Finished Crack - Weird popping sound [resolved]

[CmdBrewsky]

Hi guys

I finished my crack a couple of weeks ago however as I was getting weird interference through my PC audio card I was waiting for a DAC so that I can use the optical out of my PC to get rid of the interference.

Anyway, as I finally had a chance to listen to the Crack without any interference it sounds really great, however I have a few questions. First, if I move or hit the table on which the Crack is on, there is a loud pop. The harder I hit the table, the louder the pop is, and I was wondering whether this is normal or if there is something I have done wrong in the soldering? So if I don't move anything it's fine there is no popping sound, however if I put my glass of water for example on the table and this would cause a pop. Sometimes even when I am typing on my keyboard would make the Crack pop. Is this a problem with my soldering or? I was planning to reheat some of the solder points however I wanted to ask whether you can help me pinpoint the issue so I can save me some time.

It might be something to do with the headphone input since if I rotate the headphone jack while its inserted in the input, it makes similar popping/interference sounds. Maybe some of the wires on it aren't properly soldered or is this normal? If I hold the cable and the jack in place with one hand and don't move, everything is fine, but otherwise if the cable moves  in any way, there is this "static"-y type of sound and a bit of popping.

Also there is a small background low pitched hum, but this might be due to the electricity especially in summer when every apartment in the surrounding area is running their A/C and the power grid is under a lot of strain. The hum is constant and doesn't change with lowering or increasing the volume, but it doesn't bother me since you cant even hear it, even when playing acoustic instrumental songs. But just trying my luck maybe there is an easy fix, so while I am here, I might fix this as well.

So before I go ahead and use it regularly I wanted to know if there is any way to fix these issues, especially the one with the headphone input since the other one could be theoretically solved by just putting the Crack on another table next to my PC table.

[Paul Birkeland]

I was wondering whether this is normal or if there is something I have done wrong in the soldering?

That's a loose connection/poor solder joint.  When you jostle it, it loses connectivity momentarily and pops.  Often times to find these joints, one would poke around in the running amplifier with a wood chopstick to be able to irritate and locate the proper joint.

Also there is a small background low pitched hum, but this might be due to the electricity especially in summer when every apartment in the surrounding area is running their A/C and the power grid is under a lot of strain. The hum is constant and doesn't change with lowering or increasing the volume, but it doesn't bother me since you cant even hear it, even when playing acoustic instrumental songs. But just trying my luck maybe there is an easy fix, so while I am here, I might fix this as well.

This hum may actually resolve itself when you fix the popping, but a lot of motors on the same AC mains circuit could also make for a noisy powerline.

[CmdBrewsky]

I tried re-soldering the headphone input and it still has the weird cracking noise.

However now there is this weird seemingly random noise coming, it sounds like crumpling paper and now an even bigger problem. Sometimes after a random loud pop, all sound is lost, and if I slightly tap anywhere on the crack itself, on the wood from the sides, there would be another loud pop and the sound would come back.

So if I had to sum up the current problem: Sometimes there is a random noise (similar to crumpling paper together with some light interference (TV snow) sound possibly, I dont know how else to explain it) that isn't connected to anything that I could find out - I tried different power outlets at two different locations and still the random crumpling noise and it just happens at random points, couldnt pinpoint anything like moving the headphones cable or touching the Crack etc.

And the second problem is the extremely loud/popping noise that happens when I either touch the table on which the Crack is on, or lately when I lightly tap the Crack on the sides which sometimes ends up somehow shutting the amp (at least the sound) until I tap the amp or the desk again. It is really weird, and in the back everything seems fine and the voltages and resistances were correct when I assembled and checked them.

[Paul Birkeland]

However now there is this weird seemingly random noise coming, it sounds like crumpling paper and now an even bigger problem. Sometimes after a random loud pop, all sound is lost, and if I slightly tap anywhere on the crack itself, on the wood from the sides, there would be another loud pop and the sound would come back.

This is the exact symptom of a bad solder joint.  It also indicates that said bad solder joint is not likely to be on the headphone jack.

[Doc B.]

I suggest going over the circuit with a magnifier, inspecting every joint. You will find an unsoldered connection in there somewhere.

[CmdBrewsky]

Yes! Thank you guys!

After a thorough inspection I found the loose connection, resoldered it together with some solder joints that looked like they could use some extra solder, and now everything is fixed. No popping at all, and even the low background hum that I thought was due to dirty power is gone.

Everything is excellent now, thanks for the support and help.

[adydula]

Great!

Thats a good feeling to have that one behind you!!

Enjoy the music now!

Alex

[Paul Joppa]

...and... Doc B gets to keep the corner office for another month!