prodj101 Posted October 31, 2002 Share Posted October 31, 2002 I was just wondering if any of you know how to make an amplifier virtually hum free. thanks in advance. Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted October 31, 2002 Share Posted October 31, 2002 Heh.... it's called paying attention to your wiring layout and grounding. You could be suffering from a ground loop, a bad solder joint, or poor wire layout. Also, did you install a hum pot? Pay attention to sources plugged in as well. Float the power cable - try reversing it - you may have to use a cheater plug. Getting hum in an amp project is VERY common. You have to go back and assess all of the above. It's a matter of trouble shooting to see where your problem lies. Sometimes tracking down that hum can be a horror, sometimes you'll stumble on it quickly. Sometimes, it's just blind luck. But it's luck you'll need. kh Quote Link to comment Share on other sites More sharing options...
NOSValves Posted October 31, 2002 Share Posted October 31, 2002 Actually with the right equipment finding a hum is really easy. A scope does wonders !! Of coarse most people don't have one to use and then the job can be hit and miss at best. Craig Quote Link to comment Share on other sites More sharing options...
No Disc Posted November 1, 2002 Share Posted November 1, 2002 Yes, hum in a amp is common, it seems to happen even to the best of engineers. Perhaps when I find my moondogs I will let these Wrights out of my clutches long enough for George to correct the hum. The hum is so very slight it's unoticeable unless the ear within inches of the Cornwall woofer. - tb Quote Link to comment Share on other sites More sharing options...
arco Posted November 1, 2002 Share Posted November 1, 2002 When you are done with all that and still have problems, you might also want to try Mr. Sakuma's solution: You use two earth points on the chassis, i.e. one to ground the AC (better through a 10 Ohm / 2W resistor) and power supply grounds and the other for the signal grounds. Quote Link to comment Share on other sites More sharing options...
DrPyro Posted November 1, 2002 Share Posted November 1, 2002 Craig, Okay....you have my interest! How would you track it down with a scope? I have one in my office, I don't think work would mind so teach away....... -dbl Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted November 1, 2002 Share Posted November 1, 2002 I recently saw a humless amplifier outside of Circuit City holding up a sign that said "needs wok" ...... but I think it was already fried. -c7s {kind of an SS joke.....} Quote Link to comment Share on other sites More sharing options...
chickey Posted November 1, 2002 Share Posted November 1, 2002 If you want to drive yourself really crazy and eliminate all potential sources of hum, then you need to think not only about electrically induced hum, but mechanical hum as well. Those big old toroid transformers in many amps can resonate and create hum independent of ground hum. Sometimes it's as simple as tightening down the mounts that fasten the transformer to the amp chassis. In other cases, the transfomer hum is bourne from AC offset noise, which can be combatted with things like the AH! AC Offset Killer. Quote Link to comment Share on other sites More sharing options...
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