Make my own phantom power (and also CAD 4 mic set)?

[Deege]

My dad is an electrician (has fixed TVs for about 20 years or more...really good at it too), and I am wondering if there are any sort of diagrams or anything out there to make my own preamp. I am ordering the CAD 4 piece drum mic set (if it's any good, anyone know?), and it comes with one condensor mic, which I plan to use as an overhead. I originally planned to get 2 condensor overheads but I stumbled upon this kit, and the frequency response on the bass drum mic has more low and high end than an AT Pro 25, which I originally planned to get...
but anyway, my dad could order certain parts etc and make me a box for phantom power pretty easily if we had a schematic of some sort. My dad doesn't know anything about phantom power though, but if there was a website I could read about it, he could do it...
anyone have any advice about the CAD mic set or the phantom power issue?

 

[sjjohnston]

Do you want a preamp or just a phantom power unit?

There are schematics for various preamps scattered around here and there. Opamp Labs, for example. There are kits available, from Paia, among others. Some manufacturers (Rane, I think) post schematics of their products on their websites, so you can copy them.

If you just want phantom power, that's pretty simple. Connect 48V to the hot and cold signal lines, each with a 6.8 kohm resistor. The resistors must match (though they can be off the nominal value by ordinary tolerances).

 

[Deege]

Do you want a preamp or just a phantom power unit?

There are schematics for various preamps scattered around here and there. Opamp Labs, for example. There are kits available, from Paia, among others. Some manufacturers (Rane, I think) post schematics of their products on their websites, so you can copy them.

If you just want phantom power, that's pretty simple. Connect 48V to the hot and cold signal lines, each with a 6.8 kohm resistor. The resistors must match (though they can be off the nominal value by ordinary tolerances).

hmmm I dunno. I'm gonna build a little box with 2 ins and outs, for 2 drum overheads....but for now I will just have one condensor overhead for awhile until I can afford some better overheads. What do you recommend? Will I need a preamp or will phantom power alone suffice? My soundcard has +4 to -10db preamp in each channel....it picks stuff up enough really...but I know nothing about condensors...

 

[sjjohnston]

As to the preamp: the basic function is a microphone preamp is to amplify a mic-level signal up to line level.

A condensor mic, if anything, typically has a hotter output than a dynamic mic, because the mic body has a small amplifier in it which amplifies the really tiny signal from the capsule. So ... as long as you give it phantom power (assuming it needs it -- electret condensors often can run off of batteries), it doesn't need a preamp any more (or less) than a dynamic mic.

On the other hand, a good condensor mic will tend to have more detail in the high end than a dynamic mic (though, of course, various mics are different). It's possible you might feel the need for a better preamp more fully to exploit the advantages of a condensor v. a dynamic mic. Maybe. Maybe not.

Back on the first hand, condensor mics tend to be less sensitive to loading issues than dynamic mics. As some have noted, the sound of a dynamic mic may vary quite a bit depending on the mic preamp it's run into. This seems to be a common observation about the Shure SM57.