I recently got a Zoom F8n Pro recorder and noticed when using phantom-powered mics that if a channel is switched off because I don’t wish to record on it for the time being, when I switch it back on, the level jumps and I get a loud thump in my headphones. I’m worried that it may not be good for the mics. Is this normal behaviour or have I got a faulty unit?
SOS Forum post
SOS Technical Editor Hugh Robjohns replies: I suspect this is dependent on the behaviour of specific mics when power is removed and reinstated. I checked my own F8n Pro with a Beyerdynamic MC 840 (which I know to be well behaved in respect of its power‑up behaviour) attached to channel 1 and didn’t get any loud ‘plops’ at all. When I re‑armed the channel, there was a second or so of hiss and then the mic faded in and worked normally. But I have other mics that I know very well do generate loud plops and splats when phantom is applied, which is why I always keep input gains minimised and monitoring muted when connecting and powering mics.
By toggling the track arm button you’re effectively applying power to a mic with the preamp gain turned up.
So I don’t think the Zoom is faulty; I suspect you just happen to be using a mic that makes loud noises when phantom power is applied, which is quite common. By toggling the track arm button you’re effectively applying power to a mic with the preamp gain turned up. The good news is that phantom power‑up pops won’t damage the mic or the recorder (or your headphones). If it bothers you, I would recommend turning the input gain down before re‑engaging the track arm, or muting the headphones.