I would like to ask you about the origin of the static crackle and pops i can hear in the signal.

I can hear it when
- i plug my guitar cable in my VOX AC 15 (gain and volume up) and let it hang open ended (plus a lot of humm as it is not grounded)
- i can hear it when i have my Les Paul plugged to that cable, just less loud
- i can hear it when i add a battery fed pedal (Fuzz Face, Rangemaster, T-Rex Fuzz, ..) between my guitar nad amp
- i can hear it very loud when i plug a Colorsound Overdriver between my guitar and amp.

It sounds like pops and cracks, not periodical, more like random stuff.
Where does it come from? It is amplified by pedals, so it has to be induced before them ...

There are lots of sources of noise like that, Lino, and the study of this is quite involved.  I stick to the layman's view:  RF interference in the atmosphere (radio frequency crap from...radio stations, natural phenomena like solar activity and so on).   

Items in the vicinity like transformers, switching power supplies, microwaves and what have you can put out noise that we pick up.

'Shot noise' inside active devices like transistors and opamps is a thing...they make noise signals as they work which can be amplified and heard at the output. Things heating up can give off thermal noise just 'cuz'...it's physics. Tubes do this a lot due to the heater, but anything can.
 
Something off in the wiring can create noises, from a pickup or cable or whatever. Loose connections, frayed wiring...
 
Anything that has a current flowing through it can induce noise into a nearby component or conductor, including ground wires.   It's part of our life; embrace it!   

if i get it correctly, the amp itself crakles and pops.
i would try and (carefully!) make the tubes wiggle a bit in their sockets, in order to mechanically clean the tube-pins and sockets from oxidation.
 

There's a thread on Gearspace we're a guy had lots of odd noise in his studio space and sourced it to some unique electrical interference from a popcorn machine in the bar he lived above.

I know that's not helpful but it's funny.

Quote from: intripped on September 22, 2024, 08:45:43 AMif i get it correctly, the amp itself crakles and pops.
i would try and (carefully!) make the tubes wiggle a bit in their sockets, in order to mechanically clean the tube-pins and sockets from oxidation.
 

If the noise was sourced in the amp, the pedal would not amplify it. I will record it.

Quote from: GibsonGM on September 22, 2024, 07:18:08 AMThere are lots of sources of noise like that, Lino, and the study of this is quite involved.  I stick to the layman's view:  RF interference in the atmosphere (radio frequency crap from...radio stations, natural phenomena like solar activity and so on).

You are right Mike. This is a distinctive 'shooting' / popping, i thought this may be somehow recognized noise type. It definitely comes from the air and gets induced to the cable and amplified in the pedal / amp. The same sound is heard abroad - a fellow send me a pedal for repair with video where the sound is very audible and annoying when he puts a power boost clone between the amp and guitar. I can hear it too, but fairly quietly. It is not produced by the pedal as i stated before, it is merely amplified by the pedal.

It can be extremely hard to figure out where those things come from. Radar?  Cell phone towers?  I gave up long ago, and I just try to shield what I build the best I can.  I accept the noises as part of the analog world.   

Quote from: GibsonGM on September 22, 2024, 01:08:30 PMIt can be extremely hard to figure out where those things come from. Radar?  Cell phone towers?  I gave up long ago, and I just try to shield what I build the best I can.  I accept the noises as part of the analog world.   

They are all things out of your control but annoying just the same.

Welding equipment can be produce what seems like random crackling/arcing noise.

There was a long period where I had random "arcing" sounds coming through the audio.    I tried all sorts of things like turning off power circuits inside the house and at main board.   I even walked around the area with a small amplifier picking up stray noise on the input.    My PC speakers were quite susceptible to it.  I was convinced it was not from inside the house but I couldn't pin down what was causing it.

After many *years*, one day the noise was going nuts in my PC speakers compared to the normal occurrences.   Then IIRC within about 3 hrs we had a power outage.   It was like something faulty finally failed.  When the power system was restored the noise was gone.  More the point, I have not heard that "arcing" since.

I took to pedal to our rehearsal room, and it was completely quiet. So yep, something produces those spikes at around my household, and they induce on the cable/guitar. Rob, it is a good starting point to turn off my fusses, and i will do that. I have a battery operated amp so i can test it like that. But i live in an old commie block of flats and people around me drill, wash and so all the time.

I've heard the old commie housing is rife with noise sources.   

There are hobbyists who attach a loop antenna from an old AM radio to an amplifier to listen to the ambient sounds in the atmosphere.  They report some phenomena that you would expect like lightning activity but there are other phenomena as well.  One is the "dawn chorus" of signals from when the ionosphere layers dissipate and in some conditions, a howl from waves bouncing back and forth from the arctic to Antarctica.

If you are running into conditions where external noise interferes with the signal in your system, get the impedance down by using a buffer so capacitive coupling is weaker through the audio band.

That sounds like a healthy hobby. I will try it.

Quote from: Focalized on September 22, 2024, 11:39:31 AMunique electrical interference from a popcorn machine

I know I saw something about random generators but can't remember when or where. But maybe this will come up on some future search. 

True Random Number Generation IC RPG100 / RPG100F  web: http://www.fdk.co.jp
Natural phenomenon in CMOS is used to generate true random numbers.
 The circuit is composed of only CMOS and no external components are needed.
 Two independent white noise sources are used as the sources of randomness to eliminate external noise interferences.
 The quality of the true random numbers (correspond to FIPS140-2 Change Notice 1 standard).
 A randomness statistical test circuit is equipped (conform to FIPS 140-2 Change Notice 1 standard).
 The random numbers are generated at a High speed (up to 32 x 16bits random numbers are stored internally; and they can also be read at a high-speed).
 Lower power than your popcorn machine.
https://www.fdk.com/whatsnew-e/rpg100-e.html
https://www.fdk.com/whatsnew-e/release050930-e.html
FWIW: it is over 20 years old.