[SI-LIST] Re: Audio And Fan Circuits interference

Hi Martin,


Martin Euredjian wrote:

> A few questions:
>
> 1- What is the power supply topology?

        The fan is is running out of a separate 12 v line than the audio.
        The audio requires a 5v source wich is regulated out of a 12v line
from the main supply.

>
> 2- Is the fan (fans?) on the same power supply as the audio circuits?

     See answer 1.

>
>
> 3- Where is the fan connector (I presume) located with respect to the =
> power
> inpu and the audio circuitry?

     The fan and audio circuits are on  different PCBs, several inches away.

>
>
> 4- How is the grounding handled for both the fan and audio circuits?
> Moating?  Plane?  Discrete traces?

   The audio analog section is isolated from the digital section by a Moat,
    the fan circuit is on the digital section.

>
>
> 5- What exactly is your "fan controller"?  How is it implemented?

     DS1780 + OPAMP+ Pchannel FET + FAN

>
> 6- Are there any capacitors right at the connector pins?

     No.

>
>
> 7- Have you tried extending the fan cabled by, say, three feet or more =
> in
> order to eliminate the magnetic coupling/near-range RFI as a =
> possibility?
>

Yes, it did not help.

>
> 8- Have you tried wrapping several turns of the fan wires around a =
> toroid?
>

Yes, it did not help.

>
> 9- Have you tried to connect the fan/s directly to the power source?

No.

>
>
> 10- Have you measured the noise?  What frequency is it?  Spectrum?=20

No

>
>
> 11- Do you really need a fan?  (just kidding)
>     But, seriously now, heat-pipe technology can be a very elegant =
> solution
> for the right application.
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Martin Euredjian
> eCinema Systems, Inc.
> voice: 661-305-9320
> fax: 661-775-4876
> martin@xxxxxxxxxxxxxx
> www.ecinemasys.com
> =20
> =20
> =20
> =20
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] =
> On
> Behalf Of Brahim Koudssi
> Sent: Friday, February 14, 2003 8:50 AM
> To: bart.bouma@xxxxxxxxx
> Cc: si-list@xxxxxxxxxxxxx; si-list-bounce@xxxxxxxxxxxxx;
> jonpowell@xxxxxxxxxxxx
> Subject: [SI-LIST] Re: Audio And Fan Circuits interference
>
> Hi,
>
> Thanks for you response.
>
> The motor is brushless, the controller is not PWM.
>
> Brahim
>
> Bart Bouma wrote:
>
> > Hi,
> >
> > Does the motor have brushes? If so the motor can produce a lot of EMI.
> > Filtering this motor or taking a brushless one would solve your =
> problem, I
> > think.
> >
> > Another cause can be the controller circuit. Is it a PWM-controller?
> >
> > Bart
> >
> >
> >           "Jon Powell"
> >           <jonpowell@xxxxxxxxxxxx>           To:     =
> <brahim@xxxxxxxxxxxx>
> >                                               <si-list@xxxxxxxxxxxxx>
> >           13-02-03 17:45                     cc:
> >           Sent by:                           Subject:     [SI-LIST] =
> Re:
> Audio And Fan Circuits interference
> >           si-list-bounce@xxxxxxxxxxxxx     Category:
> >
> >
> >
> >           Please respond to jonpowell
> >
> >
> >
> > Does the fan circuit share VCC and GND with your audio?
> > That is a common source of noise.
> >
> > jon
> >
> > -----Original Message-----
> > From: si-list-bounce@xxxxxxxxxxxxx
> > [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Brahim Koudssi
> > Sent: Thursday, February 13, 2003 6:53 AM
> > To: si-list@xxxxxxxxxxxxx
> > Subject: [SI-LIST] Audio And Fan Circuits interference
> >
> > Hello,
> >
> > I have designed a board that consists of an audio circuit and a fan
> > controller circuit.
> > When the fan is running it induces audible noise in the audio circuit, =
> I
> > can hear in the speakers the fan spinning.
> > Can anyone please address the following questions:
> >
> > 1. How's the fan audible noise getting into the audio?
> > 2. How can I get rid of this interference?
> >
> > Thanks,
> > Brahim
> >
> > ------------------------------------------------------------------
> > To unsubscribe from si-list:
> > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> >
> > or to administer your membership from a web page, go to:
> > http://www.freelists.org/webpage/si-list
> >
> > For help:
> > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> >
> > List archives are viewable at:
> >                      http://www.freelists.org/archives/si-list
> > or at our remote archives:
> >                      http://groups.yahoo.com/group/si-list/messages
> > Old (prior to June 6, 2001) list archives are viewable at:
> >                      http://www.qsl.net/wb6tpu
> >
> > ------------------------------------------------------------------
> > To unsubscribe from si-list:
> > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> >
> > or to administer your membership from a web page, go to:
> > http://www.freelists.org/webpage/si-list
> >
> > For help:
> > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> >
> > List archives are viewable at:
> >                      http://www.freelists.org/archives/si-list
> > or at our remote archives:
> >                      http://groups.yahoo.com/group/si-list/messages
> > Old (prior to June 6, 2001) list archives are viewable at:
> >                      http://www.qsl.net/wb6tpu
> >
> > ------------------------------------------------------------------
> > To unsubscribe from si-list:
> > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> >
> > or to administer your membership from a web page, go to:
> > http://www.freelists.org/webpage/si-list
> >
> > For help:
> > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> >
> > List archives are viewable at:
> >                 http://www.freelists.org/archives/si-list
> > or at our remote archives:
> >                 http://groups.yahoo.com/group/si-list/messages
> > Old (prior to June 6, 2001) list archives are viewable at:
> >                 http://www.qsl.net/wb6tpu
> >
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> http://www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
> List archives are viewable at:    =20
>                 http://www.freelists.org/archives/si-list
> or at our remote archives:
>                 http://groups.yahoo.com/group/si-list/messages=20
> Old (prior to June 6, 2001) list archives are viewable at:
>                 http://www.qsl.net/wb6tpu
>  =20
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> http://www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
> List archives are viewable at:
>                 http://www.freelists.org/archives/si-list
> or at our remote archives:
>                 http://groups.yahoo.com/group/si-list/messages
> Old (prior to June 6, 2001) list archives are viewable at:
>                 http://www.qsl.net/wb6tpu
>

------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: