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Re: Zoom R16 - mic preamps (& phantom power)

Subject: Re: Zoom R16 - mic preamps (& phantom power)
From: "Greg ODrobinak" gmo_dunes2
Date: Wed Aug 12, 2009 10:49 am ((PDT))
Dan:

I am not sure where you would get 12VDC from the internals of this unit. Th=
e battery pack outputs 9VDC nominal and the external supply is good for 5VD=
C, so there is obviously some DC power conversion happenning, but we don't =
know what the voltage rails are without a schematic for the unit [does anyo=
ne have this? I would LOVE to see it!]. Also, some microphones are finicky,=
 such as the Okatavas, so they really need to have 48V.

I suspect that Zoom restricted the phantom power to 2 inputs to keep power =
consumption down to a minimum. Assuming that a microphone draws 4 mA of pow=
er at 48VDC, then the power needed is 200 mW. This would translate to rough=
ly 23 mA continous draw on the battery pack, taking the inefficiency of the=
 power conversion into consideration.  This is significant for long-term re=
cording when you are relying on AA batteries for power. If you are using 8 =
mics which draw 4mA each, then our power requirement jumps up to almost 1.6=
 watts. We don't often realize how much power our mics really use and how i=
t impacts our power source! Some mics take as much as 8mA which would doubl=
e the power budget to 3 watts. There go the batteries!

Anyway, I started this post in an effort to (hopefully) get some real specs=
 [read: real measurements] on the self noise of the R16 mic preamps. While =
having more than 2 inputs is a definite plus, they are of questionable bene=
fit to me if they are as noisy as the rest of the Zoom products to date. Al=
l of the web postings so far only state subjective impressions of the pream=
ps and they are rather terse to boot. I was hoping for more definitive info=
 since the R16 has been available in the US for some time.

Raimund, is the R16 available yet to you? Is there a chance you could snag =
one and do the self noise measurement?

Also, if someone could post the procedure for doing the self noise measurem=
ent on an arbitrary recorder's mic preamp, I would be most grateful. I have=
 an idea of how to do it, but I am not certain that my procedure is correct=
.

Thanks!

-Greg O'Drobinak


--- In  Dan Dugan <> wrote:
>
> It's rarely economical to modify consumer goods, but it would probably =

> be only a couple of hundred dollars in labor to hack 12V phantom power =

> into all the inputs, more for true 48V.
>
> -Dan Dugan
>








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