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January 22, 2019, 09:23:35 pm

Author Topic: Scratching sound in left channel  (Read 150 times)

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Offline Kurjok

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Scratching sound in left channel
« on: January 07, 2019, 06:05:25 pm »
Hello!

I completed my crack and have listened to it for a couple weeks with no issues. I installed the speedball a couple weeks ago and it was dead quiet until now. I am experiencing a quiet scratchy white noise in the left channel that does not increase with volume. Sometimes it goes away as well but is present more often than not. It persists even with no source connected. Any help is appreciated!

Thanks!

Offline Paul Birkeland

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Re: Scratching sound in left channel
« Reply #1 on: January 08, 2019, 04:56:07 am »
It is possible that during the Speedball installation, some joints in the original build that weren't all the way solid are now a bit noisy.  What we recommend is to plug a pair of inexpensive headphones into the Crack while it is running, then poke around the circuit with a wooden chopstick until you are able to activate the noise by poking somewhere specific.  That will tell you where to focus your efforts. 
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Kurjok

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Re: Scratching sound in left channel
« Reply #2 on: January 10, 2019, 08:43:55 am »
I should also add when I installed speedball one of my insulators cracked, and I replaced it by cutting a piece of plastic in the exact same shape with a hole. Would this affect the left channel?

Offline Doc B.

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Re: Scratching sound in left channel
« Reply #3 on: January 10, 2019, 09:06:49 am »
If you mean the insulator between the transistor and the heat sink, yes, using a different material can be a problem. The insulating material must have a reasonably good heat transfer characteristic. They are generally made from mica or from a silicone based material with reasonably good thermal conductivity. A lot of plastics have really poor heat transfer characteristics. If that is the case the heat sink will not be able to wick the heat and the transistor will overheat after a short period.
Dan "Doc B." Schmalle
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Bottlehead Corp.

Offline Kurjok

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Re: Scratching sound in left channel
« Reply #4 on: January 10, 2019, 02:38:49 pm »
I just tested this by turning on the amp with my headphones on and the noise is present right away now. I will poke around this weekend when I have time to see if I can narrow it down
« Last Edit: January 10, 2019, 02:45:15 pm by Kurjok »