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Author Topic: EEVblog #616 - How Microphone Phantom Powering Works  (Read 11409 times)

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Offline EEVblog

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EEVblog #616 - How Microphone Phantom Powering Works
« on: May 15, 2014, 01:49:11 PM »
Doug Ford, former head designer at Rode Microphones explains 48V phantom powering of microphones and how it works.
There is a ton of stuff here:
Electrostatic and electromagnetic noise, differential amplifiers, common mode noise, transformer magnetisation current, JFET differential driver circuits, balanced impedances, phase splitters, miller capacitance and how it matters, and he explains how the Schoeps amplifier topology works.

 

Online Richard Crowley

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #1 on: May 15, 2014, 02:21:44 PM »
As Mr. Ford alludes to in this video, modern, high-end transformer-makers discourage putting ANY DC current through their devices, even purportedly "balanced" current using a center-tap.  They recommend using the same topology used in transformerless designs, the matched 6K8 resistors and even better with DC blocking capacitors to protect the transformer.
 

Offline rdl

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #2 on: May 15, 2014, 02:34:19 PM »
Seriously? Another microphone video? Yes, they're interesting but are you actually trying to lose audience? I had breathed a sigh of relief when the Prema multimeter and Cebit videos appeared, but I guess that was premature.
 

Online Richard Crowley

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #3 on: May 15, 2014, 02:49:21 PM »
Perhaps Mr. Jones' audience is wider than just test-gear geeks.  I'm sure I'm not the only recently-new member who was attracted by the microphone series.

I hope Dave can arrange a similar series of interviews with another innovative Australian company, Blackmagic Design.
 

Offline david77

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #4 on: May 15, 2014, 03:19:06 PM »
As my main interest lies in audio electronics I find these videos with Mr Ford very interesting, looking forward to the next installment  :-+.

How about getting in touch with Rod Elliott?
 

Offline Monkeh

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #5 on: May 15, 2014, 03:45:09 PM »
Seriously? Another microphone video? Yes, they're interesting but are you actually trying to lose audience? I had breathed a sigh of relief when the Prema multimeter and Cebit videos appeared, but I guess that was premature.

Afraid of learning something on Youtube?
 

Online Richard Crowley

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #6 on: May 15, 2014, 04:07:12 PM »
How about getting in touch with Rod Elliott?
Yes! I would like to see that also!
 

Offline EEVblog

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #7 on: May 15, 2014, 04:22:27 PM »
How about getting in touch with Rod Elliott?

I know Rod, so that's possible.
 

Offline EEVblog

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #8 on: May 15, 2014, 04:23:30 PM »
I hope Dave can arrange a similar series of interviews with another innovative Australian company, Blackmagic Design.

I've asked around about that, and I hear they are super-duper secretive, so was told not to even ask!
 

Offline EEVblog

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #9 on: May 15, 2014, 04:25:22 PM »
Seriously? Another microphone video? Yes, they're interesting but are you actually trying to lose audience?

You are welcome to unsubscribe at any time, or simply not watch them. As always, it is very clear from the title what the video is.
Would you have complained if I didn't upload anything at all today?
I got several hours of footage with Doug, so I'm breaking that up into useful chunks.
 

Offline Monkeh

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #10 on: May 15, 2014, 04:26:25 PM »
I got several hours of footage with Doug, so I'm breaking that up into useful chunks.

And most of us are enjoying it immensely and learning things. Keep it up!
 

Offline Lightages

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #11 on: May 15, 2014, 04:47:47 PM »
Let me see..... I get to watch a short video of someone who knows what they are talking about so I can learn something for free and even ask questions and maybe get them answered. I have a choice if I want to watch. I am so pissed off...... ::)
I am NOT a distributor for Brymen.
 

Offline nitro2k01

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #12 on: May 15, 2014, 04:51:30 PM »
I for one find the microphone videos interesting. Keep'em coming, lads.
Whoa! How the hell did Dave know that Bob is my uncle? Amazing!
 

Offline azi

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #13 on: May 15, 2014, 05:19:35 PM »
Seriously? Another microphone video?

Dave has said many times that he can't please everyone.

Audio electronics is a special field that does not interest everyone, but the people who are interested are often fanatical.
 

Offline EEVblog

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #14 on: May 15, 2014, 05:49:40 PM »
Dave has said many times that he can't please everyone.
Audio electronics is a special field that does not interest everyone, but the people who are interested are often fanatical.

The number of views on the microphone videos has been about half the usual, and that's to be expected.
I for one think this video has lots of circuit detail that can apply to more than just mics, so it's certainly bang on topic. Some other like the microphone patterns etc have been admittedly less so.
 

Online G7PSK

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #15 on: May 15, 2014, 06:09:05 PM »
I for one find the microphone and its construction and use very interesting. When the information is put over in such an entertaining manner by someone like Doug Ford it make learning so much easier.
Microphones and audio is used in some form the majority of electronics that most people come into contact with so to my mind its a very important subject.
Doug and Dave get a big  :-+ from me for this series.
 

Offline jancumps

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #16 on: May 15, 2014, 06:29:11 PM »
I learned a few things today.

And it ends with a cliffhanger  :).
 

Offline DrGeoff

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #17 on: May 15, 2014, 08:02:17 PM »
It's been a good series of videos on mics and, as you've noted, some circuit topologies and techniques that can be used outside the audio industry.
Big thanks to Doug for spending the time to do this.
« Last Edit: May 15, 2014, 09:05:45 PM by DrGeoff »
Was it really supposed to do that?
 

Offline delmadord

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #18 on: May 15, 2014, 08:57:56 PM »
I must say I really like the microphone series too, even thou I do not make anything with them. There are a lot of other physics/electrical/electronics stuff explained by Doug that are really helpful/interesting to me. I think that it would be a shame to stop making videos like this.
 

Offline Tuoppi

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #19 on: May 15, 2014, 09:12:26 PM »
I for one think this video has lots of circuit detail that can apply to more than just mics, so it's certainly bang on topic. Some other like the microphone patterns etc have been admittedly less so.

This. For me as a beginner, there are a lot of things to learn about general electronics from these discussions. And the most important of all, is observing the train of thought of people who actually know about the topic and have worked on that for a living for a long time.

And then, well, this is free. Even if the video would be 30 minutes of Dave and Doug dancing a waltz together it would still be a good run for your money (and still better than 50% of the content you can see on Youtube.... ok, 30%). Watching this, or any other video, is not compulsory.
 

Offline madires

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #20 on: May 15, 2014, 09:49:36 PM »
I like the microphone 101 mini series, it's interesting and it gives a good insight into the technology which wouldn't fit into a single video of 20 minutes. It's a nice idea to have a mini series about a specific topic from time to time, especially if Dave can get another EE in front of the camera.
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Offline 13hm13

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #21 on: May 15, 2014, 09:54:54 PM »
Most of Dave's videos "auto-captivate" ... I get drawn in and interested ... not feeling any urge to click away ... that said ...and despite having a great interest in audio (that's what got me hooked to EE decades ago) ... well,  these microphone vids just don't have the usual EEV sparkle. 
But, hey ... that's just one person's 0.02 worth ;)
« Last Edit: May 15, 2014, 11:06:09 PM by 13hm13 »
 

Offline Rigby

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #22 on: May 15, 2014, 11:44:33 PM »
Most of Dave's videos "auto-captivate" ... I get drawn in and interested ... not feeling any urge to click away ... that said ...and despite having a great interest in audio (that's what got me hooked to EE decades ago) ... well,  these microphone vids just don't have the usual EEV sparkle. 
But, hey ... that's just one person's 0.02 worth ;)

Yeah, same.  Doug Ford is definitely a neat dude, and ridiculously intelligent but I'm Dougged out for a while.  I'll come back and watch these microphone vids later.
 

Offline rdl

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #23 on: May 16, 2014, 12:31:11 AM »
I just thought that 42% of EEVblog videos about microphones was a bit too much. If 6 of the last 14 videos had been about that little electric vehicle I bet you guys would be up in arms.

 :)
 

Online Richard Crowley

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Re: EEVblog #616 - How Microphone Phantom Powering Works
« Reply #24 on: May 16, 2014, 12:57:09 AM »
I just thought that 42% of EEVblog videos about microphones was a bit too much. If 6 of the last 14 videos had been about that little electric vehicle I bet you guys would be up in arms.
That's pretty selective statistical analysis.  I could say the same thing about test equipment.  I would bet that most of us are less enamored by analysis of test gear and consider it just a utilitarian tool like a screwdriver.  And what's the obsession with soldering irons?  As a newcomer here, I perceive that this community really has its fetishes. I strongly suspect that after Dave is finished doling out the episodes from Mr. Ford, we will likely never hear of microphones again.  But I will still regularly slog through DMMs and soldering irons until the end of time.  At least the mailbag brings some variety.
 


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