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Gear / Technical Help => Ask The Tapers => Topic started by: mcnys on January 23, 2012, 11:05:32 AM
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hello all,
very embarrassing question...so here i go :) today i was thinking, if its possible to use mic capsules without they'r preamp, and use my own...for example why i cant run AKG Acoustics CK 62-ULS capsule without c480b preamp(and just use my recorders preamp)? maybe there are some cables that that i don't know about?
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A while ago someone not connected to AKG made such a setup for a while; the jklabs boxes did such a thing. They used special connectors, cables, and powering boxes. Unfortunately the maker disappeared and as such there are only a handful of boxes still out there and working.
Recently, Jon at Naiant Studios, started work on a capsule-only system for a variety of mic families (beyer, schoeps, akg, etc). Some of those are out and about now (mic setups that already can run with the bodies separate from the caps), and some are still in development. For AKG specifically, I recommend checking out the Team thread in that section of the forum.
Either way you'll still need something between the cap and recorder to properly create the polarization and power voltages that the cap uses from the 48v phantom power that the recorder provides.
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ohh thank you very much for your informative answer ;)
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mcnys, there really are two very different kinds of "preamp" involved here. Or actually, in professional audio, the part of a condenser microphone that its capsule goes directly onto (a/k/a the "body" of the mike) is usually called an amplifier rather than a preamp. But then things get really strange semantically after that; you plug a cable into the "amplifier" of a microphone and you connect the other end of that cable to ... a preamplifier. Since when does the "pre" thing go after the thing that's not "pre"? Well, for better or worse that's the usual terminology in audio.
Anyway, a capsule is basically just a high-quality air capacitor in an insulated housing. Classic condenser microphone capsules need a polarizing voltage (DC typically at around 60 Volts) to make them able to turn sound energy into a varying signal voltage. But a capsule alone can't put out any electical current to speak of, and that's a part of what's needed for a signal to travel down a wire. So the "amplifier" part of a microphone gives the capsule its polarizing voltage and converts its varying signal voltage from being nearly "currentless" (= ultra-high impedance) to a low enough impedance that at least a little bit of current will get pushed down the cable. Again, that's the microphone's own built-in amplifier, not a preamp.
The amplifiers of professional microphones also convert their capsules' signals from unbalanced to balanced. That's not needed if you're going to connect the microphone to the unbalanced inputs of consumer recorders, but all professional and most "semi-professional" microphones have balanced outputs anyway, and then you have to unbalance their signals somehow. So it's understandable that people would look for ways to cut costs and keep the signals unbalanced all the way from the capsules to the recorder inputs, although that approach brings limitations of cable length and vulnerability to interference.
--best regards
P.S.: I don't find the question stupid at all.
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DSatz has put it very well.
I have often heard the amplifier in the microphone body called a "Line Driver" to avoid the "amplifier" confusion.
And, no, I don't think it's a stupid question either. You have to ask questions to learn. Good on you for asking.