RuudNL
Well-known member
For private use I have a Mackie 1402-VLZ. It works fine with all kinds of (phantom powered) microphones.
Recently, I plugged in a Behringer B-5 microphone.
(Yes, I know, mentioning the B*** word might sound like swearing, but their B-5 microphones are pretty good...)
To my surprise I heard a faint buzzing (100 Hz.) sound, that I never heard with other phantom powered microphones.
At the moment I switch the phantom power off and the capacitors are discharging, the microphone is still powered and the buzz is gone.
Voltage on pin 2 and 3 is 37.3 Volts during normal operation, so no excessive current consumption.
Other phantom powered microphones are completely clean. To exclude that there is something wrong with the B-5, I borrowed a C-2 from a friend and this microphone had the same problem: also a soft buzzing sound with phantom power on. So it seems it is a Behringer problem... (Could it be that the electronics do not provide a good symmetrical output, so that the common mode rejection suffers and the ripple on the phantom power voltage is amplified?)
This is the circuit diagram of the phantom power part of the 1402-VLZ:
Personally I think that the 100 uF is a bit small. Any thoughts about this problem?
Recently, I plugged in a Behringer B-5 microphone.
(Yes, I know, mentioning the B*** word might sound like swearing, but their B-5 microphones are pretty good...)
To my surprise I heard a faint buzzing (100 Hz.) sound, that I never heard with other phantom powered microphones.
At the moment I switch the phantom power off and the capacitors are discharging, the microphone is still powered and the buzz is gone.
Voltage on pin 2 and 3 is 37.3 Volts during normal operation, so no excessive current consumption.
Other phantom powered microphones are completely clean. To exclude that there is something wrong with the B-5, I borrowed a C-2 from a friend and this microphone had the same problem: also a soft buzzing sound with phantom power on. So it seems it is a Behringer problem... (Could it be that the electronics do not provide a good symmetrical output, so that the common mode rejection suffers and the ripple on the phantom power voltage is amplified?)
This is the circuit diagram of the phantom power part of the 1402-VLZ:
Personally I think that the 100 uF is a bit small. Any thoughts about this problem?