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February 24, 2020, 04:14:27 AM

Author Topic: Crackling noise  (Read 238 times)

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Offline triode

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Crackling noise
« on: December 14, 2019, 12:51:18 PM »
Hi

Lately my Stereomour (45 tube config) making some crackling noise. Its not so loud but getting louder now. It was in left side only in the beginning, but now the right side also has the same noise, sometimes even louder.

I changed all the tubes (driver and output tubes) and it still crackling, also change input source, and the noise still there.

Would this because of the MJE5731A going bad ? I used 6829 tubes as driver for some time, would this taxed the MJEs too much and they given up prematurely?

Thank you for your help

Regards

Offline Paul Birkeland

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Re: Crackling noise
« Reply #1 on: December 14, 2019, 12:57:41 PM »
Lately my Stereomour (45 tube config) making some crackling noise. Its not so loud but getting louder now. It was in left side only in the beginning, but now the right side also has the same noise, sometimes even louder.
Have you moved any wireless devices close by in the recent past?  Your issue could be external interference.

Would this because of the MJE5731A going bad ? I used 6829 tubes as driver for some time, would this taxed the MJEs too much and they given up prematurely?
Do they looked cooked?  I checked out the data on the 6829 tubes and I don't believe they will cause problems.  A DC voltage check will tell you a lot about the health of those devices, and if they are being worked too hard they will char the PC board.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline triode

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Re: Crackling noise
« Reply #2 on: December 14, 2019, 05:10:37 PM »
Thanks for the reply

I did check a DC voltage check. All looks good IA/IB around 370-380V, IO/IA around 200V , KReg around 2.5V
I just connect the speaker again and the crackling noise much less now ! Only occasionally in left channel and not so loud.
No Idea what happened !!!

Maybe I'll check solder connections latter in Christmas/New Year break

Thanks

Offline Paul Birkeland

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Re: Crackling noise
« Reply #3 on: December 15, 2019, 05:35:00 AM »
Yes, it sounds like perhaps reflowing some joints would be a good idea.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline borism

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Re: Crackling noise
« Reply #4 on: January 30, 2020, 08:14:24 AM »
I just connect the speaker again and the crackling noise much less now...

I wonder if just cleaning the speaker binding posts, speaker wire connectors and RCA connectors might help with the issue.
Boris

Offline triode

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Re: Crackling noise
« Reply #5 on: February 15, 2020, 07:29:51 PM »
Paul,

After refreshing some solder joint, the crackling noise happened less time. But still comes back from time to time

I want to check if this comes from power stage or driver stage. Could I turn-on Stereomour without driver tube ? Would this harms the amp?
If there is no noise, then logically the noise comes from driver stage. Would this works?

Thanks

Offline Paul Birkeland

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Re: Crackling noise
« Reply #6 on: February 16, 2020, 04:50:43 PM »
You can run the amp with no driver tube, sure.  If the noise does not appear without the driver tube, that doesn't tell you that it's absolutely the driver tube, it just tells you that it's not related to the 2A3 output stage. 

Does the amp do this with nothing plugged into the inputs?  Are you feeding the amp straight from a PC, or are there wireless appliances super close to the Stereomour?
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline triode

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Re: Crackling noise
« Reply #7 on: February 16, 2020, 09:01:55 PM »
Thanks Paul

The amp is connected to the Foreplay III and then the source.
I got no noise when I use Paramount amp instead, so I guess that would rule out the upstream component as source of noise.

I will try if there is no noise when no driver tube installed. At least we know if the noise comes from not the output stage or not.

Next I will try with all tube installed but no source connected

Regards