My Rane preamps provide +15v phantom power. The specs for my new AT4040 say +48v.

What are the ramifications of using +15v phantom power with the AT4040 mic?

I found this in my Rane Tech Notes (#148)

There is a huge myth circulating that microphones sound better running from 48 volts, as opposed to, say, 12 volts, or that you can increase the dynamic range of a microphone by using higher phantom power.

For the overwhelming majority of microphones both of these beliefs are false. Most condenser microphones require phantom power in the range of 12-48 VDC, with many extending the range to 9-52 VDC, leaving only a very few that actually require just 48 VDC.

The reason is that internally most designs use some form of current source to drive a low voltage zener (usually 5 volts; sometimes higher) which determines the polarization voltage and powers the electronics.

The significance is that neither runs off the raw phantom power, they both are powered from a fixed and regulated low voltage source inside the mic. Increasing the phantom power voltage is never seen by the microphone element or electronics, it only increases the voltage across the current source.

But there are exceptions, so check the manufacturer, and don't make assumptions based on hearsay.

[ August 30, 2003, 12:31 PM: Message edited by: bgavin ]