Constant Crackling noise

Philip_dop · 350

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Offline Philip_dop

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on: March 05, 2021, 06:04:31 AM
I built my crack a while back.

Now it seem like a problem has started, it crackles quite a bit now where it's unusable.

I've check the resistance and found some issues but not sure what is the cause.

When testing resistance,

Pin 7 and 9 show OL, sometimes it shuts off my voltmeter.

and then pin 13 is also OL doesn't change

I've checked all the solder joints they are solid from what I can see.

It was working fine for a while then this just started.

Please advise

Thanks so much




Offline Paul Birkeland

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Reply #1 on: March 05, 2021, 06:14:59 AM
Does your Crack have a Speedball?  If so then the  resistances at 7 and 9 won't be 3K (since you pulled out the 3K resistor to install the Speedball).

How are the voltages?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Philip_dop

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Reply #2 on: March 05, 2021, 06:28:48 AM
the voltages are 5-10 volts over.

And yes I do have a speedball kit on it.

Thanks for the help Paul.



Offline Paul Birkeland

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Reply #3 on: March 05, 2021, 06:29:27 AM
Can you post the voltages for terminals 1-10?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Philip_dop

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Reply #4 on: March 05, 2021, 06:41:27 AM
1 76.6
2 180
3 0
4 176.8
5 89
6 3.5mv
7 101
8 .7
9 106
10 0



Offline Paul Birkeland

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Reply #5 on: March 05, 2021, 06:44:39 AM
If you tap on either tube or the chassis plate, does it change the crackling?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Philip_dop

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Reply #6 on: March 05, 2021, 06:48:36 AM
yes it does, if i tap the volume knob side it either stops or crackles a bit more.

if i hold the plate down it stops
« Last Edit: March 05, 2021, 06:50:36 AM by Philip_dop »



Offline Paul Birkeland

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Reply #7 on: March 05, 2021, 06:50:21 AM
That would tend to suggest that you have a solder joint in the amp that isn't 100% functional.  Reheating all the joints will very likely make this issue go away.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Philip_dop

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Reply #8 on: March 05, 2021, 06:51:08 AM
Thanks So much Paul, I'll try that and let you know.