Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: arugula on October 16, 2021, 03:01:20 PM
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i have a noticeable crackle static in both ears and get hum when the volume is turned above about 1 o'clock. This is with no DAC connected to the Crack. Have not installed the speedball yet and all resistance checks etc tested out OK. I redid all the solder joints twice. After the first time, the hum went away but the crackle did not. After second time crackle remained and hum became worse than before. Tried deoxit on the tubes. I had burned the insulation a bit on one of the RCA female jacks so I replaced them. Found Doc's post about the black wire on the headphone jack so did this extra carefully.
Not sure what to do next. Is it still possible to send it in for you to look at it? I really do love the sound. Would like to get this first part in good shape and then try the speedball. After all this 'practice' have become much better with soldering, but I assume I messed up some component or joint the first time around.
Thanks a lot for your help in advance.
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Can you post some build photos? Maybe there's something we can spot.
How much is the Crack turned up with the pot at 1 o'clock? Is the noise there with your DAC connected?
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been trying to reply - thanks for getting back to me. perhaps I tried to post too many pictures. I will continue to work on getting the pics up, but in the meanwhile: the hum becomes audible when pot is about halfway up. When it is at 2/3 the hum is really loud. When I turn on the DAC the hum is essentially gone! Can be heard only when pot turned almost all the way up, and then is faint.
Will work on those pictures...
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turning the DAC on makes the hum go away, but not the crackling sound. Here are just a few pics.
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more pictures, just a few at a time
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One of the black wires on your headphone jack is not captured by solder.
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The diode lead poking through 19L needs to be trimmed back.
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Is it normal to get the hum when the DAC is not plugged in?
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If the volume control is turned up with nothing plugged into the inputs, some noise is normal.
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thanks much. will try the soldering fixes you recommend.
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I tried desoldering the connection you mentioned and also clipped that wire. Took a while as I was tied up at work. It may have made some difference, but there is still a static in the right ear, with an occasional pfffft sound. does it help me narrow things down that it is in the right ear. I really appreciate your looking at the images and telling me where there are potential errors. I took some better close ups of different sections, posted below.
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and some more...
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The solder joint at 3L looks like it hasn't been well flowed out.
A strategy that can be helpful is to take a wooden chopstick and run the amp with some cheap headphones plugged in, then poke around the circuit to see if you can create the noise by poking something specific, then you can focus your efforts there.
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thanks again - will give that a shot. am thinking about trying to do major parts of the circuit. can i order the wire and most of the parts on an individual basis? or maybe a set of just the circuit components? a bit too early for that but am beginning to think this will happen.
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I'm not seeing anything there that would convince me that you need to start over.
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good to hear! I am determined to get this thing to work - for one thing the sound is just amazing and I have a great time despite the lightning sound effects in the background of my music. Will approach this one segment at a time and redo/replace parts until I get it. First try the chopstick trick. Thanks million for your help.
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The solder joint at 3L looks like it hasn't been well flowed out.
A strategy that can be helpful is to take a wooden chopstick and run the amp with some cheap headphones plugged in, then poke around the circuit to see if you can create the noise by poking something specific, then you can focus your efforts there.
Good day sir, would like to ask how to do the chopsticks procedure. Do you flip the chassis on it's back, plug a pair of cheap headphones under the wooden housing and plug a dac/source to the RCA, and then poke around with the chopsticks on all the joints to find where the problem is (I assume if there's a crack then I would re-solder/re-flow that particular joint? Am I getting it right? Thanks.