I love your mag and always look forward to reading new issues on my iPad! I have a question concerning phantom power that I hope you can help me with: I have some of my condenser mics running into more than one preamp, via a Radial JS2 [passive mic splitter], with only one of the preamps applying phantom power. Is this the way it should be, and could it damage the mic or preamps in any way if both preamps are set to supply phantom power at the same time?
Martin Yap, via email
SOS Technical Editor Hugh Robjohns replies: You are using the device correctly: the preamp supplying phantom power should be connected to the ‘Direct Thru 1’ output, and the second preamp should connect to either the ‘Direct Thru 2’ or the ‘Isolated’ output. The ‘Direct Thru 1’ XLR passes phantom power directly to the mic.
There is no risk of any damage being caused (to mic or preamps) should you switch on the phantom power on both connected preamps, but doing so is pointless and you might forget to turn off both when connecting/disconnecting mics, resulting in an unexpected crack through your monitor speakers!
The Radial JS2 has one transformer-isolated output, which cannot pass phantom power to the mic at all and is intended to provide an electrically isolated feed for a separate recording system. The second (‘Direct Thru 2’) can pass phantom power, but only if the ground-lift switch is not activated. As I said above, the ‘Direct Thru 1’ output is intended to connect with the source of phantom power.