cause 100uF will do the job.
You also don't need two of 100n coupling caps, one is quite sufficient, so yes, you can remove 100n and 1M in top part of a vero and set the green line to connect points I2 and E4.
Thank you, Rankot. I updated my layout (i moved a couple parts, in order to make it more compact), i hope it is correct.


(https://i.postimg.cc/qNpphVgS/Bass-Filter-w-added-Booster-REDUX1-2.jpg) (https://postimg.cc/qNpphVgS)
Title: Re: I've designed a Filter Pedal for Bass
Post by: rankot on April 01, 2019, 03:59:00 PM
Yes, I guess it's fine. I will try to breadboard this tomorrow.
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 01, 2019, 04:03:53 PM
Thank you for your tips.
I will do, too, but i haven't received my 567 yet, so i won't be able to try it until a while.

By the way, i made an even more compact layout, with a 2PDT to switch between 3capacitor values for the filter (instead of 2 on the original design).
If you breadboard it, I would be curious to know your thoughts about different diodes and cap values...

(https://i.postimg.cc/CZwPq8BH/Bass-Filter-w-added-Booster-REDUX1-2-Compact-w-2-PDT.jpg) (https://postimg.cc/CZwPq8BH)
Title: Re: I've designed a Filter Pedal for Bass
Post by: rankot on April 02, 2019, 02:19:46 AM
I suggest you to switch places of diode and blue jumper, if you put diode like this, it will not be possible to mount trim pot.

Also, with this kind of DPDT and capacitor arangement, you will have two different capacitances: 1n1 and 1n5. Is that what you want?
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 02, 2019, 11:26:23 AM
Quote
Also, with this kind of DPDT and capacitor arangement, you will have two different capacitances: 1n1 and 1n5. Is that what you want?
Doh ! You're right : i wired them in series, just as if it was resistors  :icon_redface:
No, this is not what i want : i will come back to my initial setup (with a 1PDT, and without the 2.2nF cap).
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on April 02, 2019, 03:27:31 PM
you could also try a rotary switch if you want to experiment. one for the diodes and leds and one for the different caps.

https://www.musikding.de/Rotary-switch-1P12T-sealed

gives you 12 options.. could be pretty crazy
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 02, 2019, 03:34:24 PM
Hi, Fuzzzz.
I had thought about that (i have a couple rotatory switches like that). But i think i would rather experiment with various values on the veroboard, and keep the two i like the most :)
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 05, 2019, 06:56:55 PM
I will not have time this week-end for building it, but I should try next week.
@Rankot, did you manage to breadboard it ?
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 24, 2019, 03:10:48 PM
Hello.
I built it today (nearly twice) :
First, I followed the layout i made (adding a booster in front of the original circuit) : it didn't work :(
I checked two, three times, and spent a couple hours trying to debug, without luck...

Then, i wanted to try a more "barebones" version, to see if my layout or my build is buggy, so i built the original layout (just adding a 100F input capacitor, and omitting the output volume knob) : it works.
However, I only get a distorsion, without any filtering effect  :icon_confused:
I had socketed the 4.7K capacitor and the diode, so i wanted to try different sonic flavours : removing the cap didn't change the sound, swapping the 4.7K for a 2.2K or for a 6.8K didn't produce any change either...
The filter knob doesn't seem to affect the sound either.
Changing the diodes change the sound a little bit (with a Germanium, the sound is a bit softer, less harsh in the bass range. With a 5mm red led, you have to push the input level a lot to hear some changes).

I am using a "regular' lm567cn (not a LMC567CN : does it matter ?)

I like the "core" sound i am getting out of it, but i am wondering why the filter knob and the capacitor doesn't produce any change in sound ?
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 24, 2019, 03:55:40 PM
[edit]
- I changed the Germanium diode by the recommended 1N4148 : it helps taming the sound a lot.
- Also, I was using a 25K pot for the filter, and a 10K is really mandatory (maybe 5K is even better ?) : the "filter" knob acts more like a "fuzz amount" pot, and with 10K it comes from "no fuzz" to "a lot of fuzz" very quickly.
- But, I am still not getting the nice filtersweep effect i can hear in the demo, and changing capacitor values doesn't seem to affect the filter sound...
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on April 24, 2019, 04:23:00 PM
Hello.
I built it today (nearly twice) :
First, I followed the layout i made (adding a booster in front of the original circuit) : it didn't work :(
I checked two, three times, and spent a couple hours trying to debug, without luck...

Then, i wanted to try a more "barebones" version, to see if my layout or my build is buggy, so i built the original layout (just adding a 100F input capacitor, and omitting the output volume knob) : it works.
However, I only get a distorsion, without any filtering effect  :icon_confused:
I had socketed the 4.7K capacitor and the diode, so i wanted to try different sonic flavours : removing the cap didn't change the sound, swapping the 4.7K for a 2.2K or for a 6.8K didn't produce any change either...
The filter knob doesn't seem to affect the sound either.
Changing the diodes change the sound a little bit (with a Germanium, the sound is a bit softer, less harsh in the bass range. With a 5mm red led, you have to push the input level a lot to hear some changes).

I am using a "regular' lm567cn (not a LMC567CN : does it matter ?)

I like the "core" sound i am getting out of it, but i am wondering why the filter knob and the capacitor doesn't produce any change in sound ?

I hope you mean 4,7 nf instead of 4,7 k??

also, can you include a picture of your build. might be easier to check since its such a small print.
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 25, 2019, 03:10:49 AM
I hope you mean 4,7 nf instead of 4,7 k?
Yes, sorry for the typo  :icon_redface:

also, can you include a picture of your build. might be easier to check since its such a small print.
I will, later tonight (at the moment the light is pretty bad and the picture are not clear enough).
But the "barebones" build is very rough (with big green caps and sockets)...
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 25, 2019, 04:01:56 AM
Ok, I managed to get not-too-fuzzy, not-too-blurry, not-too-dark pictures of the "small" build (without booster, switch or output volume pot).
I hope that helps ?

With this build, i get distorsion, the filter pot action is rather audible, but i don't hear filtering effect, nor any filter sweep (filter env).

https://imgur.com/a/0Z9aaiz

Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 25, 2019, 04:05:32 AM
And an album with the "big" version (following the layout i posted above, including a booster).
I think something might be wrong with the layout (or I made mistakes in the build), as i don't get sound out of it.
I have set the trimmer so i get 4.5-4.8V for the transistor bias.


https://imgur.com/a/ZLiOxuG
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on April 25, 2019, 07:42:16 AM
I'm looking at the small 'bass filter only' version. It seems like your diode is upside down. Im checking as far as I can see. Make sure all the cuts are really cut. Maybe by using a Multimeter to check continuity.
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on April 25, 2019, 07:48:04 AM
what type of 567 chip are you using?
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 25, 2019, 07:52:59 AM
Thank you, Fuzzzz  :)
Quote
It seems like your diode is upside down.
Yes indeed : i tried with the diode in both ways, and i think i took the picture with the diode upside down.
But i have tried with the diode in the right orientation, of course :)

Quote
Make sure all the cuts are really cut. Maybe by using a Multimeter to check continuity.
I checked (on the "small" version, not on the bigger version).
I will check continuity again.

Quote
what type of 567 chip are you using?
I am using a "regular' lm567cn (not a LMC567CN).
I also tried with 2 different 567 chips (to rule out a bad one, as i have a bundle of 10 chips).
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on April 25, 2019, 07:59:45 AM
After checking continuity, could you also check for solder bridges between paths. Also, if you would like to check that the ground wire (middle lug of the voltage regulator) is connected tot pin 7 of the 567 chip?
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on April 25, 2019, 08:00:29 AM
are you using a bassguitar for testing? if so, a passive one?
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 25, 2019, 08:06:00 AM
Quote
are you using a bassguitar for testing? if so, a passive one?
I am using it with a synthesizer (i am not guitarist or bassist).

Quote
After checking continuity, could you also check for solder bridges between paths.
I will.
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on April 25, 2019, 08:43:11 AM
i dont know if its going to sound great with a synth signal, yet. i will have to try this myself. I designed this for bass guitar. when using with bass the filter pot doesnt need to be bigger then 10k.
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 25, 2019, 09:30:33 AM
i dont know if its going to sound great with a synth signal, yet. i will have to try this myself. I designed this for bass guitar. when using with bass the filter pot doesnt need to be bigger then 10k.
Do you mean because of possible impedance issue, or about frequency content (if the latter, i was making the test with a monophonic bassline. In fact, a sound and a phrase very close to the one you play in your video).
Title: Re: I've designed a Filter Pedal for Bass
Post by: duck_arse on April 25, 2019, 11:09:37 AM
from "LMC567 Low-Power Tone Decoder" datasheet by TI:

Code: [Select]
The LMC567 can be directly substituted in most LM567 applications with the following provisions:
1. Oscillator timing capacitor Ct must be halved to double the oscillator frequency relative to the input frequency
(see Oscillator).
2. Filter capacitors C1 and C2 must be reduced by a factor of 8 to maintain the same filter time constants.
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on April 25, 2019, 11:42:30 AM
i dont know if its going to sound great with a synth signal, yet. i will have to try this myself. I designed this for bass guitar. when using with bass the filter pot doesnt need to be bigger then 10k.
Do you mean because of possible impedance issue, or about frequency content (if the latter, i was making the test with a monophonic bassline. In fact, a sound and a phrase very close to the one you play in your video).

yes.. thats what I meant. But, to be honest I havent tried it yet. Will try some drummachines as well. and maybe some other noise makers. Did you find anything out of the ordinary yet?
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 25, 2019, 02:29:24 PM
from "LMC567 Low-Power Tone Decoder" datasheet by TI:

Code: [Select]
The LMC567 can be directly substituted in most LM567 applications with the following provisions:
1. Oscillator timing capacitor Ct must be halved to double the oscillator frequency relative to the input frequency
(see Oscillator).
2. Filter capacitors C1 and C2 must be reduced by a factor of 8 to maintain the same filter time constants.
Thank you, Duck Arse, this might be very good to know  :icon_cool:
I will adjust the values accordingly.
If i understand correctly, i should try to swap the 4.7nF cap by a 560pF, and leave the rest untouched ?

@FUzzzzz, did you use LMC567CN in your builds, or "regular" LM567 ?

Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 25, 2019, 05:48:11 PM
Little update :
I didn't yet made a continuity test, but i swapped the 4.7nF cap with a 560pF : the sound is the same. Whatever cap value i throw in, the sound doesn't change (even without any cap, it's the same).

Also, I noticed that with the negative side of the diode towards the bottom (as indicated in the schematic), the sound stays the same. If i put the diode (1N4148) with the cathode up, the "filter" knob acts somewhat as a lowpass filter, but without any frequency sweeping (or a fuzz dry/wet mix, ruling out the fuzz's high harmonics).

I still don't hear any filter sweep effect, and the sound reminds me a distorsion effect, without any obvious filtering.

What puzzles me is that the circuit is such an easy build with low part counts, I really can't see what i have done wrong  (both times -with or without booster- it didn't work as expected) :icon_question:
Title: Re: I've designed a Filter Pedal for Bass
Post by: FUZZZZzzzz on April 26, 2019, 03:28:12 AM
this design has been succesfully build by at least a couple of people, so it should work according to the layout.

I've used the 'normal' 567 (KA567) for this build. i hope the answer is in the continuity test. can you unsolder the 100 uF cap. Thats the only thing different from my original design.
Title: Re: I've designed a Filter Pedal for Bass
Post by: duck_arse on April 26, 2019, 10:45:25 AM
arum-ah, sorry for confusing anyone with my confusion. I seem to be thinking of a something else, that actually specs an LMC ...... sorry about that, chief!
Title: Re: I've designed a Filter Pedal for Bass
Post by: snk on April 27, 2019, 05:15:16 AM
Hello,
First report :
Also, if you would like to check that the ground wire (middle lug of the voltage regulator) is connected to pin 7 of the 567 chip?
Yes, it is.
I tested with my DMM (middle lug of the voltage regulator to pin 7 of the 567 chip), and it beeps as expected.

After checking continuity,
ROW A : no beep produced by the DMM, as expected => GOOD.
ROW B : It beeps, as expected => GOOD
ROW C : no beep, as expected => GOOD
* ROW D : my DMM screen displays a value around 1030, but it doesn't beep => strange *
ROW E : no beep, as expected => GOOD
ROW F : no beep, as expected => GOOD
ROW G : It beeps, as expected => GOOD
ROW H : It beeps, as expected => GOOD

could you also check for solder bridges between paths.
I didn't noticed anything suspect.