Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Leevi on May 07, 2016, 02:45:39 am

Title: Crackling tube when warming up
Post by: Leevi on May 07, 2016, 02:45:39 am

This problem has happened now and then.
What is the reason for this and is it telling about a bad quality of the tube?
Normally the crackling tube works fine after it has properly warmed up.


Leevi

Title: Re: Crackling tube when warming up
Post by: HotBluePlates on May 07, 2016, 10:20:54 am

I don't know, and would tend to keep using the tube unless the crackling continued after the tube warmed up. I'll trust you've verified the sound is definitely from the one tube.

Is the tube old? Could the pins need cleaning with some DeOxit? Are the pins narrow and fit loosely in the socket?

Just throwing out some ideas for things you could check.

Title: Re: Crackling tube when warming up
Post by: sluckey on May 07, 2016, 10:26:49 am

I've seen that before. After verifying it was the tube causing the crackle, I bent all the tube pins and threw it in the trash.

Title: Re: Crackling tube when warming up
Post by: Leevi on May 07, 2016, 11:00:20 am

Quote

Is the tube old? Could the pins need cleaning with some DeOxit? Are the pins narrow and fit loosely in the socket?

Quote

After verifying it was the tube causing the crackle, I bent all the tube pins and threw it in the trash.

I have limited the problem by changing the tubes to one particular tube which is brand new as the amp as well.
I strongly believe that the problem is caused by the tube, not by a bad contact or something else.
I have even tested the problematic tube with another amp and the problem was there as well.


I have not found any sound related issues after the tube is properly warmed up.


/Leevi

Title: Re: Crackling tube when warming up
Post by: HotBluePlates on May 07, 2016, 11:20:40 am

Quote from: Leevi on May 07, 2016, 11:00:20 am

... I have limited the problem by changing the tubes to one particular tube which is brand new ...

Return the tube to the vendor for replacement.

Title: Re: Crackling tube when warming up
Post by: Leevi on May 07, 2016, 12:25:16 pm

Quote

Return the tube to the vendor for replacement.

Yes I do it


/Leevi

Title: Re: Crackling tube when warming up
Post by: Paul1453 on May 10, 2016, 01:37:56 pm

My Airline amp just started making crackling sounds when I turn it off.
You know how the sound takes a few seconds to die out.
After switching off I now get a pop and a dull crackling as the sound dies out.
I thought it might be my output tubes, but swapping them made no change.
Now, I'm thinking it might be my tube rectifier or my 6AU6 preamp tube.

No weird sounds as it warms up, only when shutting down.
My stuff is not new and I'm not too concerned about this new noise.
I just thought I'd mention my crackling issue. :icon_biggrin: