Yes, and the noise is lower if the signal is amplified right at the transducer, instead of sending the signal
down the cable first.
down the cable first.
Not necessarily. I've seen one (AKG) that was just a cathode follower. It is mostly there to provide a lower output impedance. Capacitor microphones have enormous output impedance, which makes any length of cable to the next active stage too long. So they put it in with the microphone.
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Hi,
Well more or less.. yes but it depends on what you call 'amplify': a voltage amplification? A current amplification?
If you think about the 'classic' ( u47,67,...) circuits most of them are common grounded amplifier ( with or without global feedback, most of the time with local feedback/ degeneration) so they give a bit of voltage gain, often downsized by the circuit output transformer. Sony C37, C800, C12a ( Akg) are cathode follower circuits so they don't give any voltage gain but current gain: the voltage of caspule is what you get as output level ( more or less, a transformer in step up could give some gain though).
Other circuits merging both are or have been used too ( Groove Tube microphone often used both a common ground and a cathode follower, most chinese mics are based around a CCDA circuit, ...)
http://www.foxaudioresearch.ca/CCDA.htm
Rather than seeing the 'amplifying' of things both circuits share a common goal: change the impedance of the capsule ( very high) to a compatible one to drive lines to the preamp... which will take the voltage amplification to adapt to next circuit's needs ( console, eq, comp, ad,..).
Well more or less.. yes but it depends on what you call 'amplify': a voltage amplification? A current amplification?
If you think about the 'classic' ( u47,67,...) circuits most of them are common grounded amplifier ( with or without global feedback, most of the time with local feedback/ degeneration) so they give a bit of voltage gain, often downsized by the circuit output transformer. Sony C37, C800, C12a ( Akg) are cathode follower circuits so they don't give any voltage gain but current gain: the voltage of caspule is what you get as output level ( more or less, a transformer in step up could give some gain though).
Other circuits merging both are or have been used too ( Groove Tube microphone often used both a common ground and a cathode follower, most chinese mics are based around a CCDA circuit, ...)
http://www.foxaudioresearch.ca/CCDA.htm
Rather than seeing the 'amplifying' of things both circuits share a common goal: change the impedance of the capsule ( very high) to a compatible one to drive lines to the preamp... which will take the voltage amplification to adapt to next circuit's needs ( console, eq, comp, ad,..).
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Ejp: it looked like an older C414 ( silverish)? C12a. I liked the one we had in studio, great for ambience/distant mic for cabinets.
I like cathode follower mics. If the capsule allow you can really close mic with these circuits ( you might even have to use a pad on percussive instruments!).
The real downside is the need for high gain preamp if you plan room/ambience use. Nothing more problematic than some ribbons mics though. But it can be deceiptive for users: they are usually clean sounding ( depends on out transformer imo) and as they have low output people underate their potential imo.
I like cathode follower mics. If the capsule allow you can really close mic with these circuits ( you might even have to use a pad on percussive instruments!).
The real downside is the need for high gain preamp if you plan room/ambience use. Nothing more problematic than some ribbons mics though. But it can be deceiptive for users: they are usually clean sounding ( depends on out transformer imo) and as they have low output people underate their potential imo.
Krivium: I had three C60s in for service. I rebuilt the PSUs. This unit was also sold by Phillips as 6154.
If it is electret condenser microphone, yes, there is most likely fet transistor, often right there inside the capsule.