BOTH of my Thermionic Deluxe have the same ground issue HELP

[Andrion]

I built two Thermionic Deluxe:

- the first one was from this post, and god, you guys have no ideia how much I struggled to find the problem, but still no success

- since my friend paid the material so I could built a Thermionic Deluxe for him and the first one didn't worked, I bought new PCB + parts (re-using just the same enclosure and knobs than the previous) with my own money to build a new one and end this problem;

- I built the second one perfectly and carefully; tested with it above my amp and everything went perfectly; and at the second I put it on the ground the problem showed again; a loud hum even when the pedal is bypassed, but when the pedal is turned on, it turns apocalyptic; I tried put it over a towel or on the pedalboard to see if the hum persists, but it only stops when the pedal is about 1meter above the floor;

some considerations:

- I even tested connecting the in and out jacks directly instead of passing through the 3pdt's pcb on the first pedal and the problem persists.

- I tested it with different guitars, cables, power supply, amps and everything two times in 3 different places: my house, my friend's house and my friend's studio (so the problem is not with my house's electrical system)

- I already made a Dirty Sanchez that went perfectly and don't have this problem; I'm considering building two of them in one enclosure, but damn...

the following paragraph is not about the problem itself, but just about frustration:
I guess you guys from USA or Europe have no ideia of how expensive is to import one these PCB + components + shipping to Brazil; it's literally a 1/4 of the minimum wage (and as a muay thai trainer, I make even less than the minimum wage) because of the shitty abusive taxes, shitty money that worth nothing and shitty corrupt government of this shitty country;
and I can't say that spending 2 times this amount for nothing is the best feeling in the world; I really don't want the make it for the 3rd time, specially because on the second one I couldn't really pay for it and just threw in my credit card PLEASE help me

 

[owlexifry]

what are you powering your builds with?
have you tried using a battery to eliminate power supply issues? (also can eliminate ground loop issues)

 

[Andrion]

what are you powering your builds with?
have you tried using a battery to eliminate power supply issues? (also can eliminate ground loop issues)

I'm using some different power supplies:

- the main one I use to test my pedals is a single pedal Strymon power supply that came with my Strymon Timeline (great quality), it works great with every other pedal;
- I used 3 different others that I just know that work well, including the main one in my pedalboard, which is a made in Brazil isolated one similar to Voodoo labs;

I haven't tried it with batteries because I don't have the adapter, but I don't think that is the problem since every other pedal (from pedalPCB or not) besides the Thermionic Deluxe model works fine with those power supplies

 

[owlexifry]

I'm using some different power supplies:

- the main one I use to test my pedals is a single pedal Strymon power supply that came with my Strymon Timeline (great quality), it works great with every other pedal;
- I used 3 different others that I just know that work well, including the main one in my pedalboard, which is a made in Brazil isolated one similar to Voodoo labs;

I haven't tried it with batteries because I don't have the adapter, but I don't think that is the problem since every other pedal (from pedalPCB or not) besides the Thermionic Deluxe model works fine with those power supplies

alright, show us some well-focused shots of the build.

let's see if we can find something...

 

[Andrion]

@owlexifry
This is the second/current build, that I built with all the careful in the world, so no cold solders, no connections/solders (that shouldn't touch) touching, no fried components, etc

 

[owlexifry]

@owlexifry
This is the second/current build, that I built with all the careful in the world, so no cold solders, no connections/solders (that shouldn't touch) touching, no fried components, etc

View attachment 80794

if you are having issues with the effect in bypass - then it has to be an offboard wiring issue.
(Q: how much heat has the switch been exposed to? these are the weakest point as far as offboard wiring goes).

1st observation:
as was mentioned in your other thread - you want to ensure the jacks (sleeves) have continuity to the enclosure - i'm seeing a lot of paint on the inside.
loosen the jacks and sand/file the jack hole area so that there is metal on metal contact between the jack and the enclosure.

 

[Andrion]

if you are having issues with the effect in bypass - then it has to be an offboard wiring issue.
(Q: how much heat has the switch been exposed to? these are the weakest point as far as offboard wiring goes).

1st observation:
as was mentioned in your other thread - you want to ensure the jacks (sleeves) have continuity to the enclosure - i'm seeing a lot of paint on the inside.
loosen the jacks and sand/file the jack hole area so that there is metal on metal contact between the jack and the enclosure.

A: My soldering iron is a cheap 30w without temperature display and I tried to make the soldering just long enough for it to work, afraid of frying anything;

I'll try sanding it;
just the in/out jacks or the power one too?

 

[owlexifry]

A: My soldering iron is a cheap 30w without temperature display and I tried to make the soldering just long enough for it to work, afraid of frying anything;

okie dokie.
(i use a cheapy 40W with no temp display too)

I'll try sanding it;
just the in/out jacks or the power one too?

input and output jack. (at least one of them)

power/DC jack is irrelevant (isolated / made of plastic)

 

[Andrion]

okie dokie.
(i use a cheapy 40W with no temp display too)


input and output jack. (at least one of them)

power/DC jack is irrelevant (isolated / made of plastic)

I did it on both in and out jacks with a nail sanding thing;
I really had hope in this, since the enclosure, knobs and circuit design are the only 3 things in common between both builds, but nothing changed; the noise still remains

 

[owlexifry]

audio probe time.

here's my copy+paste guide about audio probes:

IME, more often than not, pedal issues are usually overlooked build error(s).
the killer with pedals is, some errors can be very difficult to locate / identify.
this is where audio probes save the day.
you can look at a wiring/build layout for days and still not see the key point that's been missed / misplaced.
an audio probe will at least give you a reasonably pinpointed clue about where you've messed up on the circuit.

if there is any advice i can give, go and make yourself an audio probe setup:

all you need is:
- mono jack (send to an amp / stereo)
- insulated wire+alligator clip (to clip to ground)
- 100nF cap (voltage rating to your application, i used 630V cos the leads are robust and can use on amps)
- audio source to feed the pedal circuit input (guitar, music player, iphone )

what to do:
- feed some constant audio into the input of the pedal circuit being tested (iphone, mp3 player, whatever, use an adaptor etc.)
- with the tip of the probe (capacitor lead), you trace the signal from input jack, to switch, etc. along the circuit (schematic will help here), until you find where the signal is being lost/muted/weird/

 

[Andrion]

somehow it's worse;
now it's making the loud hum on bypass even if the pedal is lifted same thing as the previous build, after a couple days it stops working properly

 

[BuddytheReow]

It may be worth your while to swap the in/out wires for shielded wires. Make sure to ground both ends.

 

[Andrion]

It may be worth your while to swap the in/out wires for shielded wires. Make sure to ground both ends.

I know nothing about shielded wires, which one would you recommend me? anyways I'll have to import it, it will took a couple of weeks since I can test it; until that I question myself: if the problem is the wire, why every other pedalpcb I built worked properly and coincidentally the 2 Thermionic Deluxes had the exact same flaw after a couple of days?

 

[jwin615]

Sanity check. Did you try different cables?
Sitting it on the floor would change the cable angle, possibly highlighting a short that wasn't there before.

 

[Andrion]

Sanity check. Did you try different cables?
Sitting it on the floor would change the cable angle, possibly highlighting a short that wasn't there before.

yes, I tried different cables; my mogami 2524 with switchcraft connectors and my friend's A setup in his studio and his B setup in his house;
the hum immediately stops when we plug any other pedals (pedalpcb or not) in the place of the Thermionic Deluxe;

now the hum is constant, not only when the pedal is on the floor;
I thought it might be the paint/metal powder from when I sanded the in/out holes making some contact, but I remember that the first build also didn't had this hum at the first couple days; it's happening the exact same thing again

 

[Robert]

Does it hum in bypass if you unplug the power cable from the pedal?

 

[Andrion]

Does it hum in bypass if you unplug the power cable from the pedal?

it still exists, but gets more intense and change frequency with the power cable pluged

 

[Andrion]

also, the hum interacts with the circuit
it's passing through the distortion (when engaged) and change according to the turn of the knobs

the problem might be at the input or power