renx
Well-known member
Hello everyone,
I got this beautiful neumann um57 mic without a psu. I built my own according to the following specs:
um57:
pin1 = GND
pin2 = signal +
pin3 = anode voltage = +160v
pin4 = heater= +5.8v
pin5 = signal -
pin6 = pattern (from 0v to 160v)
I used Gyrafs g7 psu schematic almost entirely except for the lm317t resistor (I needed 5.8v instead of 6.3v). I also connected ...
now, everything works fine except when I put the pattern switch on cardiod (+80v) I get hum-noise.
I put a 1000uF capacitor in parallel with the bottom 100k resistor and it killed the noise totally, but when I switch between the patterns sparks fly out of the switch and eventually it stops working!
Any ideas would be very helpful.
Regards!
I got this beautiful neumann um57 mic without a psu. I built my own according to the following specs:
um57:
pin1 = GND
pin2 = signal +
pin3 = anode voltage = +160v
pin4 = heater= +5.8v
pin5 = signal -
pin6 = pattern (from 0v to 160v)
I used Gyrafs g7 psu schematic almost entirely except for the lm317t resistor (I needed 5.8v instead of 6.3v). I also connected ...
now, everything works fine except when I put the pattern switch on cardiod (+80v) I get hum-noise.
I put a 1000uF capacitor in parallel with the bottom 100k resistor and it killed the noise totally, but when I switch between the patterns sparks fly out of the switch and eventually it stops working!
Any ideas would be very helpful.
Regards!