as u guys see in the schematic I would like to powering the electret microphone
and connected to mic pre amps, and the mic pre amp has input impedance of 47 Kohm,
because the microphone has XLR connector, I connect the pin 2 in series with c1 before it goes to input of pre amp;
my question is if i put 6.8uF capacitor in series, would it be high pass filter? because the input impedance of mic pre amp (m040 pre amp) 47k, so the cut off frequency will be 0.5 Hz?
will it be ok? because the Frequency range of pre amp: approx. 10 Hz...100 kHz
do i have to use same value of capacitor for pin 3?
but it worked before, I put c1 and c2 6.8uF, the problem is when i connect it to the amplifier circuit and to the speaker and there is also noise there,
thats why i wonder if it is because the value of capacitor is not right?
but it worked before, I put c1 and c2 6.8uF, the problem is when i connect it to the amplifier circuit and to the speaker and there is also noise there,
thats why i wonder if it is because the value of capacitor is not right?
The capacitors won't introduce noise - but the resistors feeding the phantom power are also feeding the PSU noise directly in to the input of the amplifier. By using a proper impedance balanced amplifier this is cancelled out.
The capacitors won't introduce noise - but the resistors feeding the phantom power are also feeding the PSU noise directly in to the input of the amplifier. By using a proper impedance balanced amplifier this is cancelled out.
but the impedance from microphone is 300 ohms,
and the pre amp input impedance is about 47k ohms, so it is impedance bridging right?
so i think the impedance value is ok right?
but the impedance from microphone is 300 ohms,
and the pre amp input impedance is about 47k ohms, so it is impedance bridging right?
so i think the impedance value is ok right?
No, 47k is far too high - something like 4.7K or less would be usually for a low impedance mike input. But been phantom powered it's important that the preamp is balanced, otherwise you're just feeding noise to the input.
No, 47k is far too high - something like 4.7K or less would be usually for a low impedance mike input. But been phantom powered it's important that the preamp is balanced, otherwise you're just feeding noise to the input.
but in impedance bridging Z load >> Zsource right?
thats why i though the impedance of pre amp>> than mic impedance,
do u know how to feed the input from balance mic with phantom supply to unbalance pre amp ?
Partially, but mostly because you aren't using a balanced input - as I keep telling you. You're feeding power supply noise directly in the input of the amplifier.
Partially, but mostly because you aren't using a balanced input - as I keep telling you. You're feeding power supply noise directly in the input of the amplifier.
now i am using dynamic microphone, with Xlr connector also, and i would like to connect it to GSm modem. it has microphone + and microphone - connection, and i amplify the signal by connect the microphone to mic pre amp (kemo M040)
the connection like in the schematic..
but when i tried too call the modem, i can hear the voice from the mic, but also a lot of noise there
is there any suggestion to get rid of that noise?
because i tried connected directly o microphone input , and I could not hear anything,
I ever tested it with the microphone from handset and it works.
that s why i think it might be because of the signal from dynamic microphone is not loud enough
The Kemo preamp does not have a low impedance balanced input but it might work if the dynamic mic is connected with a short length of shielded audio cable.