[HAM] B3 Swell Capacitor

[David Anderson]

Jordan,

It sounds like your swell capacitor or something in the box is acting  
as a capacitor microphone.

I don't want to patronize, just cover all the bases, but when you say  
that the range of travel is correctly adjusted, I assume that you  
mean that the maximum expression pedal position is adjusted for  
maximum output from the preamp, not maximum range of mechanical  
movement. The mechanism will move past the point of maximum output  
and will cause noise at that point. I set mine by watching the output  
on an AC voltmeter.

It's not that hard to take the swell capacitor housing cover off to  
make sure something hasn't worked loose. Also, check the screws  
underneath the preamp that hold the ring terminals to the swell  
capacitor contacts. I have seen these looser than they should be.

I tried tapping the housing on mine and heard no noise through the  
speakers.

David A.

On Feb 9, 2008, at 10:00 AM, Jordan Kersten wrote:

>
> It is not a microphonic tube.  When the swell box is all the way  
> up, you can tap on the tubes lightly and get to noise.  Tap on the  
> swell box with the same amount of force, you can hear the taps and  
> it will start to ring and have a low frequency feedback kind of  
> sound and it will ring like this until you turn the pedal down.  It  
> won't ring until it senses vibrations from the cabinet and it won't  
> do it when the pedal is anywhere but in the full up position.   
> Adjusting the link between the swell capacitor and the foot pedal  
> didn't work.  Does it seem like something is loose in there?