Yes, the output from a microphone is at an extremely low level, the AV inputs are at line level - you need a high gain microphone preamp.whatthe said:i need to plug a tie clip microphone into a tv's AV inputs (audio obviously). When i plug it in there is no sound at all. I'm guessing i need a preamp, is this correct ?
50mV in and 1V out is only a gain of 20 times, and 2 to 200mV is only a gain of 100 times - this looks far too low for a microphone preamp. I'm also confused why it gives different gain figures like that?.whatthe said:ok. i bought a preamp today from jaycar i have wired it all up but it's not working. when i use a 12vdc power supply it hums like crazy and if you tap the mic really hard you can hear the thump. i am using shielded cable. i thought the power supply might be causing interference so i then used a 9v battery and then there was no hum but if i hit the mic extremely hard i could here a faint thump. whats wrong ? below are amp specs and diagram of what i have done.
kemo m040 preamp
Operating voltage: 9...24 VDC
Frequency response: 10 Hz ... 100 kHz
Input: 2 - 50 mV
Output: 200 mV 1 V
Dimensions: 30 x 25 x 15 mm