Lead Solder Buzz
- Thread starter jimilee
- Start date
comradehoser
Well-known member
Oh yeah, that's much different than the unboxed oscillation I have with the circuit. Sounds like grounding hum to me
jimilee
Well-known member
Me too, but I have audio in addition to this wonderful buzz. I’ve been away from it. I’m gonna wait a couple of days and go back to it. Do you happen to have IC voltages by chance?
comradehoser
Well-known member
Can obtain for you this evening, for sure.
My guess would be a solder bridge or poor grounding connection somewhere. Maybe a bridge somewhere devious, like under the ICs from a ground leg? Just a stab in the dark, but maybe you could do a continuity check with ground in the audio path?
My guess would be a solder bridge or poor grounding connection somewhere. Maybe a bridge somewhere devious, like under the ICs from a ground leg? Just a stab in the dark, but maybe you could do a continuity check with ground in the audio path?
comradehoser
Well-known member
Here you go, bud (IC # according to ppcb layout), 9v-in reading at 9.37v at jack and all knobs at noon. Same readings with footswitch in either position.
IC 1 (bottom center)
1: 0.988
2: 0.988
3: 0.922
4:-8.67
5: 0
6: -0.01
7: -0.001
8: 9.12
IC2 (top left)
1: -0.2
2: 0.001
3: 0
4: -8.68
5: 0
6: -0.002
7: -0.002
8: 9.12
IC3 (middle center)
1: 0.215
2: 0.121
3: 0
4: -8.68
5: 0
6: -0.02
7: -0.028
8: 9.12
IC100 (top right)
1: 9.12
2: 5.336
3: 0
4: -3.572
5: -8.60
6: 4.318
7: 5.732
8: 9.12
IC 1 (bottom center)
1: 0.988
2: 0.988
3: 0.922
4:-8.67
5: 0
6: -0.01
7: -0.001
8: 9.12
IC2 (top left)
1: -0.2
2: 0.001
3: 0
4: -8.68
5: 0
6: -0.002
7: -0.002
8: 9.12
IC3 (middle center)
1: 0.215
2: 0.121
3: 0
4: -8.68
5: 0
6: -0.02
7: -0.028
8: 9.12
IC100 (top right)
1: 9.12
2: 5.336
3: 0
4: -3.572
5: -8.60
6: 4.318
7: 5.732
8: 9.12
@jimilee what do you mean 7 o'clock? 7/10 on the gain pot? Or just barely up?
Sorry, 7:00 equates to SSW, pot in off position for me.
Same sound with nothing plugged in?
Edit. Is the growth of the noise from turning a pot or is it a building oscilation?
May try swapping IC3 as it's the only one that's utilizing both side of the 072. Maybe there's some crosstalk internally?
Sorry, 7:00 equates to SSW, pot in off position for me.
Same sound with nothing plugged in?
Edit. Is the growth of the noise from turning a pot or is it a building oscilation?
May try swapping IC3 as it's the only one that's utilizing both side of the 072. Maybe there's some crosstalk internally?
Last edited:
jimilee
Well-known member
Sorry, yes, just barely up. Same sound with nothing plugged in. All the grounds connect where they’re supposed to. I got the voltages from @Giorfida, those all look good. Solder has been reflowed for a third time. Ran a lead between all the components on the solder side to make sure there weren’t any invisible bridges. Real head scratcher.
comradehoser
Well-known member
Actually, my idea wasn't to check for ground where there should be ground, it was to check for ground continuity where there shouldn't be ground, like the side of components facing the audio path or in it directly.
Is that electronically feasible? I think so ...
If your solder side is clean, maybe look at the solder points between the belly of the ic and the board (or the sockets and the board). It's possible a bridge could exist there between the pins on the top side, maybe, if the solder bubbled out.
Maybe a bad IC or poorly seated leg? Can't remember if you socketed them.
Is that electronically feasible? I think so ...
If your solder side is clean, maybe look at the solder points between the belly of the ic and the board (or the sockets and the board). It's possible a bridge could exist there between the pins on the top side, maybe, if the solder bubbled out.
Maybe a bad IC or poorly seated leg? Can't remember if you socketed them.
jimilee
Well-known member
Ah, ok, I see what you’re saying. I can do that. The IC is socketed, I have tried several different ones including the 1044. I’ll check the socket legs to see if there are any bridges.
If there is overdrive signal in addition to the buzzing noise, would there be v+ in the audio path?
Have you tried with a probe where the buzz starts? I've found bad working opamps and transistors that way fairly quickly.
Recently in a Solaris build the transistor was broken that was in the part where the transformer was located. I had to order the transformer and had already build the pedal which was fully working until I switched to the transformer part after I received the transformer and installed it on the PCB. With the probe I quickly discovered that the transistor added a buckload of noise and reduced the output volume. So swapping that one fixed it.
I hope this turns out to be a similar issue for you!
Recently in a Solaris build the transistor was broken that was in the part where the transformer was located. I had to order the transformer and had already build the pedal which was fully working until I switched to the transformer part after I received the transformer and installed it on the PCB. With the probe I quickly discovered that the transistor added a buckload of noise and reduced the output volume. So swapping that one fixed it.
I hope this turns out to be a similar issue for you!
I had a similar sound recently with a frog preamp. Different circuit, but the solution for me was to reflow the valve socket - I had initially done it when I was really hungry and a bit shaky, and in hindsight all of the joints looked OK, but some didn't really have as much solder as would be ideal. Reflowed them all and added solder and the problem was gone. I would be carefully checking all the soldering.
comradehoser
Well-known member
After visual inspection, audio probe is the way.
jimilee
Well-known member
I’m waiting on a few replacement parts. I will probe next. The reason I didn’t do it yet is because on the last one, it was somewhere around the diodes. I’m getting the proper diodes instead of a substitution.
comradehoser
Well-known member
I am definitely not an expert, but I would suspect so. Maybe a fault/soldering on a coupling capacitor?
I agree with the idea to run an audio probe. It might be the most definitive diagnosis.
jimilee
Well-known member
I’ve reflowed about three times. All the parts are checked and checkout. I’m pretty sure it’s a part. This is the second time I built it, and I used a few of the same pieces from the last build. I got the same buzz on that one, too.
