Doepfer

Hi,

  I would like to appeal to anyone with experience in eradicating a
probable ground loop.  I've just done a bit of upgrading in my studio,
and I've developed a nasty buzzing in my system.  I've narrowed it
down to the interplay between Logic 7 and my analogue synth.  Of note
is that I have not changed anything inside the synth since before the
upgrade and that the problem exists even when the synth is turned off
but not when it is unplugged from the wall.  In fact, I've just been
jiggling about with the plug and the buzz come back as soon as the
earth pin of the plug makes contact.

  The problem also only exists when Logic is running but not when i
run things like iTunes etc.  It can also be controlled by the mixer;
turning down the channel volume or EQing it out work.  I've also gone
around turning off and unplugging everything except the computer,
synth and mixer, but the buzz remains.

Can anyone help?

Yours Aye

Stuadh

No guarantee that this will fix it, but I have a few Ebtech hum eliminators. They are line level isolation transformers. They won't fix every hum, and in one case it introduced a hum, but they've worked for me more often than not.

Other than that, I would check your mains outlets for open ground as a start.

Good luck.

-n



      ____________________________________________________________________________________
Looking for last minute shopping deals?  
Find them fast with Yahoo! Search.  http://tools.search.yahoo.com/newsearch/category.php?category=shopping

> Hi,
>
> I would like to appeal to anyone with experience in eradicating a
> probable ground loop. I've just done a bit of upgrading in my studio,
> and I've developed a nasty buzzing in my system. I've narrowed it
> down to the interplay between Logic 7 and my analogue synth. Of note
> is that I have not changed anything inside the synth since before the
> upgrade and that the problem exists even when the synth is turned off
> but not when it is unplugged from the wall. In fact, I've just been
> jiggling about with the plug and the buzz come back as soon as the
> earth pin of the plug makes contact.
>
> The problem also only exists when Logic is running but not when i
> run things like iTunes etc. It can also be controlled by the mixer;
> turning down the channel volume or EQing it out work. I've also gone
> around turning off and unplugging everything except the computer,
> synth and mixer, but the buzz remains.
>
> Can anyone help?
>
> Yours Aye
>
> Stuadh

We had similar problems when we changed the arrangement of the A-100 demo
system, mixer and computer. The solution we found was the usage of a passive
DI box between mixer and computer.

Best wishes
Dieter Doepfer

if this only happens when logic is running, you might want to take a
closer look at the software routing. have you tried your old
template/autoload?

i had a midi-feedback loop once that was provided by (new) logic's own
autoload in combination with the rest of my setup. using my old
autoload solved it.

hth,

stu

--- In Doepfer_a100@yahoogroups.com, <hardware@...> wrote:
>
> > Hi,
> >
> > I would like to appeal to anyone with experience in eradicating a
> > probable ground loop. I've just done a bit of upgrading in my studio,
> > and I've developed a nasty buzzing in my system. I've narrowed it
> > down to the interplay between Logic 7 and my analogue synth. Of note
> > is that I have not changed anything inside the synth since before the
> > upgrade and that the problem exists even when the synth is turned off
> > but not when it is unplugged from the wall. In fact, I've just been
> > jiggling about with the plug and the buzz come back as soon as the
> > earth pin of the plug makes contact.
> >
> > The problem also only exists when Logic is running but not when i
> > run things like iTunes etc. It can also be controlled by the mixer;
> > turning down the channel volume or EQing it out work. I've also gone
> > around turning off and unplugging everything except the computer,
> > synth and mixer, but the buzz remains.
> >
> > Can anyone help?
> >
> > Yours Aye
> >
> > Stuadh
> 
> We had similar problems when we changed the arrangement of the A-100
demo
> system, mixer and computer. The solution we found was the usage of a
passive

> DI box between mixer and computer.
> 
> Best wishes
> Dieter Doepfer
>

Hi

we had similar problems last week within a large live setup. Around 15 
musicians with computers, lots of synths and softsynth, all mixed to 
submixers, which are led to a main mix. The lenght of the power and 
audio cables are 6 meters for the most musicians at least.

Though this sounds like a bunch of humm traps the most participians do 
not have real problems, but two guys:
Finally we could track down that these two are using USB-Audiointerfaces 
where the interfaces are powered by the USB port, not by an external 
supply. This means that you have the dirty ground of the digital domain 
as audioground.

Our solution now was simply to forbid this type of audiointerfaces.

Florian

stuadh wrote:

> Hi,
> 
>   I would like to appeal to anyone with experience in eradicating a
> probable ground loop.  I've just done a bit of upgrading in my studio,
> and I've developed a nasty buzzing in my system.  I've narrowed it
> down to the interplay between Logic 7 and my analogue synth.  Of note
> is that I have not changed anything inside the synth since before the
> upgrade and that the problem exists even when the synth is turned off
> but not when it is unplugged from the wall.  In fact, I've just been
> jiggling about with the plug and the buzz come back as soon as the
> earth pin of the plug makes contact.
> 
>   The problem also only exists when Logic is running but not when i
> run things like iTunes etc.  It can also be controlled by the mixer;
> turning down the channel volume or EQing it out work.  I've also gone
> around turning off and unplugging everything except the computer,
> synth and mixer, but the buzz remains.
> 
> Can anyone help?
> 
> Yours Aye
> 
> Stuadh
> 
> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 
> 

-- 
Florian Anwander                  |ConSol
Tel.   +49(89)45841-133           |Consulting&Solutions Software GmbH
Fax    +49(89)45841-111           |Franziskanerstr. 38, D-81669 München
email: florian.anwander@consol.de |http://www.consol.de

if you are in the US try one of those cheap plug adapters from 3 ends
to two  on your computer's power cable plug, (so the 3rd circular ends
up removed from the equation) this solved a problem I had before with
my laptop causing ground noise. but might be more of a temporary
solution. I just don't use the laptop anymore :)      


Carlos.

--- In Doepfer_a100@yahoogroups.com, "Anwander, Florian"
<Florian.Anwander@...> wrote:
>
> Hi
> 
> we had similar problems last week within a large live setup. Around 15 
> musicians with computers, lots of synths and softsynth, all mixed to 
> submixers, which are led to a main mix. The lenght of the power and 
> audio cables are 6 meters for the most musicians at least.
> 
> Though this sounds like a bunch of humm traps the most participians do 
> not have real problems, but two guys:
> Finally we could track down that these two are using
USB-Audiointerfaces 

> where the interfaces are powered by the USB port, not by an external 
> supply. This means that you have the dirty ground of the digital domain 
> as audioground.
> 
> Our solution now was simply to forbid this type of audiointerfaces.
> 
> Florian
> 
> stuadh wrote:
> 
> > Hi,
> > 
> >   I would like to appeal to anyone with experience in eradicating a
> > probable ground loop.  I've just done a bit of upgrading in my studio,
> > and I've developed a nasty buzzing in my system.  I've narrowed it
> > down to the interplay between Logic 7 and my analogue synth.  Of note
> > is that I have not changed anything inside the synth since before the
> > upgrade and that the problem exists even when the synth is turned off
> > but not when it is unplugged from the wall.  In fact, I've just been
> > jiggling about with the plug and the buzz come back as soon as the
> > earth pin of the plug makes contact.
> > 
> >   The problem also only exists when Logic is running but not when i
> > run things like iTunes etc.  It can also be controlled by the mixer;
> > turning down the channel volume or EQing it out work.  I've also gone
> > around turning off and unplugging everything except the computer,
> > synth and mixer, but the buzz remains.
> > 
> > Can anyone help?
> > 
> > Yours Aye
> > 
> > Stuadh
> > 
> > 
> > 
> >  
> > Yahoo! Groups Links
> > 
> > 
> > 
> > 
> 
> -- 
> Florian Anwander                  |ConSol
> Tel.   +49(89)45841-133           |Consulting&Solutions Software GmbH
> Fax    +49(89)45841-111           |Franziskanerstr. 38, D-81669 München
> email: florian.anwander@... |http://www.consol.de
>

Thanks again, Dieter, Florian et al.

  I'm going to try a DI box.  The mixer is the last thing that changed
before the problem appeared.  Although it might not be the only cause,
it must be a part of it.  The mixer is being powered by its own power
source, not USB and I'm using the same old Autoload and songs within
logic.

Cheers for the help, 

  Stuadh



--- In Doepfer_a100@yahoogroups.com, <hardware@...> wrote:
>
> > Hi,
> >
> > I would like to appeal to anyone with experience in eradicating a
> > probable ground loop. I've just done a bit of upgrading in my studio,
> > and I've developed a nasty buzzing in my system. I've narrowed it
> > down to the interplay between Logic 7 and my analogue synth. Of note
> > is that I have not changed anything inside the synth since before the
> > upgrade and that the problem exists even when the synth is turned off
> > but not when it is unplugged from the wall. In fact, I've just been
> > jiggling about with the plug and the buzz come back as soon as the
> > earth pin of the plug makes contact.
> >
> > The problem also only exists when Logic is running but not when i
> > run things like iTunes etc. It can also be controlled by the mixer;
> > turning down the channel volume or EQing it out work. I've also gone
> > around turning off and unplugging everything except the computer,
> > synth and mixer, but the buzz remains.
> >
> > Can anyone help?
> >
> > Yours Aye
> >
> > Stuadh
> 
> We had similar problems when we changed the arrangement of the A-100
demo
> system, mixer and computer. The solution we found was the usage of a
passive

> DI box between mixer and computer.
> 
> Best wishes
> Dieter Doepfer
>

If all equipment is made according to the AES48 standard, no
groundloop problems would occur. 
here you can download the Aes48 standard:
http://campuspa.com/downloads/aes48-2005-f.pdf

Groundloops will alway's be pressent when connecting equipment. Their
influence on the audio signal can be big, small or non at all.

Most modern balanced equipment has the shield connected to the signal
earth. (This is to connect unbalanced equipment without much hum, but
when you make a balanced connection lots of hum will happen. known as
the pin 1 problem) This is not correct, the shield should be connected
to the chassis. The simplest solution is to get a soldering iron and
connect the shield to the chassis. When connecting correctly balanced
equipment with unballanced equipment a DI box should be used.




--- In Doepfer_a100@yahoogroups.com, "stuadh" <stuadh@...> wrote:
>
> Thanks again, Dieter, Florian et al.
> 
>   I'm going to try a DI box.  The mixer is the last thing that changed
> before the problem appeared.  Although it might not be the only cause,
> it must be a part of it.  The mixer is being powered by its own power
> source, not USB and I'm using the same old Autoload and songs within
> logic.
> 
> Cheers for the help, 
> 
>   Stuadh
> 
> 
> 
> --- In Doepfer_a100@yahoogroups.com, <hardware@> wrote:
> >
> > > Hi,
> > >
> > > I would like to appeal to anyone with experience in eradicating a
> > > probable ground loop. I've just done a bit of upgrading in my
studio,
> > > and I've developed a nasty buzzing in my system. I've narrowed it
> > > down to the interplay between Logic 7 and my analogue synth. Of note
> > > is that I have not changed anything inside the synth since
before the
> > > upgrade and that the problem exists even when the synth is
turned off

> > > but not when it is unplugged from the wall. In fact, I've just been
> > > jiggling about with the plug and the buzz come back as soon as the
> > > earth pin of the plug makes contact.
> > >
> > > The problem also only exists when Logic is running but not when i
> > > run things like iTunes etc. It can also be controlled by the mixer;
> > > turning down the channel volume or EQing it out work. I've also gone
> > > around turning off and unplugging everything except the computer,
> > > synth and mixer, but the buzz remains.
> > >
> > > Can anyone help?
> > >
> > > Yours Aye
> > >
> > > Stuadh
> > 
> > We had similar problems when we changed the arrangement of the A-100
> demo
> > system, mixer and computer. The solution we found was the usage of a
> passive
> > DI box between mixer and computer.
> > 
> > Best wishes
> > Dieter Doepfer
> >
>

Hi all,

  thanks for your answers.  I got the DI Box, one recommended on the
SOS Website (ART Cleanbox II) and not the cheapest one around.  Not
one bit of difference.  I connected up the earths of all the cables
again (and again no difference.  This is definitely a 
Mixer-Analogue Synth problem as removing any connection between the to
makes the problem disappear.  By the way, this isn't a small problem -
it's really loud!

Can anyone offer the next step as the synth is currently unusable?

Your in desperation

Stuadh

--- In Doepfer_a100@yahoogroups.com, "Carlos" <bushwick@...> wrote:
>
> 
> if you are in the US try one of those cheap plug adapters from 3 ends
> to two  on your computer's power cable plug, (so the 3rd circular ends
> up removed from the equation) this solved a problem I had before with
> my laptop causing ground noise. but might be more of a temporary
> solution. I just don't use the laptop anymore :)      
> 
> 
> Carlos.
> 
> --- In Doepfer_a100@yahoogroups.com, "Anwander, Florian"
> <Florian.Anwander@> wrote:
> >
> > Hi
> > 
> > we had similar problems last week within a large live setup.
Around 15 
> > musicians with computers, lots of synths and softsynth, all mixed to 
> > submixers, which are led to a main mix. The lenght of the power and 
> > audio cables are 6 meters for the most musicians at least.
> > 
> > Though this sounds like a bunch of humm traps the most
participians do 
> > not have real problems, but two guys:
> > Finally we could track down that these two are using
> USB-Audiointerfaces 
> > where the interfaces are powered by the USB port, not by an external 
> > supply. This means that you have the dirty ground of the digital
domain 
> > as audioground.
> > 
> > Our solution now was simply to forbid this type of audiointerfaces.
> > 
> > Florian
> > 
> > stuadh wrote:
> > 
> > > Hi,
> > > 
> > >   I would like to appeal to anyone with experience in eradicating a
> > > probable ground loop.  I've just done a bit of upgrading in my
studio,
> > > and I've developed a nasty buzzing in my system.  I've narrowed it
> > > down to the interplay between Logic 7 and my analogue synth.  Of
note
> > > is that I have not changed anything inside the synth since
before the
> > > upgrade and that the problem exists even when the synth is
turned off
> > > but not when it is unplugged from the wall.  In fact, I've just been
> > > jiggling about with the plug and the buzz come back as soon as the
> > > earth pin of the plug makes contact.
> > > 
> > >   The problem also only exists when Logic is running but not when i
> > > run things like iTunes etc.  It can also be controlled by the mixer;
> > > turning down the channel volume or EQing it out work.  I've also
gone
> > > around turning off and unplugging everything except the computer,
> > > synth and mixer, but the buzz remains.
> > > 
> > > Can anyone help?
> > > 
> > > Yours Aye
> > > 
> > > Stuadh
> > > 
> > > 
> > > 
> > >  
> > > Yahoo! Groups Links
> > > 
> > > 
> > > 
> > > 
> > 
> > -- 
> > Florian Anwander                  |ConSol
> > Tel.   +49(89)45841-133           |Consulting&Solutions Software GmbH
> > Fax    +49(89)45841-111           |Franziskanerstr. 38, D-81669
München

> > email: florian.anwander@ |http://www.consol.de
> >
>

Howdy,

Get a power-regenerating UPS, it'll output a pure sinewave back out regardless of what your utility power does.

~Danny

On Wed, Feb 20, 2008 at 10:37:30PM -0000, stuadh wrote:
> Hi all,
> 
>   thanks for your answers.  I got the DI Box, one recommended on the
> SOS Website (ART Cleanbox II) and not the cheapest one around.  Not
> one bit of difference.  I connected up the earths of all the cables
> again (and again no difference.  This is definitely a 
> Mixer-Analogue Synth problem as removing any connection between the to
> makes the problem disappear.  By the way, this isn't a small problem -
> it's really loud!
> 
> Can anyone offer the next step as the synth is currently unusable?
> 
> Your in desperation
> 
> Stuadh
> 
> --- In Doepfer_a100@yahoogroups.com, "Carlos" <bushwick@...> wrote:
> >
> > 
> > if you are in the US try one of those cheap plug adapters from 3 ends
> > to two  on your computer's power cable plug, (so the 3rd circular ends
> > up removed from the equation) this solved a problem I had before with
> > my laptop causing ground noise. but might be more of a temporary
> > solution. I just don't use the laptop anymore :)      
> > 
> > 
> > Carlos.
> > 
> > --- In Doepfer_a100@yahoogroups.com, "Anwander, Florian"
> > <Florian.Anwander@> wrote:
> > >
> > > Hi
> > > 
> > > we had similar problems last week within a large live setup.
> Around 15 
> > > musicians with computers, lots of synths and softsynth, all mixed to 
> > > submixers, which are led to a main mix. The lenght of the power and 
> > > audio cables are 6 meters for the most musicians at least.
> > > 
> > > Though this sounds like a bunch of humm traps the most
> participians do 
> > > not have real problems, but two guys:
> > > Finally we could track down that these two are using
> > USB-Audiointerfaces 
> > > where the interfaces are powered by the USB port, not by an external 
> > > supply. This means that you have the dirty ground of the digital
> domain 
> > > as audioground.
> > > 
> > > Our solution now was simply to forbid this type of audiointerfaces.
> > > 
> > > Florian
> > > 
> > > stuadh wrote:
> > > 
> > > > Hi,
> > > > 
> > > >   I would like to appeal to anyone with experience in eradicating a
> > > > probable ground loop.  I've just done a bit of upgrading in my
> studio,
> > > > and I've developed a nasty buzzing in my system.  I've narrowed it
> > > > down to the interplay between Logic 7 and my analogue synth.  Of
> note
> > > > is that I have not changed anything inside the synth since
> before the
> > > > upgrade and that the problem exists even when the synth is
> turned off
> > > > but not when it is unplugged from the wall.  In fact, I've just been
> > > > jiggling about with the plug and the buzz come back as soon as the
> > > > earth pin of the plug makes contact.
> > > > 
> > > >   The problem also only exists when Logic is running but not when i
> > > > run things like iTunes etc.  It can also be controlled by the mixer;
> > > > turning down the channel volume or EQing it out work.  I've also
> gone
> > > > around turning off and unplugging everything except the computer,
> > > > synth and mixer, but the buzz remains.
> > > > 
> > > > Can anyone help?
> > > > 
> > > > Yours Aye
> > > > 
> > > > Stuadh
> > > > 
> > > > 
> > > > 
> > > >  
> > > > Yahoo! Groups Links
> > > > 
> > > > 
> > > > 
> > > > 
> > > 
> > > -- 
> > > Florian Anwander                  |ConSol
> > > Tel.   +49(89)45841-133           |Consulting&Solutions Software GmbH
> > > Fax    +49(89)45841-111           |Franziskanerstr. 38, D-81669
> M?nchen
> > > email: florian.anwander@ |http://www.consol.de
> > >
> >
> 
> 
> 
> 
>  
> Yahoo! Groups Links
> 
> 
>

What happens if you disconnect the shield from DI to mixer?

If this reduces the noise, you should get a soldering iron and change
the signal earth with chassis earth from mixer.

If it does not reduce noise its not a groundloop problem.

Hope it helps.


--- In Doepfer_a100@yahoogroups.com, "stuadh" <stuadh@...> wrote:
>
> Hi all,
> 
>   thanks for your answers.  I got the DI Box, one recommended on the
> SOS Website (ART Cleanbox II) and not the cheapest one around.  Not
> one bit of difference.  I connected up the earths of all the cables
> again (and again no difference.  This is definitely a 
> Mixer-Analogue Synth problem as removing any connection between the to
> makes the problem disappear.  By the way, this isn't a small problem -
> it's really loud!
> 
> Can anyone offer the next step as the synth is currently unusable?
> 
> Your in desperation
> 
> Stuadh
> 
> --- In Doepfer_a100@yahoogroups.com, "Carlos" <bushwick@> wrote:
> >
> > 
> > if you are in the US try one of those cheap plug adapters from 3 ends
> > to two  on your computer's power cable plug, (so the 3rd circular ends
> > up removed from the equation) this solved a problem I had before with
> > my laptop causing ground noise. but might be more of a temporary
> > solution. I just don't use the laptop anymore :)      
> > 
> > 
> > Carlos.
> > 
> > --- In Doepfer_a100@yahoogroups.com, "Anwander, Florian"
> > <Florian.Anwander@> wrote:
> > >
> > > Hi
> > > 
> > > we had similar problems last week within a large live setup.
> Around 15 
> > > musicians with computers, lots of synths and softsynth, all
mixed to 
> > > submixers, which are led to a main mix. The lenght of the power and 
> > > audio cables are 6 meters for the most musicians at least.
> > > 
> > > Though this sounds like a bunch of humm traps the most
> participians do 
> > > not have real problems, but two guys:
> > > Finally we could track down that these two are using
> > USB-Audiointerfaces 
> > > where the interfaces are powered by the USB port, not by an
external 
> > > supply. This means that you have the dirty ground of the digital
> domain 
> > > as audioground.
> > > 
> > > Our solution now was simply to forbid this type of audiointerfaces.
> > > 
> > > Florian
> > > 
> > > stuadh wrote:
> > > 
> > > > Hi,
> > > > 
> > > >   I would like to appeal to anyone with experience in
eradicating a
> > > > probable ground loop.  I've just done a bit of upgrading in my
> studio,
> > > > and I've developed a nasty buzzing in my system.  I've narrowed it
> > > > down to the interplay between Logic 7 and my analogue synth.  Of
> note
> > > > is that I have not changed anything inside the synth since
> before the
> > > > upgrade and that the problem exists even when the synth is
> turned off
> > > > but not when it is unplugged from the wall.  In fact, I've
just been
> > > > jiggling about with the plug and the buzz come back as soon as the
> > > > earth pin of the plug makes contact.
> > > > 
> > > >   The problem also only exists when Logic is running but not
when i
> > > > run things like iTunes etc.  It can also be controlled by the
mixer;
> > > > turning down the channel volume or EQing it out work.  I've also
> gone
> > > > around turning off and unplugging everything except the computer,
> > > > synth and mixer, but the buzz remains.
> > > > 
> > > > Can anyone help?
> > > > 
> > > > Yours Aye
> > > > 
> > > > Stuadh
> > > > 
> > > > 
> > > > 
> > > >  
> > > > Yahoo! Groups Links
> > > > 
> > > > 
> > > > 
> > > > 
> > > 
> > > -- 
> > > Florian Anwander                  |ConSol
> > > Tel.   +49(89)45841-133           |Consulting&Solutions Software
GmbH

> > > Fax    +49(89)45841-111           |Franziskanerstr. 38, D-81669
> München
> > > email: florian.anwander@ |http://www.consol.de
> > >
> >
>