Hi everyone
I am new to circuit design and I wanted to try to make a condenser microphone by starting with an existing circuit. I came across the Russell Technologies version of the Schoeps circuit.
http://russelltechnologies.co.uk/rt-sm01.html
Circuit: http://russelltechnologies.co.uk/images/rt-sm01.sch.pdf
Now, I already had a jli-2555bxz3-gp capsule and 2N4416 JFET lying around (because of that one YouTube video ofc). So I wanted to change the Schoeps circuit to fit the 2N4416 JFET.
Besides that, I wanted to add 2 LEDs to the circuit that turn on when phantom power is engaged. I wanted those LEDs to fade out quicker when phantom power is turned off.
See my circuit attached.
After simulating this circuit, I tried to make the circuit on a breadboard. The LEDs work, but still no signal from the capsule.
Can any of you see where my mistake is? And the more important question: why?
And here is the circuit with SPICE simulation. I changed a few things to make the SPICE simulation work:
1. Removed the ferrite bead;
2. Changed the capsule + and capsule - for a VSIN generator. (dc=1, ampl=7.94mV, f=1k, ac=1);
3. Removed XLR1 to GND, because not necessary for the simulation;
4. Changed XLR2 and XLR3 for VDC 48V generators.
In case you were wondering: The two LEDs are white LEDs.
Thanks a lot for the help!
- Ricardo
I am new to circuit design and I wanted to try to make a condenser microphone by starting with an existing circuit. I came across the Russell Technologies version of the Schoeps circuit.
http://russelltechnologies.co.uk/rt-sm01.html
Circuit: http://russelltechnologies.co.uk/images/rt-sm01.sch.pdf
Now, I already had a jli-2555bxz3-gp capsule and 2N4416 JFET lying around (because of that one YouTube video ofc). So I wanted to change the Schoeps circuit to fit the 2N4416 JFET.
Besides that, I wanted to add 2 LEDs to the circuit that turn on when phantom power is engaged. I wanted those LEDs to fade out quicker when phantom power is turned off.
See my circuit attached.
After simulating this circuit, I tried to make the circuit on a breadboard. The LEDs work, but still no signal from the capsule.
Can any of you see where my mistake is? And the more important question: why?
And here is the circuit with SPICE simulation. I changed a few things to make the SPICE simulation work:
1. Removed the ferrite bead;
2. Changed the capsule + and capsule - for a VSIN generator. (dc=1, ampl=7.94mV, f=1k, ac=1);
3. Removed XLR1 to GND, because not necessary for the simulation;
4. Changed XLR2 and XLR3 for VDC 48V generators.
In case you were wondering: The two LEDs are white LEDs.
Thanks a lot for the help!
- Ricardo
Your P48V phantom power supply is missing the 2 off 6k8 resistors that feed the 48V to the XLR. Without them, you will see zilch at the XLRs
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