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2. Re: R-44 issue-geek reply

Subject: 2. Re: R-44 issue-geek reply
From: "Jez" tempjez
Date: Sun Jun 24, 2012 10:19 am ((PDT))
thanks for this !

it comes as a surprise that the DPA adaptors aren't doing the job - it'll b=
e interesting to see what they have to say about this issue.

in case they can't come up with anything does anyone have a suggestion for =
a different adaptor for the DPA4060's ?

oh & the Telinga stereo dat also picks up some digital noise !

I think for me the most worrying thing about all this is that if, apparentl=
y, ever other recorder manufacturer has managed to make their recorders wit=
h circuits that don't have these issues with the DPA's or the Telinga for e=
xample, then its strange that Roland can't do it too.

ta.


--- In  "Raimund" <> wrot=
e:
>
> Hi Jez,
>
> I just did a quick test with a Roland R-26 in order to investigate the qu=
ality of its phantom power supply circuit:
>
> I made a simple dummy load consisting of a 150 ohm resistor connected bet=
ween the XLR pins 2 and 3. In order to create a load on the phantom power s=
upply, I also added two 2.2 kohm resistors, one connected between pin 2 and=
 pin 1 (ground) and the other from pin 3 and pin 1. This creates a current =
flow of about 10 mA (48V / (6.8 + 2.2 kohm) * 2).
>
> Here is a recording with that dummy load with the phantom power switched =
off (at the maximum gain): http://www.avisoft.com/scratch/R26_0001_1.wav
>
> I then activated the phantom power on the recorder (with both 2k2 resisto=
rs connected, simulating a balanced microphone circuit):
> http://www.avisoft.com/scratch/R26_0002_1.wav
>
> Finally, I removed one of the 2k2 load resistors, which simulates an unba=
lanced microphone circuit:
> http://www.avisoft.com/scratch/R26_0003_1.wav
>
> The last recording reveals that the phantom power supply of the recorder =
contains indeed some digital noise that becomes audible, once a poorly desi=
gned (unbalanced) microphone is attached to the recorder (a balanced circui=
t would eliminate the phantom power noise).
>
> So, I believe that you could fix the problem with your DPA microphones by=
 using a better phantom power adapter that draws the same current from pin =
2 and 3.
>
> Regards,
> Raimund
>
>
>
>
> --- In  "Jez" <tempjez@> wrote:
> >
> > ha - no.  if you take a listen to the samples on the links you can hear=
 that its across the board on both recorders & not the same as a mobile pho=
ne 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 =
the DAD6001s?
> > > >
> > > > let me know if you want me to post a clip.
> > >
> >
>








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