Phantom power blocker

[swpaskett]

I knew somebody would jump on the misuse of the term "gain." It was a mistake, I confess, and it only confused the issue more. There is a good writeup on magamps here: Magnetic amplifier - Wikipedia if anyone cares to do some reading. A few years ago there was still one company producing audio amplifiers based on the magamp principle. I doubt they are still around; they wanted a lot of money for a piece of retrotech that is hard to linearize.

 

[abbey road d enfer]

I knew somebody would jump on the misuse of the term "gain." It was a mistake, I confess,

My comment was not about criticizing the use of "gain", but to alert that in the specific circumstances, whatever gain variation there was was not the dominant effect.
Magnetic amps have been made obsolete by the availability of high-power IGBT's.

 

[gyraf]

..on a side note, small-scale/low-current magnetic amps are still great fun and do stuff that our ears often agrees with. Like the Ortofon STL631 de-esser - one of my favorite examples of this..

 

[Grim Reaper]

https://content.instructables.com/p...ower-Blocker-protect-Your-Dynamic-Microph.pdf

 

[gyraf]

naa, that one does not really do what it claims

 

[Grim Reaper]

naa, that one does not really do what it claims

Explain please.

 

[gyraf]

..in the first place, phantom won't ever, in any way, interfere with your correctly wired dynamic mic. This only happens with damaged or wrong wireing. Which this circuit does not protect you from - the 100uF capacitors store plenty energy to damage hair-fine moving coils - and if they were smaller-to-safety, it would severely limit low frequency response. There is no "free lunch" here, or we would off course already have implemented this.. or rather, there's in reality no problem to fix here: It's an imagined problem.

In our SSL room, we switched on phantom power when we built the room in 1987 or so, and didn't switch it off until 2009 when we decommissioned the desk. Yes, the phantom switch was in the basement, on the back of the huge power supply rack.

I did not log a single dynamic/ribbon mic malfunction from studio2 over these years...

/Jakob E.

 

[abbey road d enfer]

..in the first place, phantom won't ever, in any way, interfere with your correctly wired dynamic mic. This only happens with damaged or wrong wireing. Which this circuit does not protect you from - the 100uF capacitors store plenty energy to damage hair-fine moving coils - and if they were smaller-to-safety, it would severely limit low frequency response.

I believe this circuit protects all that is east of it. E.G. if it is connected east-side to a patchbay, any mic is safe even in case of short, open or crossed circuit, because it simply inhibits phantom.
I agree that a short on one of the hot pins of the west connector results in potential danger.

It's an imagined problem.

Regarding dynamic mics, yes.

I did not log a single dynamic/ribbon mic malfunction from studio2 over these years...

Do you have mics on patchbays?