
Thanks both of you for your help! -Casey
Oops, I've already ordered some regular LEDs... "minimum operating current" specs not available... I'll see how those work at least in terms of detecting standard phantom and simple miswirings... It's surprising to me (just on an intuitive level) that raw phantom power wouldn't be able to light up any little LED...So you might look for "high efficency" LEDs, that will light with ~5 mA.
And the idea there is to use them while operating whatever is going to be plugged in? These protect the box? Is this basically what a passive DI is?Also, transformer isolation is probably the best solution
The thing that occurred to me is that with any sort of detector, it only gets you halfway there. You can tell that there are wiring problems, but you don't have any way to fix them. For phantom power, it is probably simple enough to turn it off (unless it's globally switched, and something else requires it)...but for AC power and ground problems, they aren't always easy to fix with the tools at hand.And the idea there is to use them while operating whatever is going to be plugged in? These protect the box? Is this basically what a passive DI is?
Maybe I'll just start with the LEDs unless the transformer thing is a really simple proposition.
True. The way I'm going to build it it's not even going to do a particularly good job of telling me what's wrong, just that "something is wrong". And although it only detects, at least can stop me before I fry me or my precious box.From the sounds of this, you'll be using it in the heat of battle, while setting up to play, when the last thing you really need to be thinking about is how the power and sound are wired.
So I guess the real answer is for me to suck it up and get a nice stereo DI. Meantime I'll build the detector for fun. Total expected cost for the detector parts w/shipping: $7. Thanks to the helpful folks on tapeop.com, of course.Isolating your rig from the sound system using transformers means you don't have to worry if there's phantom or not.
That's one of the brilliant things about phantom power: the current limiting resistors also make it very tolerant of various mispluggings. You can short any combination of the lines to each other, and at worst you're drawing 15 mA from the phantom supply.And: Off the top of your heads, is there any way that mis-wiring or short-circuiting on MY part could fry the various things I'll be testing with it? (That would be a tad ironic, eh?) That only occurred to me as I was soldering it together and realizing how crammed everything was inside the XLR jack.
Nothing wrong with that...it's only wire after all...as long at the 1/4" cable isn't broken.I'm not sure if the average lengths of a 1/4" cable would make them inappropriate for this use for some reason. Thoughts?
Yeah, but you'd need a flashlight to find a loose mic cable onstage. Chicken and egg, my friend, chicken and egg.The Scum wrote:Looks good.
Come to think of it, you could take a handful of how-current white LEDs, and XLR, maybe a switch and piece of copper pipe, and wire them up so they you had a phantom-powered flashlight!
I've done live sound gigs where that would have been pretty handy!
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