Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Oddvar on October 27, 2016, 07:11:05 am

Title: AC30 disaster?
Post by: Oddvar on October 27, 2016, 07:11:05 am

Hi again.  I have build the AC30 by Hoffman, and i worked just fine.  There hase been many issues, but they were fixed.  Today though, the wholde amp started to act microfonic, every single item makes noise, crackling as H##l.  I have checked it all and I am not understanding what possibly could cause this?

Title: Re: AC30 disaster?
Post by: uki on October 27, 2016, 07:47:03 am

Quote from: Oddvar

... started to act microfonic ...

That could be a bad tube.

Title: Re: AC30 disaster?
Post by: Oddvar on October 27, 2016, 08:57:41 am

It's very strange.

Title: Re: AC30 disaster?
Post by: sluckey on October 27, 2016, 10:20:41 am

You may be jinxed.

Title: Re: AC30 disaster?
Post by: Oddvar on October 27, 2016, 10:41:42 am

It was the 10k resistor going from the middle pin on the basspot to ground.  Problem solved.  What could cause that?

Title: Re: AC30 disaster?
Post by: shooter on October 27, 2016, 10:46:47 am

Quote

What could cause that?

see reply #3 :icon_biggrin: