Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: axg20202 on December 11, 2016, 10:49:44 AM
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I'm getting these strange noises from my crack (stop sniggering at the back, Smiggins). I'm pretty sure this only arose after installing the speedball kit. Amp sounds great otherwise and is fully functional, but randomly every 20 seconds or so I get these little pops and fizzes, then back to silence again for a bit, then some more pops. The level of the noise is independent of the volume control and occurs with no source connected. I've tried different tubes and its not that. I've also reflowed all the solder joints and that didn't fix it, so now I'm wondering if there are some dodgy components. Can anyone suggest what to try next?
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Is it gone when a source is connected? Is your Crack connected to ground properly? Are your wall sockets connected to a ground?
Did you test the joints using chopsticks?
Voltages checked?
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Is it possible to restore it to the stock Crack form and see if the problem persists?
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Maybe cell phone or other RF noise?...John
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This is very likely noise from a wireless device (cell phone or wifi router).
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Thanks all. I'll keep investigating. The amp produces the noise regardless of whether a source is connected or not. Could be interference or mains power noise. I will try it in different locations. I do sometimes suffer from mains noise in my studio, which is why the Crack is connected to my power conditioner. Strange that I didn't notice it before the Speedball upgrade. I'm definitely not reverting to stock Crack until I've tried everything else. I do wonder if faulty power or output caps could cause this? By the way, the noise appears to be present equally in both channels. If it was in one channel only I'd have something to go on!
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I'm now pretty sure the headphone output jack is the culprit. Pretty relieved it's something simple. Annoyingly, they are the only solder joints I didn't reflow. However, the jack is not great quality and when connected there is a lot of flex in the jack, so I think it is actually faulty. I think I will replace with a higher quality alternative.
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It's quite possible that there is flexing the jack because the terminals were overheated when soldering and the terminals became loose. Bear that in mind when installing a replacement.
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It might be helpful to see a photo of your headphone jack.