Low level Crackling -Help

dcham · 2970

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Offline dcham

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on: December 04, 2013, 07:51:59 PM
Hello,

After almost a month of using the Mainline. I hear crackling (frying?) sound. Not constant but low level, coming in and out. Seems to have nothing to do with volume levels or inputs as the crackling noise still appears at the same level with volume turned all the way down and nothing connected to the inputs. It does not get louder as you turn volume up.

Want to trouble shoot but need somewhere to start. This appears even when unit has been on for a long time. Tried cleaning tube contacts, still no difference. This has gotten worse over the days.

Any help will be appreciated.

Dennis



Offline galyons

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Reply #1 on: December 04, 2013, 08:10:53 PM
Sounds like a bad solder joint to ground.  Reflow them.

Cheers,
Geary

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Offline dcham

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Reply #2 on: December 04, 2013, 09:01:17 PM
Thanks will try that Geary!



Offline Grainger49

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Reply #3 on: December 05, 2013, 02:01:18 AM
If that doesn't cure it, or maybe before, try removing and reinserting the tubes 10 times each. 

It could be that the socket or tube pins are a little dirty.



Offline dcham

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Reply #4 on: December 05, 2013, 02:44:21 AM
Thanks will try that tomorrow. My tech scheduled with me to trace his solder joints next week.

To add the noise sounds like a soft ticking like a helicopter but higher pitch. Other times you get crackling like a dirty switch but unlike a switch you still hear audio clearly and it does not cut out. Problem is also stronger on left ear than right.

Hope these clues add some light to my problem.

Best,
Dennis
« Last Edit: December 05, 2013, 02:54:40 AM by dcham »



Offline Paul Birkeland

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Reply #5 on: December 05, 2013, 03:38:45 AM
Are you 100% sure it's not your cell phone interfering with the amp?  This could also be power line grunge from an appliance getting through.  In either of these cases, it would be most likely that the noise would be intermittent. Is your situation constant noise, or just sometimes?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline dcham

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Reply #6 on: December 05, 2013, 04:55:05 AM
I think it is not a cellphone as I know what that sounds like. Also the noise is constant. I usually can mask it by turning the volume of what I am listening to up.

The Mainline is plugged into a dedicated power line where all my gear is plugged into. I have no problems on the mini phone jack of my computer, nor the cheap NuForce amp which the Mainline replaced. Hoping my tech can figure it out. Hopefully at worst a bad tube.

To add the noise is not affected by the volume attenuators. It is still there when volume is off. Also noise does not get louder when I turn up volume. It also remains when I unplug all inputs and switch between the two inputs. Strange.
« Last Edit: December 05, 2013, 05:09:10 AM by dcham »



Offline Doc B.

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Reply #7 on: December 05, 2013, 05:10:03 AM
I would have responded the same as PB, most likely it is an outside source. Also check the all the film caps to be sure that the bodies of none have been damaged by a hot soldering iron. A melted spot on a cap body can create a short in the cap that results in a constant charge/discharge that can make a tick-tick-tick sound.

Dan "Doc B." Schmalle
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Bottlehead Corp.


Offline dcham

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Reply #8 on: December 05, 2013, 02:15:52 PM
Tried popping tubes in and out several times as per suggestion. Seems to have gotten rid of the noise. Funny that was the first thing I tried before even starting this thread. Did not work the first time, but I guess this time it did. Let's see. Usually from my experience, such noises are something as simple, a poor connection or a worn contact. Being in Manila it is extremely humid here.

Trying to eliminate as many possibilities, if it comes back I'll post again. Hopefully this solves it.

A big thank you to everyone in the community for your help and suggestions.

Dennis
« Last Edit: December 05, 2013, 02:18:14 PM by dcham »



Offline Grainger49

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Reply #9 on: December 05, 2013, 02:40:24 PM
It sounds like the tube or socket was dirty.  But if it comes back it might be one of the tube pins solder joints.  Re seating the tubes might have moved the bad joint.