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Re: converting unbalanced signal to balanced and FR-2LE

Subject: Re: converting unbalanced signal to balanced and FR-2LE
From: "Hector Centeno" hmcenteno
Date: Mon Feb 11, 2008 2:35 pm ((PST))
OK! Problem solved. It's the adapters (obviously). I found that pins 1
and 3 were also in contact with the outer barrel of the XLR.
Disassembling the adapter separating the 1/4 input section from the
XLR output section made the noise to stop. Thanks a lot for your
advice.


Hector



On Feb 11, 2008 2:27 PM, Philip Tyler <> wrote:
>
>
>
>
>
>
> Hi Hector
>
>  Just checking, you have turned the phantom power off
>  have you on the FR2 LE? As that could cause problems.
>
>  Wiring the earth / screened to both pins 1 and 3
>  should not cause problems, unless the input is not
>  transformer balanced but electronically balanced. But
>  I would have thought that the FR2 LE had transformers
>  on its input.
>
>  I wire my unbalanced microphones the way I outlined
>  and I have not had any problems.
>
>  If I am wiring up the balanced output of an
>  electronically balanced unit to work into an
>  unbalanced device then you only use pins 2 and 1
>  leaving pin 3 floating.
>
>  Phil
>
>
>
>  --- Hector Centeno <> wrote:
>
>  > Hello,
>  >
>  > Thank you for your responses. Yes, I'm aware that
>  > the 1/4 inputs in
>  > the FR-2LE are line level so the first thing I did
>  > was to use a 1/4
>  > inch to XLR adapter to plug the AT-822 1/4 outputs
>  > (which basically
>  > does what Phil suggested: hot to pin 2, ground to
>  > pin 1 and 3) but to
>  > my surprise I got a loud noise interference
>  > (buzzings that seem to
>  > come from the electronic circuits) mixed with the
>  > audio signal. So
>  > following this advice
>  > http://www.dplay.com/dv/balance/balance.html#cross I
>  > built a
>  > 1/4-female to XLR-male cable soldering the hot (red)
>  > wire to pin 2 and
>  > the ground (white) to pin 3 leaving pin 1
>  > disconnected. Now there is
>  > no noise! But if I touch the connector on the 1/4
>  > end (which is
>  > metallic) I get a soft ground hum. Any suggestions?
>  >
>  > Cheers,
>  >
>  > Hector
>  >
>  >
>  > On Feb 11, 2008 1:19 PM, oryoki2000
>  > <> wrote:
>  > >
>  > >
>  > >
>  > >
>  > >
>  > >
>  > > Hector,
>  > >
>  > > I think you'll have to convert your mic cables to
>  > XLR, and not because
>  > > of the balanced vs unbalanced signal issue.
>  > >
>  > > Page 42 of the FR-2LE manual describes the analog
>  > inputs
>  > >
>  > > "These connectors are "combo" type (both 1/4" and
>  > XLR) and can connect
>  > > an external microphone via the XLR connector or
>  > an external line level
>  > > source via the 1/4" connector."
>  > >
>  > > On page 50, the manual says
>  > >
>  > > "The XLR connection accepts an analog signal
>  > between -50 dBu and -10
>  > > dBu...the phone plug accepts a -10 dBV analog
>  > audio signal."
>  > >
>  > > -10 dBV is equivalent to -7.78 dBu
>  > >
>  > > This says to me that the 1/4" inputs won't work
>  > well with a microphone
>  > > unless the audio source is extremely loud (rock
>  > band, plane taking
>  > > off, huge crashing waves, etc.)
>  > >
>  > > To test this idea, I found an inexpensive Radio
>  > Shack mic with 1/4"
>  > > output in a drawer. I plugged it into my FR-2LE
>  > and started
>  > > recording. I had to talk in a very loud voice, a
>  > shout almost, to
>  > > register a signal.
>  > >
>  > > So the 1/4" input is probably not the right
>  > choice if you're trying to
>  > > capture a natural ambience. It might be just
>  > right to record steam
>  > > locomotives, however!
>  > >
>  > > --oryoki
>  > >
>  > >
>  >
>
>  __________________________________________________________
>  Sent from Yahoo! Mail - a smarter inbox http://uk.mail.yahoo.com
>
>  




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