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1. Re: R-44 issue-geek reply

Subject: 1. Re: R-44 issue-geek reply
From: "Raimund" animalsounds
Date: Sun Jun 24, 2012 7:40 am ((PDT))
Hi Jez,

I just did a quick test with a Roland R-26 in order to investigate the qual=
ity of its phantom power supply circuit:

I made a simple dummy load consisting of a 150 ohm resistor connected betwe=
en the XLR pins 2 and 3. In order to create a load on the phantom power sup=
ply, I also added two 2.2 kohm resistors, one connected between pin 2 and p=
in 1 (ground) and the other from pin 3 and pin 1. This creates a current fl=
ow of about 10 mA (48V / (6.8 + 2.2 kohm) * 2).

Here is a recording with that dummy load with the phantom power switched of=
f (at the maximum gain):

I then activated the phantom power on the recorder (with both 2k2 resistors=
 connected, simulating a balanced microphone circuit):

Finally, I removed one of the 2k2 load resistors, which simulates an unbala=
nced microphone circuit:

The last recording reveals that the phantom power supply of the recorder co=
ntains indeed some digital noise that becomes audible, once a poorly design=
ed (unbalanced) microphone is attached to the recorder (a balanced circuit =
would eliminate the phantom power noise).

So, I believe that you could fix the problem with your DPA microphones by u=
sing a better phantom power adapter that draws the same current from pin 2 =
and 3.


--- In  "Jez" <> wrote:
> ha - no.  if you take a listen to the samples on the links you can hear t=
hat its across the board on both recorders & not the same as a mobile phone=
 signal / sound. definitely the display panel on the recorders.
> --- In  Dan Dugan <dan@> wrote:
> >
> > Do you have a mobile phone on your person?
> >
> > -Dan
> >
> > On Jun 23, 2012, at 6:05 AM, ac wrote:
> >
> > > well i'm definitely NOT hearing this on my R26 and 4060s.
> > >
> > > can we conclude that it's perhaps related to the revised design of th=
e DAD6001s?
> > >
> > > let me know if you want me to post a clip.
> >

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