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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Mike Sokol on July 02, 2014, 12:04:07 AM

Title: Guest Teachers
Post by: Mike Sokol on July 02, 2014, 12:04:07 AM
We'll play nice... we're learning, right?  We learn little if we kill the teacher.

Please let me know of any other manufacturers or persons you would like to invite for a guest discussion about a particular piece of technology that has to do with AC Power & Grounding. I do this sort of thing in my seminars and classrooms all the time, so why not do it in this forum?
Title: Re: Guest Teachers
Post by: David Sturzenbecher on July 02, 2014, 07:04:46 AM
Please let me know of any other manufacturers or persons you would like to invite for a guest discussion about a particular piece of technology that has to do with AC Power & Grounding. I do this sort of thing in my seminars and classrooms all the time, so why not do it in this forum?

The world will be a better place if more people hear the word of Bill Whitlock.
Title: Re: Guest Teachers
Post by: Mike Sokol on July 02, 2014, 08:46:15 AM
I'm thinking about calling this the "Led Talks" for Loud, Entertainment, Design as a play on "Ted Talks" which stands for Technology, Entertainment, Design. Plus I like the Led Zeppelin tie in.  ;D

The idea would be to announce in advance when this will happen and open the forum up to the guest lecturer for a period of 48 hours in the middle of the week (that's 2 days for us mathematically challenged). That should give all the forum readers around the world enough time to weigh in and ask questions, and the guest will know they only have to follow this thread for 2 days, not 2 years (or longer). After 48 hours we'll thank the guest and I'll lock the thread to stop further discussion.

What do you all think? Should we try to launch the Led Talks?   
Title: Re: Guest Teachers
Post by: Kevin Graf on July 02, 2014, 09:31:06 AM
While Bill Whitlock top's the list, others might include:

Jim Brown
then
Keith Armstrong (UK)
Mike Holt (blogs & videos)
Henry W. Ott
Title: Re: Guest Teachers
Post by: John Roberts {JR} on July 02, 2014, 10:15:15 AM
While Bill Whitlock top's the list, others might include:

Jim Brown
then
Keith Armstrong (UK)
Mike Holt (blogs & videos)
Henry W. Ott

Henry Ott and Ralph Morrison were two text book authors on the subject I read back in the '70s. Back then we would buy and read actual books...

JR
Title: Re: Guest Teachers
Post by: Tim McCulloch on July 02, 2014, 10:53:33 AM
Henry Ott and Ralph Morrison were two text book authors on the subject I read back in the '70s. Back then we would buy and read actual books...

JR

What are these "books" you speak of? /nudge, wink
Title: Re: Guest Teachers
Post by: John Roberts {JR} on July 02, 2014, 11:18:09 AM
What are these "books" you speak of? /nudge, wink
The OTT  book was "Noise reduction techniques in electronic systems", Morrison's was "Grounding and shielding techniques in Instrumentation" (note this was the second edition c.1977 so not a new area of study 35 years ago).

I am not suggesting that sound guys read these, I was designing actual products so more involved in such details.

Properly designed modern gear should just plug and play nice with others.

JR
Title: Re: Guest Teachers
Post by: Kevin Graf on July 02, 2014, 12:19:39 PM
For me the Ralph Morrison books were more of a challenge, because they were written in 'field' theory rather than 'circuit' theory. (Ott has a note on why he used 'circuit theory)
The Morrison books:
1986 Grounding and Shielding Techniques in Instrumentation.
1990 Grounding and Shielding in Facilities.
1992 Noise and Other Interfering Signals.   
Are now available used for $10 or $20.

**********************************
Henry W. Ott has a new (2009)and improved 850 page book:
Electromagnetic Compatibility Engineering
http://www.hottconsultants.com/book.html

Mr. Ott also does a few seminars each year.
Title: Re: Guest Teachers
Post by: Mike Sokol on July 02, 2014, 01:55:17 PM
Remember, we're looking for guests that can speak on AC Power & Grounding topics. For instance, I think it would be great to have a SurgeX engineer do one about their products (don't have a name). Maybe a generator manufacturer could speak about grounding/bonding issues. I know we could get someone from Whirlwind to talk about their new power distro gear. I've been on Mike Holt's forums a bunch, and grounding/bonding issues are one of his soapbox subject, so I might be able to entice him here for a Led Talk.

These topics can include noise issues as well. So things like audio transformers, Star-Quad cable, and technical grounds are fair game. Hey, I would take a guitar pickup builder to discuss exactly how humbucking pickups work. How about any DI builders, especially about active DI's with phantom isolation.
Title: Re: Guest Teachers
Post by: Frank DeWitt on July 02, 2014, 03:49:19 PM
I am a DI builder, but passive only.  I can comment on types of jacks, what to ground to what, Faraday shields,  aluminum vs steel case ETC.

I believe Ray Rayburn did some research on active DIs. As you hinted, the problem is how to supply phantom power and still not have a ground loop. The cheep way is to cheat and get the phantom power through a resistor and hope that is isolation enough.  It isn't.  The right way is what Radial does.  You run a switching powersuply with the phantom power run the AC from the switching powersupply through a transformer to gain isolation. rectify the AC and run the active DI circuit.

NICE, and it works, and it is expensive.

Frank 
Title: Re: Guest Teachers
Post by: Jonathan Johnson on July 02, 2014, 05:12:54 PM
The idea would be to announce in advance when this will happen and open the forum up to the guest lecturer for a period of 48 hours in the middle of the week (that's 2 days for us mathematically challenged). That should give all the forum readers around the world enough time to weigh in and ask questions, and the guest will know they only have to follow this thread for 2 days, not 2 years (or longer). After 48 hours we'll thank the guest and I'll lock the thread to stop further discussion.

Regarding format -- occasionally, Slashdot (http://slashdot.org/) (one of the original crowd-sourced news aggregators) will feature an interview where the crowd can ask questions. The way they do it is they create a new post inviting questions for the interviewee. Sometimes it's on a specific subject, sometimes the floor is open to anything. After a couple of days, the most upvoted questions are passed on to the interviewee; a week or so later the interviewee's responses are posted as a new article.

Maybe you could adapt that approach. Of course, we don't have an "up/down-vote" process here, but that would be a way of minimizing the amount of time the guest would have to spend here. Then if they wanted to, they could respond to followup questions.
Title: Re: Guest Teachers
Post by: John Roberts {JR} on July 02, 2014, 05:41:35 PM
I wouldn't over think this, or make it harder than need be. If you find some authoritative professional willing to participate invite him to join and start a thread asking for questions. This will make it easier for people who work odd hours to participate, and it gives him or her the luxury of taking their time to answer thoughtfully.

JR
Title: Re: Guest Teachers
Post by: Mike Sokol on July 02, 2014, 05:52:02 PM
I wouldn't over think this, or make it harder than need be. If you find some authoritative professional willing to participate invite him to join and start a thread asking for questions. This will make it easier for people who work odd hours to participate, and it gives him or her the luxury of taking their time to answer thoughtfully.

JR

That's what I'm thinking. I just want to limit this to perhaps 48 or 72 hours so the guests don't feel they need to be active on the thread forever. We could announce who the guest is along with the starting day and time the week before. When it's time to roll I'll start the thread, the guest could make an introduction if they like, and you guys pose some questions. He'll probably pose some questions back to you guys since this is a two way street. Don't expect an immediate answer just like any other thread, so they could get back to a question an hour or a day later. After the allotted time I'll do a thank-you and lock the thread.

I think if we keep it simple and everyone behaves themselves, we're gonna learn some really interesting stuff.
Title: Re: Guest Teachers
Post by: frank kayser on July 02, 2014, 06:56:47 PM
On the right track IMO.  Carry on.
frank