I made a capsule microphone amplifier according to the circuit diagram circulated on the network
Working with 48V phantom power supply
But when I finish, it won't work properly?? The microphone has no sound
I don't know if there is something wrong with the circuit diagram. Please help me
Thank you.
Working with 48V phantom power supply
But when I finish, it won't work properly?? The microphone has no sound
I don't know if there is something wrong with the circuit diagram. Please help me
Thank you.
Attachments
Looks like it is designed for a condenser microphone capsule without built-in JFET. Most electret capsules have a built-in JFET and won't work.
You could cut out the first stage, though: remove J1, connect the capsule with FET between R3 and ground, swap XLR pins 2 and 3 and take for granted that the output is driven single-endedly.
You could cut out the first stage, though: remove J1, connect the capsule with FET between R3 and ground, swap XLR pins 2 and 3 and take for granted that the output is driven single-endedly.
Common $2 electret microphones are designed to work with much lower voltage, as low as few volts. Will likely burn at 48 volts.
Agree they won´t burn, but they will not work either.
The circuit shown is for a real condenser capsule, not an electret, and is meant to be within an inch of so away, if that far, obviously inside the microphone head enclosure.
I guess the OP found the schematic, designed and built a PCB, which is too large to fit inside the Condenser head .... it won´t work that way (horrible hum buzz antenna) and as mentioned , won´t work with an Electret, unless modded.
I suggest replacing the 1 Gigaohm biasing resistor by the string : +48V > 47k > 4k7 > 2 pin Electret Capsule > ground
with a 9V zener in parallel with a 100uF capacitor going from 47k-4k7 node to ground.
The rest of the circuit can work as-is but I would aso replace R2 by 220k, now no need for 1 Gig resistors; of so also replace C1 by .1 to .47uF
NOW you can put the electret capsule a reasonable distance from preamp, still using shielded wire.
The circuit shown is for a real condenser capsule, not an electret, and is meant to be within an inch of so away, if that far, obviously inside the microphone head enclosure.
I guess the OP found the schematic, designed and built a PCB, which is too large to fit inside the Condenser head .... it won´t work that way (horrible hum buzz antenna) and as mentioned , won´t work with an Electret, unless modded.
I suggest replacing the 1 Gigaohm biasing resistor by the string : +48V > 47k > 4k7 > 2 pin Electret Capsule > ground
with a 9V zener in parallel with a 100uF capacitor going from 47k-4k7 node to ground.
The rest of the circuit can work as-is but I would aso replace R2 by 220k, now no need for 1 Gig resistors; of so also replace C1 by .1 to .47uF
NOW you can put the electret capsule a reasonable distance from preamp, still using shielded wire.
Yes, I think you are right, but I can't understand the connection mode you said. Can you give me a circuit diagram. If you can! Thank you.
Indeed, I wrote the same in post #3 and PRR in post #2.
Maybe I'm just being paranoid, but I wonder what impact Zener (or rather avalanche) diode noise will have. The differential resistance of a 9.1 V Zener (avalanche) diode is not very large (40 ohm typical for a Nexperia BZX79-C9V1 biased at 1 mA, https://nl.mouser.com/datasheet/2/916/BZX79-1320091.pdf ), so the electrolytic capacitor in parallel will not filter its noise very well, and the PSRR of an electret capsule with built-in JFET common source stage is practically 0 dB.
The same holds for the original circuit, by the way. There is a 330 ohm resistor between Zeners and filter capacitors, but the filter capacitors are much smaller.
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Feel free to use the voltage regulator you please, I am showing the principle on which an Electret Capsule can be used there.
But my verbal description is EEEAAASSSYYYYY, others understood well enough to criticize my idea, go figure.
Maybe some good Samaritan could draw it for you.
Or you do it yourself, really.
Pencil and paper, no need for more.
Tell that to marcelvdg who wrote that again in post #6, directly above my answer, and to which I was replying.
Oh ... wait ....
Sorry , too busy to fire up some drawing software and do it for you.
But my verbal description is EEEAAASSSYYYYY, others understood well enough to criticize my idea, go figure.
Maybe some good Samaritan could draw it for you.
Or you do it yourself, really.
Pencil and paper, no need for more.
Tell that to marcelvdg who wrote that again in post #6, directly above my answer, and to which I was replying.
Oh ... wait ....
Yes, I made a PCB according to the circuit diagram. It's a pity, but it can't work well
OK, thank you for your reply. My English level is too bad, so I can't understand your description from the text. I'm really sorry!! This is my own reason
I like this better, but please use 10k for R1, the proper value for 9V and thereabouts; classic 2k2 is for 1.5V to 3V supplies (single/double AAA battery or Sound Blaster supply or button cell) ; for 5V supplies already 4k7 is advisable.
First time you even mention your 34mm capsule 😉
Can you add more data about it?
At least a datasheet.
IF available, an Application Note would be a nice complement, or a circuit example where it´s actually used.
EDIT:
Well, that doesn´t tell us much, does it?
😉 😉