Melodeon.net Forums

Discussions => General Discussion => Topic started by: Saul Bailey on August 27, 2018, 12:00:42 AM

Title: PZM Phantom Mod
Post by: Saul Bailey on August 27, 2018, 12:00:42 AM
Ok, my little brain needs some help... I've got a Realistic pzm which I'm thinking of inserting into a box, Cutting-style. I know there are other threads about pzms but what I reeeally want to know is how the mic is powered after the snip.

Am I right in thinking that by just leaving the mic with a few inches and soldering on a jack socket, you cut out the battery box entirely? If this is the case then does one run a lead to a phantom power supply and that's that? Or are the batteries essential? I've seen Howard Jones' post about putting a jack onto the lead with the battery box, but it's not really for me...

Maybe this is a repeat of something, but the other threads started to get quite confusing! I'm really just looking for a sequence eg. mic --> jack socket --> jack to xlr ---> phantom supply and PA (or whatever's right...)

Hope someone with a bigger tech brain can help.
Saul :)
Title: Re: PZM Phantom Mod
Post by: Anahata on August 27, 2018, 08:40:47 AM
You need a few electronic components in there.
A minimal solution would have a pair of resistors to drop the voltage so the mic capsule doesn't see more than 12V (can be a little as 1V), and a capacitor to couple the mic output to pin 2 of the XLR.

More sophisticated versions supply a balanced feed to the XLR, or include capsule protection from a momentary high voltage when first plugged in.

Some examples here (https://electronics.stackexchange.com/questions/257819/phantom-power-supply-for-electret-mic). The 'updated circuit' looks a bit like what I had in mind, but it's for 12V phantom power and I'd have used much larger resistor values, and of course chosen resistor values to deliver a sensible mic supply voltage with 48V phantom power. Bear in mind that phantom power comes though a 6.8Kohm resistor, and that must be taken into account when calculating resistor values.

Google search for phantom power supply for electret mic (and similar) will find plenty of suggestions.

I could make you one...

PS better circuits here: http://www.epanorama.net/circuits/microphone_powering.html (scroll down past the Soundblaster rubbish)
SimplePortal 2.3.5 © 2008-2012, SimplePortal