I finally got the chance to make a real looking pedal and as professional as possible.
It looks amazing, sounds amazing.
But there is a couple of noise problems.
First, when the pedal is bypassed there is a high noise floor (more noise than if i removed the pedal from the chain completely) and when the pedal is turned on, the noise ofc gets higher because it's a gain pedal.
I used a plastic box as i couldn't find a metal box where i live. I tried to shield the enclosure with aluminum foil and connect a wire from circuit ground to the back of one of the pots so the enclosure can be grounded but that was hopeless.
I was wondering what could the noise issues come from and how could i figure out where it's coming from?
Could it be a ground loop? Could it be that the power cables are close to signal cables? Could it be something wrong with the DPDT bypass switches?
Could it be something wrong with the board itself? So many possible causes!
Here are a couple images of the board before i boxed it, after i boxed it and the box itself.
(https://i.postimg.cc/vcKRXKxj/Messenger-creation-90-A17411-4-BE7-4-DE3-8-E83-E21538-D0-C4-FC.jpg) (https://postimg.cc/vcKRXKxj)
(https://i.postimg.cc/d7MbcTBj/IMG20250220190145.jpg) (https://postimg.cc/d7MbcTBj)
(https://i.postimg.cc/v4nKhZsg/IMG-20241123-025037.jpg) (https://postimg.cc/v4nKhZsg)
(https://i.postimg.cc/gLrSZYs0/IMG-20241123-025026.jpg) (https://postimg.cc/gLrSZYs0)
Unfortunatley i didn't take pictures of the solder side before boxing.
I could record some sound examples for the noise and i think i would definitely need to take it apart to see the issue so i could take pictures of the solder side then.
I am just sad that after all this work, it has issues.
Lead dress + plastic enclosure is 100% your problem
Quote from: drdn0 on February 20, 2025, 04:11:35 PMLead dress + plastic enclosure is 100% your problem
What is lead dress?
Also if that's the case, why is it making noise even on bypass?
(https://i.postimg.cc/8jN34SCt/TB-basic.jpg) (https://postimg.cc/8jN34SCt)
I used this wiring diagram for true bypass, and since there is 2 true bypass switches, i connected the jack out of the first one to the jack in of the second one and then continued the rest as the diagram.
1) Congratulations on attempting and succeeding (apart from the noise) with a perf project as complex as this.
2) There is waaaayyyyy too much wire in there, even if it was mounted in a cast aluminum enclosure. Figure out how to trim the length back on some of those leads, so that the slack is not near anything sensitive. Remember that noise doesn't come JUST from the circuit, but also from wires between the in/out jacks and bypass switch that might be too close to something they should not be. Actually, where IS your bypass switch?
3) 1% low-noise metal-film resistors are so inexpensive these days. If you can, consider replacing the resistors on the first op-amp stage with 1% units.
4) The 4558 is a decent op-amp for many many purposes, but is not the lowest-noise unit out there. The stock KoT uses the 4580 dual op-amp, which has noise specs about 4x better than a 4558.
+1 to what said above.. :icon_wink:
@my dear Doctor: Would you ever suture an epidermal tear is such a way..?? :icon_lol:
Quote from: Mark Hammer on February 20, 2025, 08:08:06 PM2) There is waaaayyyyy too much wire in there, even if it was mounted in a cast aluminum enclosure. Figure out how to trim the length back on some of those leads, so that the slack is not near anything sensitive. Remember that noise doesn't come JUST from the circuit, but also from wires between the in/out jacks and bypass switch that might be too close to something they should not be. Actually, where IS your bypass switch?
3) 1% low-noise metal-film resistors are so inexpensive these days. If you can, consider replacing the resistors on the first op-amp stage with 1% units.
Thank you mark for explaining what's happening.
First thing is, unfortunatley i don't have metal film resistors where i live.
Regarding the op-amp, i replaced the 4558 with a TL072 and the noise is somewhat better.
I also wrapped the input and output wires with aluminum tape and that helped a little too.
Regarding the wires, i know i messed that up as i didn't have the box when i was soldering everything and i kinda didn't know about lead dressing. I will try to cut some a little (that's gonna be a lot of desoldering and soldering :icon_sad: )
My bypass switches are the ones at the very end, the far end right one and far end left one.
I don't have a problem with noise when engaging the pedal, but what bothers me most is the noise when bypassed!
Here is a better resolution picture for the whole thing.
(https://i.postimg.cc/fSfgSSk6/IMG-20250221-151009.jpg) (https://postimg.cc/fSfgSSk6)
Btw the diodes on the switches are not touching however they may look like it in the picture.
Don't think of the extra wire as "messing up". I had to shorten wires last night, myself, on something I kluged onto a little perfboard, in order to fit it inside an enclosure. It happens. We don't always know in advance how much wire we will need to go from this thing to that one, so it is a completely forgiveable "sin". But once we have the circuit/device working properly, it's a good idea to trim excessive wire, while maintaining enough slack to be able to move, inspect, or rotate things without fracturing wire.
I'm pleased that you were able to reduce the noise, even just a bit, if not completely. There is nothing really "wrong" about plastic enclosures. I have many pedals in plastic enclosures - some homemade and some commercial - with negligible noise. A shielded cable from the input jack to the circuit input can be very helpful; especially since the circuit applies a lot of gain. You don't want any noise coming to the input to be amplified more! :icon_eek:
On many of my homemade pedals in plastic enclosures I cut out a piece of (automotive) copper shim material to sit on the underside of the top of the enclosure (the "roof"). I punch holes in it using one of those little handheld punches normally used to put holes in paper documents you want to fit in a binder. The shim often needs to be buffed a bit with steel wool to remove tarnish. But once clean, it offers a nice ground plane to solder wires to. It is held in place by the pots poking through the holes, and attached to the enclosure. Now, none of this necessarily removes hiss generated internally, but much of the hum a circuit might pick up comes from sources above a pedal on the floor, and the copper sheet does a reasonable job protecting against that.
Quote from: Mark Hammer on February 21, 2025, 09:18:30 AMDon't think of the extra wire as "messing up".
You are right, it's just gonna be a lot of work and with those pcb mount pots pins ;D
The noise wasn't reduced much, maybe 5% or so but it's still plenty. And i noticed that the noise isn't static but has some weird sounds like electrical zaps sometimes.
Here is a sound clip (https://drive.google.com/file/d/1hJcWu4LW-fP2l_ymf_2r7wslvAFXeH6J/view?usp=drivesdk) of what's happening. At the beginning of the clip the pedal is bypassed then you hear a couple pops that are from me turning on and off the switches for each side.
Then at the 40 second mark you hear 2 loud pops and those are from my pickup selector switching to the HB bridge pickup which is much more noisy than the neck pickup (maybe there is something wrong with it? Idk)
Btw i had the amp volume pretty high thought until before i started playing i lowered it.
Thanks. That soundclip is very helpful. Maybe there is some hiss in there, but 95% of what we are hearing is EMI/hum.
Try powering up the circuit somewhere that does not place you so close to transformers, or motors, or anything else that uses AC. How close to your computer were you when you recorded that?
I don't say any of this to blame you. Rather, those sources of noise (and there are many kinds) can be something that varies, simply depending on where you are. Important to be able to rule those out, before coming to any conclusions about what "the problem" might be.
Rule #1 about troubleshooting: always start by checking the obvious, before investing time in the exotic. The worst that can happen is that you can comfortably say "Well I know it's not THAT".
Quote from: Mark Hammer on February 21, 2025, 01:05:36 PMsomewhere that does not place you so close to transformers, or motors, or
+1. Just move it, turn it. Internal crap won't change much. External crap can change a lot in a few inches (unless it is a megawatt power facility next door, or the guy by an electric train line).
And if Mark is hearing "PC", he's likely right. Only these days "PC" is everywhere, from a multimeter to a cellphone or AskDora home control system.
Plastic cases for LOW-level guitar are a lot of trouble unless you have industrial metallizing systems. There are fewer metal boxes around, but they can be found. House electrical wiring. Pots and pans. My latest 'find' is dog tick&flea collar tins (but contaminated with strong insecticide). Used to be candy, Bandaid, and tobacco tins, but they have vanished?
Depending on local building custom, you may find thin Copper as roof flashing. You want to find a roofer and buy scraps, the good stuff sells in $100 lots. Thinner stuff for stain-glass work and (!!) shielding inside guitars costs less.
Warm air ducts are sealed with Aluminum (not cloth!) "Duct tape". A small roll is $7 here, might do several guitars and all the FX boxes they need. Can't solder, use tooth-washers (such as around jacks).
I wasn't near any computer or anything that uses AC. I recorded with my phone and placed it away on the carpet.
I think there might be something wrong in the board itself idk but the level of noise when i turn the drive around 3 o'clock is unbearable. And when i roll my guitar volume down it produces a strange noise, like the noise you get when you touch the input wire with your finger. And also when guitar volume pot at zero, there is still noise! Hahaha
And if i pick the enclosure up from the ground, noise decreases. Such a wicked thing that is.
I think i need to take the board out and see if i messed something up.
I know you are not blaming me man, what's for to blame. We are just helping each other out in our hobby :icon_wink:
"slug tape", in the garden section of your megastore hardware, is thin adhesive-backed copper tape, for putting around the pot-plants you want to protect from slugs and snails.
it is good for sheilding wooden enclosures, would also be good for plastic.
ok, so i built another whole board with shorter wires and i insulated the whole box with aluminum tape and made sure that they connect to each other and the noise went away comletley. but there is one thing that is not very good. there is noise but when i touch the strings or any metal on the pedal the noise goes away. could this be a ground loop? as i didn't use the star ground thing.
i tested it with only the guitar and amplifier with no pedals at all and it does the same thing however the level of noise is lower.
could this be a problem with the guitar itself? idk
i read somewhere that this is normal and has something to do with our bodies.
i made sure that everything that needs to be grounded in the pedal has continuity.
Quote from: Lost_soul on March 14, 2025, 05:21:31 PMwhen i touch the strings or any metal on the pedal the noise goes away.
There's always buzz on your body (if you are anywhere with electricity).
Everybody should have clip leads.
-(https://i.postimg.cc/34gG9kmM/clip-leads.jpg) (https://postimg.cc/34gG9kmM)-
Run from a string-end to the guitar's jack-- in fact just tap it to hear a difference.
If that helps, do it right. Usually internal ground wire. May as well line the pot-cavity with metal foil also.