kross 0 Report post Posted August 23, 2006 I had the pot connected to the pcb ground and it had the buzz and so I removed the connection but the buzz is still there. The pot is not isolated and so is connected to the mains earth. And I was wondering if the connection of the pcb ground to the mains earth is a problem or not. Anyway, I am puzzled by all this and will find time to slowyly try different things to see if there is any difference. Thanks. maybe you can try to decouple the pcb ground to the mains ground through a cap instead... Share this post Link to post Share on other sites
heady 0 Report post Posted August 23, 2006 Thanks kross. What kind of caps and value? I have no idea. Share this post Link to post Share on other sites
kross 0 Report post Posted August 25, 2006 maybe a big value ones...i tried before 47000uF. but you can just try any caps and see whether the whizz go away..just soft bind them will do...don't work still can take away easily. Share this post Link to post Share on other sites
huangyong 0 Report post Posted August 25, 2006 wow.. kross.. that's capacitve ground coupling. used in medical equipment.. Share this post Link to post Share on other sites
huangyong 0 Report post Posted August 25, 2006 this one for you heady, posts:888 Share this post Link to post Share on other sites
heady 0 Report post Posted August 25, 2006 Wow, didn't know it myself Share this post Link to post Share on other sites
heady 0 Report post Posted August 26, 2006 Latest is, the problem solved itself! Actually, it was my mistake... What happened was when I tested the PPA outside its enclosure, it had the hum. After I cased it, there was some problem as the right side faded out after about 4 hours of running in. I strip everything and could not find any problem. I finally decided it must be a loose connection somewhere. When I case the amp the second time, I forgot to attached the ground wire to the volume pot. When I realised this and re-connected it, the hum stop. Now I am waiting for a nicer knob to fit to the pot. Thanks to all. Share this post Link to post Share on other sites
