Powering a 2-pole 3.5mm (1/8") connected electret microphone with a Xenyx 302USB
There is a 3,5mm (1.8") microphone jack at the top right of the Xenyx 302USB.
It seems to be wired the same as in SoundBlaster sound cards, and have a 4V voltage for driving electret condenser microphones:
/ \ | | Tip - Audio signal \ / +===+ | | Ring - Bias voltage for microphone (+4V) |===| | | | | Sleeve - Ground | | +=======+ | |
Schematics adapted from: Powering microphones
However my electret microphone seems to be wired like this:
/ \ | | Tip - Audio and bias voltage (+3V) \ / +===+ | | | | | | | | Sleeve - Ground | | +=======+ | |
I think it runs on 3V so 4V is close enough I guess.
So I am using a wiring block to make the ground not extend to the ring, and have the signal + voltage on both the ring and the tip, going into the mixer:
/ \ | | Tip - Audio and bias voltage (+4V) \ / +===+ | | Ring - Audio and bias voltage (+4V) |===| | | | | Sleeve - Ground | | +=======+ | |
Source quote for the voltage:
The 302USB does not have the higher voltage phantom power used in older mixers. It does have the 14 volt on the XLR and the 4 volt on the 1/8' (3.5 ) bias for electert mics. This is not something you can turn off but is not a problem unless you are using equipment that is not isolated or balanced and then you can get noise from cable movements, inserting plugs with the volume up. Hope this helps.