Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: wiener4hire on May 22, 2014, 04:46:10 AM
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Before i begin i'd like to say i am a complete nube, this is the first soldering i have ever done.
So i just recently got my Crack up and running, haven't installed the speedball i got with it yet though. There is however a buzzing noice coming through the headphone. It is primarily in the left ear, but is also present in the right ear to a lesser extent. It doesn't matter how loud the volume is, and is there both when playing music and not, it is loud enough to be a constant nuisance. Anyone have any idea why this is?
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Just adding that the buzzing is a very low frequency, probably around 50 hz.
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Were the voltage and resistance checks all within the limits?
Does the buzzing persist with a source plugged in?
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Both were within the limits yeah. I did however not do the final test with the jack itself, simply because i couldn't quite figure out what exactly they wanted me to do. I just plugged in some cheap headphone i had lying around, and it made the buzzing sound. Same with other headphones. And it also persists when plugged in.
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What is your source chain?
If you are using a pc or dac streaming try connecting by usb instead also try a different source completely such as a cd player, record player to see if the noise is still present.
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My source chain goes USB -> Aune T1 -> RCA -> Crack -> HD 650.
I jsut tested from a CD player, and it was the exact same. I noticed something odd though. When i was about to power the Crack off, i was still wearing my cans, and my hand just touched the big tube. That changed the buzzing significantly. When i touch the tube it gets a lot louder, but it doesn't do anything when i touch the smaller tube. Don't know if that helps.
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OK the cd player was direct to the Crack without the dac in the chain? Can you try putting a few twists in your rca cables that connect the dac to the Crack and listen again the Crack is very good at picking interference from wifi routers and other electrical equipment check the routing of your cables try and route any power leads away from your RCA interconnects. This should help eliminate some of the possible basic external causes and the Bottlehead team will help on anything that might be internally related.
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Yeah, the DAC was not in the chain. I don't really get what you mean by "Can you try putting a few twists in your rca cables that connect the dac to the Crack and listen again"?
I also tried moving it to another room with the CD player, and it was the same. I doubt outside interference is the problem.
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Try removing the 6080 and cleaning the pins with something like a scotchbrite pad or with Deoxit. It might just be flaky contact.
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Yeah, the DAC was not in the chain. I don't really get what you mean by "Can you try putting a few twists in your rca cables that connect the dac to the Crack and listen again"?
I also tried moving it to another room with the CD player, and it was the same. I doubt outside interference is the problem.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fcdn.head-fi.org%2F7%2F7a%2F900x900px-LL-7ab2aec2_0092.jpeg&hash=3e0ef8569287b83ec1fec5d7e3f8b0b88ec0a737)
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Unfortunately i have none of that on hand, i can get it soon though. I just unplugged the 6080 and took these two pics of the pins, do they look good?
http://imgur.com/hZ4qLXQ
http://imgur.com/fhMWdpV
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Unfortunately my RCA's are cheapo cables like shown in the pic i linked below so i doubt that will do much. Do you think the cables could be the problem?
http://imgur.com/stdMSYI
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You could try moving them around while listening and see it the buzzing changes or stops momentarily whilst doing so. If it doesn't change then it most probably isn't the cables.
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Tried that already, and it didn't do anything.
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You may have a bad solder joint that is causing the noise, or you may have pins on the tubes that need to be cleaned. Try reheating any suspicious looking solder joints, particularly those associated with the 6080 socket and, as I have already suggested, try cleaning the tube pins.
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I'll try and clean the pins tommorow when i can get what i need. I'll also check if there are any bad spots. I did just see this after unplugging the 6080 however:
http://imgur.com/m6F8z5l
As you can see some of the pins inside the socket look bent, could this be the issue?
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The socket forks are free floating and will shift around as you insert a tube. If the 6080 will go all the way into the tube socket, they are very likely doing their job.
Pin 7 potentially looks like one of the fork pins has been bent out of position, but it's hard to say from the photos. If pin 7 wasn't working, the 6080 wouldn't glow.
-PB
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I have a buzzing from one channel only (much weaker in the other) that swaps channels when I swap the valves in my S.E.X. 2.1 from one channel to the other. Mr. Joppa suggested that it may be a condition affecting the cathode to heater coupling due to poor insolation. He recommended that I run these valves for 50 - 100 hours and see if that will quiet them down. He can't explain it but says sometimes it seems to do the trick.
I know there are many differences between the Crack and the S.E.X., such as 6DN7 valves (1 per channel) vice only one 6080 valve for both channels. You don't have the option of swapping channels to try and isolate the offending valve.
For JP, Paul, Doc B., and others: Is this a possible source of the buzzing the OP is experiencing?
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I had buzzing in my crack that was caused by a bad (stock) power tube. Once I swapped it out, the buzzing stopped.