From: David Martin <>
>
>
> I recently bought an Aquarian Audio H2-XLR hydrophone and found a problem
> that I don't understand.
>
> The H2-XLR requires phantom power. When I supplied the 48V power from my
> Marantz PMD670, the noise level was so high the hydrophone was absolutely
> unusable, and I thought I'd have to send it back. However, when I
> supplied 48V power with a Sennheiser MZA14 the noise level was amazingly
> reduced. Does anyone have any idea why this should happen? I have had
> no trouble powering MKH20s, an MKH30 or MKH60 from the PMD670.
Only thought I have is maybe they are taking the phantom power off only
one leg and thus unbalancing the power. Any noise in the phantom power
would then show up on the signal. I've not heard if anyone has checked
the noise on each leg of the PMD670's phantom power. Some battery
operated phantom power is not all that clean and depends on a full
balanced configuration to filter most of it out.
I know the MZA14 has clean phantom, I have a couple of those and tested
them the same time I was testing my Portadisc (which also has clean power)
I have one of the Aquarian hydrophones here, but it's one of the ones
with a 9 volt battery supply. I would not mind modifying it for phantom
power sometime. Currently there are no unwanted noises from it and it
works reasonably well.
Walt
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