Reply to thread

Message

<blockquote data-quote="Mike Sokol" data-source="post: 58923" data-attributes="member: 1989">Re: How to Kill BuzzWith a little modification, this wouldn&#039;t be such a bad idea (but probably still illegal). Back in the 70&#039;s when I first started playing out in a rock band with a mixer in the back of the room, I had all sorts of ground loop hums from the rat-hole clubs we frequented. I knew that breaking off (or lifting) the ground pins on power cords was a bad idea, so I built a few similar boxes that included a pair of series/reversed 5 volt Zener diodes in the ground lines with a switch. That would allow the ground loop differentials between room outlets to be as much as 5.6 volts peak (approx 4 volts RMS) before they would begin conducting. Of course, if a piece of stage gear shorted internally to the line it would create a nice fault current and trip the breaker or blow the fuse. I used big beefy stud-mount Zener Diodes so they easily withstood the dead short currents without destroying themselves. Of course, there are better ways to do this now including audio isolation transformers and such, but those were the days I scrounged the city dump for old tube TV sets and radios to cannibalize for their output transformers often mounted right on the speaker frame. Worked pretty well, and the price was right. <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f642.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":)" title="Smile&nbsp; &nbsp; :)"&nbsp; data-smilie="1"data-shortname=":)" />~<img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f642.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":-)" title="Smile&nbsp; &nbsp; :-)"&nbsp; data-smilie="1"data-shortname=":-)" />~:smile:</blockquote>

[QUOTE="Mike Sokol, post: 58923, member: 1989"] Re: How to Kill Buzz With a little modification, this wouldn't be such a bad idea (but probably still illegal). Back in the 70's when I first started playing out in a rock band with a mixer in the back of the room, I had all sorts of ground loop hums from the rat-hole clubs we frequented. I knew that breaking off (or lifting) the ground pins on power cords was a bad idea, so I built a few similar boxes that included a pair of series/reversed 5 volt Zener diodes in the ground lines with a switch. That would allow the ground loop differentials between room outlets to be as much as 5.6 volts peak (approx 4 volts RMS) before they would begin conducting. Of course, if a piece of stage gear shorted internally to the line it would create a nice fault current and trip the breaker or blow the fuse. I used big beefy stud-mount Zener Diodes so they easily withstood the dead short currents without destroying themselves. Of course, there are better ways to do this now including audio isolation transformers and such, but those were the days I scrounged the city dump for old tube TV sets and radios to cannibalize for their output transformers often mounted right on the speaker frame. Worked pretty well, and the price was right. :)~:-)~:smile: [/QUOTE]

Verification