I've designed a Filter Pedal for Bass

[snk]

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.

[rankot]

I've built this at last! Works, but not as intended - Filter pot doesn't change the sound. Or exactly, it does change it when I put sine wave input into pedal and look output at the oscilloscope, but when I play through it, the change is inaudible. I tried with different diodes and capacitor values, but Filter pot behave the same.

[rankot]

Hm, I think I found what's the problem - it seems that capacitor across pins 2 and 3 needs to be bigger. I tried with an on-off-on switch with three different values: 1n2, 1n2+1n2 (2n4) and 1n2+3n3 (4n5), but all of them sounded almost the same with my bass, so I tried 1n2+10n and it suddenly started to works as I expected. I will leave this switch so I can test this with a guitar, maybe it will sound good with lower capacitances; if not, I will remove it and leave 10n only. I will certainly report my findings here.

[FUZZZZzzzz]

cool! glad you got it working. just build one for a touring friend with 2n2 and 4n7 options. and also between 1n4148 and some germanium on a switch. he likes it a lot on his bass. i dont like it that much on guitar though.

[rankot]

I also have a switch for diode type: LED/1N4148/BAT43, but to me it seems that it affects only the volume a little?

[FUZZZZzzzz]

i found that 1n4148 is the most stable sound for funky stuff, but germanium diodes can be quite crazy. leds didnt do much for me.

[rankot]

Interesting. I didn't try with Ge diode, but orange LED is the loudest of all three I tried.

[Rob Strand]

I've been meaning to try to understand that circuit for a while.    The way the IC is connected-up is very funky.

[rankot]

I've been meaning to try to understand that circuit for a while.    The way the IC is connected-up is very funky.

That's far above my level, so I don't try

But it seems to be working.

[Rob Strand]

That's far above my level, so I don't try

But it seems to be working.

I don't understand it either.   Yes, it clearly works