Loud buzzing, crackling and popping on standard Crack [resolved]

[jamesad1994]

Hey all. I assembled my Crack around February this year, and I have yet to add the Speedball kit. In the beginning, I had zero issues with noise, but it has gotten progressively worse. Now its to the point where 70% of the time there is a lot of buzzing and other noises coming through the amp and its hard to enjoy this otherwise awesome kit.

My setup consists of the non-Speedball Crack sourced from a Topping D30 to my PC via optical, using the HD650's. The issue seems to stem from the 1/4" jack and the 12AU7 tube connection, because the popping/crackling sound can be altered and sometimes (temporarily) fixed with a loud pop whenever I jiggle the tube or the 1/4" connector of my headphone cord. The intensity of it disregards the volume setting of the amp; it is always loud.

Any idea how I can troubleshoot this issue? This was my first soldering experience and while I thought I did a decent job, I'm sure I messed up a joint or two. Whatever it may be, I would love to enjoy my kit once again!

Thanks all,

James

[Paul Birkeland]

If the noise changes when you tap on the Crack or wiggle connections, you have a bad solder joint.  It is extremely common for a Crack exhibiting these symptoms to have a loose black wire on the headphone jack that isn't soldered. 

Another method to pinpoint other issues is to use a wooden chopstick to poke around the amp while it's running with a pair of cheap headphones on.  When you find the problematic joint, you should be able to generate a pop by poking at said joint with the chopstick.  This also gives you a good excuse to get some tasty takeout. 

[fromnowon]

This also gives you a good excuse to get some tasty takeout. 

Ha ha, I liked that!  Helps to have a sense of humor!

[adydula]

I would check the red leds soldered tothe 12Au7 as well...if you can carefully turn the assembly upside down, to be able to look at the leds while slightly moving the small tube and see if this popping occurs and does one of those leds go on and off etc...

I had this issue where one of these leds several weeks after going thur tube changing a looud popping sound started happening.....but the volume went down on one channel as well...I replaced the leds and put some bend in the leads to allow for some stressrelief...

FYI
Alex

[jamesad1994]

Thanks for the tips, guys! I'll be sure to put some work into it tonight and see how it goes. Also, I loved the takeout comment; I'll be sure to try out the new Chinese place! 

James

[jamesad1994]

Wow, I totally forgot to update. Before fixing the Crack, I had to go buy some soldering equipment that I misplaced during my recent move. I only really got to repairs a few days ago.

Before fixing the Crack, I had to go buy some soldering equipment that I misplaced during my recent move. I went ahead and bought a solder pump since I knew I made some other mistakes with my first solder experience. The main issue was the black wire leading from the power supply to the headphone jack terminal, but I found a handful of joints that I really wanted to touch up including the ground lug terminal (one of the first joints, heh). Now, it sounds better than ever! I'll get around to installing the Speedball whenever I know for sure there isn't another issue with the main kit. 

Thanks again folks!

James

[hoy83]

Is this thread still alive? I was thinking of not starting a new topic since I basically have the same problem, slight crackling and static at random moments in a song. Can I use a pencil instead of a chopstick to probe the wires? So I'm guessing the unit has to be turned on and connected to an audio source while probing the wires? Sounds dangerous.. but I'll try to give it a try.

ps. just read doc B's pinned post, it seems I'm not the only one, just to clarify as well, as doc b said, I should reflow ALL solder joints?

[Paul Joppa]

"... is this thread still alive?"  It is now!

Yes it must be turned on and operating fro this test. I avoid using pencils because the "lead" is graphite and conductive. There are two reasons to use a non-conductive poker - you don't want to shock yourself, and you also don't want to accidentally make a short between two adjacent terminals. Some of them are really small and close together ...

The reason for touching up all solder joints is that it is much faster that determining which ones really need to be touched up.

[hoy83]

So I do need to re-solder ALL joints then..?

[Paul Joppa]

Well, you can do them one at a time, checking after each one whether the amp is working correctly.  :^) 

[Paul Birkeland]

Reflowing all the joints other than the power switch and where the LEDs mount is a very good idea.

[hoy83]

Hi good day, just an update on the cracking/popping issue of my bottlehead crack. I followed this https://forums.stevehoffman.tv/threads/otl-headphone-amp-makes-popping-noise.1031171/ and it seems to work. Although at times I get some cracking but it significantly lessened to almost no static at all..

[kGlerup]

Hi good day, just an update on the cracking/popping issue of my bottlehead crack. I followed this https://forums.stevehoffman.tv/threads/otl-headphone-amp-makes-popping-noise.1031171/ and it seems to work. Although at times I get some cracking but it significantly lessened to almost no static at all..

So... You found a way to avoid or lessen the problem, without fixing the main issue?
A Crack should be quiet without noise or crackling sounds. I had a bit on my own one as well. Used the chopstick method and quickly found the faulty joint.

[hoy83]

yeah I think.. how do you go about the chopstick method..? you plug in a pair of headphones, turn the chassis upside down and connect it to an audio source, then prod the joints while it's running? if there's static that's the joint you got to re-solder?

[kGlerup]

You are correct.
This is one-handed testing with a chopstick. Other hand on the back.
Plug it to a source, but don't play music. You just want silence.
Then poke the joints. If one is faulty, then you will hear it