12 Aug
2008
12 Aug
'08
11:18 p.m.
I got m Tascam US-122 it works fine, the mixers for it dont work in
Qamix and gnomealsamixer, when I choose the usx2y soundcard the mixers
are blank, nothing there. IS that suppost to happen?
ANyways, I am getting noise from my KRK Rokit powered 5 speakers,
headphones in the tascam gives me no noise, then I plug from the
headphones output of the tascam to the speakers and I get noise! So I
think it might have something to do with the speakers?
The noise starts when I plug the USB for the tascam in, even when its
not plugged in and just touches the metal it makes the noise.
When I unplug my AC for my laptop, the noise stops... WHen add
brightness to my laptop screen I get less noise...
Does anyone have any solutions, more troubleshooting tips? Thanks.
12 Aug
12 Aug
11:26 p.m.
Quoth Shawn Wallis at 2008-08-13 10:48...
...> Does anyone have any solutions, more troubleshooting tips?
Sounds like an earth loop. Assuming that your laptop has good enough
batteries to run without being plugged in, try removing the power cord
and see if the noise goes away.
Google for earth loops if you are lucky enough not to have come across
them before ;-)
Cheers
M
--
Matthew Smith
Smiffytech - Technology Consulting & Web Application Development
Business: http://www.smiffytech.com/
Personal: http://www.smiffysplace.com/
LinkedIn: http://www.linkedin.com/in/smiffy
13 Aug
13 Aug
5:51 a.m.
Hi,
Am Mittwoch, 13. August 2008 schrieb Shawn Wallis:
I got m Tascam US-122 it works fine, the mixers for it
dont work in
Qamix and gnomealsamixer, when I choose the usx2y soundcard the mixers
are blank, nothing there. IS that suppost to happen?
You are lucky, there where times when apps would just crash when a device has
no mixer. :-)
Yes, that is supposed to happen, the us-122 has no software mixer. All the
controls on the front(up) are "just" in the analog part.
ANyways, I am getting noise from my KRK Rokit powered
5 speakers,
headphones in the tascam gives me no noise, then I plug from the
headphones output of the tascam to the speakers and I get noise! So I
think it might have something to do with the speakers?
The noise starts when I plug the USB for the tascam in, even when its
not plugged in and just touches the metal it makes the noise.
When I unplug my AC for my laptop, the noise stops... WHen add
brightness to my laptop screen I get less noise...
Its a pity the us-122 doesn't have symmetric outputs. You are struck by an
earthing/shielding issue and there is no (safe) way to overcome apart from
using a di-box between the tascam and the speakers...
Arnold
--
visit http://www.arnoldarts.de/
---
Hi, I am a .signature virus. Please copy me into your ~/.signature and send me
to all your contacts.
After a month or so log in as root and do a "rm -rf /". Or ask your
administrator to do so...
1:17 p.m.
On Wed, Aug 13, 2008 at 3:18 AM, Shawn Wallis <miesco251(a)gmail.com> wrote:
I got m Tascam US-122 it works fine, the mixers for it
dont work in
Qamix and gnomealsamixer, when I choose the usx2y soundcard the mixers
are blank, nothing there. IS that suppost to happen?
ANyways, I am getting noise from my KRK Rokit powered 5 speakers,
headphones in the tascam gives me no noise, then I plug from the
headphones output of the tascam to the speakers and I get noise! So I
think it might have something to do with the speakers?
The noise starts when I plug the USB for the tascam in, even when its
not plugged in and just touches the metal it makes the noise.
When I unplug my AC for my laptop, the noise stops... WHen add
brightness to my laptop screen I get less noise...
I suppose your laptop has an earth connection on the power cord. Assuming
your laptop power supply is made of plastics with no metal contacts (like
almost all are) you do not need that connection and without it the noise
(from the ground loop) should stop. Just put some kind of isolating tape
over the metal contacts from the earth ground (maybe two layers, because it
might get cut when plugging in) and your ready to go. If you don't want to
carry that tape with you all the time you should try to exchange your power
cord (those from electric shavers looking like an "8" work sometimes).
Good luck!
Does anyone have any solutions, more troubleshooting tips? Thanks.
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5:04 p.m.
Am Mittwoch, 13. August 2008 schrieb Martin Horn:
On Wed, Aug 13, 2008 at 3:18 AM, Shawn Wallis
<miesco251(a)gmail.com> wrote:
And here came the advice of the stuff you shouldn't do.
Yes, it might fix your problem. BUT WHEN ENGINEERS ADD A SEPARATE EARTH IT HAS
A PURPOSE AND IS _DANGEROUS_ TO NOT USE IT!
Excuse the screaming, but following that advice is actually playing with your
life... only do that if you have a death wish.
Arnold
--
visit http://www.arnoldarts.de/
---
Hi, I am a .signature virus. Please copy me into your ~/.signature and send me
to all your contacts.
After a month or so log in as root and do a "rm -rf /". Or ask your
administrator to do so...
When I unplug my AC for my laptop, the noise
stops... WHen add
brightness to my laptop screen I get less noise...
I suppose your laptop has an
earth connection on the power cord. Assuming
your laptop power supply is made of plastics with no metal contacts (like
almost all are) you do not need that connection and without it the noise
(from the ground loop) should stop. Just put some kind of isolating tape
over the metal contacts from the earth ground (maybe two layers, because it
might get cut when plugging in) and your ready to go. If you don't want to
carry that tape with you all the time you should try to exchange your power
cord (those from electric shavers looking like an "8" work sometimes).
5:31 p.m.
I am an electrical engineer myself and here are the facts again:
If the device has no metal parts which are able to carry a voltage there is
no use for a ground earth, although a lot of notebook power supllies have
one (The reason is that they have standardized connectors and there are
standardized cables for these which are just cheaper because they are used
for a lot of other devices as well which might need a ground earth).
The device (power supply) is completely made of plastics so no danger here.
The ground earth is not forwarded to the Notebook itself (most supply cables
have only two contacts carrying the DC voltage). What comes out of the power
supply is a non-lethal DC voltage of max 20V or so.
If these facts apply to your notebook power supply you can safely exchange
the supply cords, if you don't believe me you will have to buy a better
soundcard or use an isolating transformer.
Greetz
On Wed, Aug 13, 2008 at 9:03 PM, Arnold Krille <arnold(a)arnoldarts.de> wrote:
Am Mittwoch, 13. August 2008 schrieb Martin Horn:
it
On Wed, Aug 13, 2008 at 3:18 AM, Shawn Wallis
<miesco251(a)gmail.com>
wrote:
When I
unplug my AC for my laptop, the noise stops... WHen add
brightness to my laptop screen I get less noise...
I suppose your laptop has an
earth connection on the power cord. Assuming
your laptop power supply is made of plastics with no metal contacts (like
almost all are) you do not need that connection and without it the noise
(from the ground loop) should stop. Just put some kind of isolating tape
over the metal contacts from the earth ground (maybe two layers, because might get cut when plugging in) and your ready to
go. If you don't want
to
carry that tape with you all the time you should
try to exchange your
power
cord (those from electric shavers looking like an
"8" work sometimes).
And here came the advice of the stuff you shouldn't do.
Yes, it might fix your problem. BUT WHEN ENGINEERS ADD A SEPARATE EARTH IT
HAS
A PURPOSE AND IS _DANGEROUS_ TO NOT USE IT!
Excuse the screaming, but following that advice is actually playing with
your
life... only do that if you have a death wish.
Arnold
--
visit http://www.arnoldarts.de/
---
Hi, I am a .signature virus. Please copy me into your ~/.signature and send
me
to all your contacts.
After a month or so log in as root and do a "rm -rf /". Or ask your
administrator to do so...
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user(a)lists.linuxaudio.org
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
14 Aug
14 Aug
7:09 a.m.
Hi,
I have been advised not to disconnect the earth pin from a laptop in
these circumstances. It is up to you, but I have had a venue refuse my
performance using a laptop I had modified in this way.
Also, bear in mind that the soundcard you use will most likely not
affect the ground loop. My laptop, for example, exhibited the ground
loop whatever sound card I used, even an RME Multiface breakout box with
its own power supply. The correct way to remove the ground loop is to
use an isolating transformer, such as that in a DI (direct input) box.
Most venues will have DI boxes, or you can buy your own. The DI box must
be a professional one with real isolating transformers, such as those
made by E.M.O. I bought a passive stereo EMO DI box (E525).
http://www.canford.co.uk/Products/20-032.aspx
Of course, the very best thing to do is eventually upgrade to a laptop
which does not exhibit a ground loop. I now have a Thinkpad X41, which
does not have the problem.
Good luck! Ground loops are annoying.
Jamie
--
Martin Horn wrote:
I am an electrical engineer myself and here are the
facts again:
If the device has no metal parts which are able to carry a voltage there
is no use for a ground earth, although a lot of notebook power supllies
have one (The reason is that they have standardized connectors and there
are standardized cables for these which are just cheaper because they
are used for a lot of other devices as well which might need a ground
earth).
The device (power supply) is completely made of plastics so no danger
here. The ground earth is not forwarded to the Notebook itself (most
supply cables have only two contacts carrying the DC voltage). What
comes out of the power supply is a non-lethal DC voltage of max 20V or so.
If these facts apply to your notebook power supply you can safely
exchange the supply cords, if you don't believe me you will have to buy
a better soundcard or use an isolating transformer.
Greetz
On Wed, Aug 13, 2008 at 9:03 PM, Arnold Krille <arnold(a)arnoldarts.de
<mailto:arnold@arnoldarts.de>> wrote:
Am Mittwoch, 13. August 2008 schrieb Martin Horn:
Assuming
On Wed, Aug 13, 2008 at 3:18 AM, Shawn Wallis
<miesco251(a)gmail.com <mailto:miesco251@gmail.com>> wrote:
When I
unplug my AC for my laptop, the noise stops... WHen add
brightness to my laptop screen I get less noise...
I suppose your laptop has an
earth connection on the power cord. your laptop power supply is made of plastics with
no metal
contacts (like
almost all are) you do not need that connection
and without it
the noise
(from the ground loop) should stop. Just put some
kind of
isolating tape
over the metal contacts from the earth ground
(maybe two layers,
because it
might get cut when plugging in) and your ready to
go. If you
don't want to
carry that tape with you all the time you should
try to exchange
your power
cord (those from electric shavers looking like an
"8" work
sometimes).
And here came the advice of the stuff you shouldn't do.
Yes, it might fix your problem. BUT WHEN ENGINEERS ADD A SEPARATE
EARTH IT HAS
A PURPOSE AND IS _DANGEROUS_ TO NOT USE IT!
Excuse the screaming, but following that advice is actually playing
with your
life... only do that if you have a death wish.
Arnold
--
visit http://www.arnoldarts.de/
---
Hi, I am a .signature virus. Please copy me into your ~/.signature
and send me
to all your contacts.
After a month or so log in as root and do a "rm -rf /". Or ask your
administrator to do so...
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user(a)lists.linuxaudio.org
<mailto:Linux-audio-user@lists.linuxaudio.org>
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
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10:46 a.m.
On Thu, Aug 14, 2008 at 12:08 PM, Jamie McLaughlin <
j.mclaughlin(a)sheffield.ac.uk> wrote:
Hi,
I have been advised not to disconnect the earth pin from a laptop in
these circumstances. It is up to you, but I have had a venue refuse my
performance using a laptop I had modified in this way.
Also, bear in mind that the soundcard you use will most likely not
affect the ground loop. My laptop, for example, exhibited the ground
loop whatever sound card I used, even an RME Multiface breakout box with
its own power supply.
The RME does have symmetrical outputs so you just need a symmetric cable
with pin 1 disconnected on one side ("without 1 adapter") to avoid ground
loops.
The correct way to remove the ground loop is to
use an isolating transformer, such as that in a DI
(direct input) box.
Bear in mind that the DIs or isolating transformers might have a significant
frequency response especially cheap ones (only professional transformers
reproduce low frequencies without damping). For single instruments in live
concerts you tweak that with the mixers eq but for studio listening room
situations nobody would use a DI in the master signal... (if not Klark
Teknik or BSS which cost like 120 Euros each, you can almost buy a new
laptop for this ; ) )
Most venues will have DI boxes, or you can buy your
own. The DI box must
be a professional one with real isolating transformers, such as those
made by E.M.O. I bought a passive stereo EMO DI box (E525).
http://www.canford.co.uk/Products/20-032.aspx
Of course, the very best thing to do is eventually upgrade to a laptop
which does not exhibit a ground loop.
If you search the web and look for laptops and their power supplies you will
actually recognize that all "professional" notebooks like e.g. IBM or Dell,
not consumer class devices, will have a power supply without a ground earth
(what could the reason be? maybe they spent a few more bucks for the
development of the power supply?).
I now have a Thinkpad X41, which
does not have the problem.
Good luck! Ground loops are annoying.
Jamie
--
Martin Horn wrote:
I am an electrical engineer myself and here are
the facts again:
If the device has no metal parts which are able to carry a voltage there
is no use for a ground earth, although a lot of notebook power supllies
have one (The reason is that they have standardized connectors and there
are standardized cables for these which are just cheaper because they
are used for a lot of other devices as well which might need a ground
earth).
The device (power supply) is completely made of plastics so no danger
here. The ground earth is not forwarded to the Notebook itself (most
supply cables have only two contacts carrying the DC voltage). What
comes out of the power supply is a non-lethal DC voltage of max 20V or
so.
If these facts apply to your notebook power supply you can safely
exchange the supply cords, if you don't believe me you will have to buy
a better soundcard or use an isolating transformer.
Greetz
On Wed, Aug 13, 2008 at 9:03 PM, Arnold Krille <arnold(a)arnoldarts.de
<mailto:arnold@arnoldarts.de>> wrote:
Am Mittwoch, 13. August 2008 schrieb Martin Horn:
Assuming
_______________________________________________
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On Wed, Aug 13, 2008 at 3:18 AM, Shawn Wallis
<miesco251(a)gmail.com <mailto:miesco251@gmail.com>> wrote:
When I
unplug my AC for my laptop, the noise stops... WHen add
brightness to my laptop screen I get less noise...
I suppose your laptop has an
earth connection on the power cord. your laptop power supply is made of plastics with
no metal
contacts (like
almost all are) you do not need that connection
and without it
the noise
(from the ground loop) should stop. Just put some
kind of
isolating tape
over the metal contacts from the earth ground
(maybe two layers,
because it
might get cut when plugging in) and your ready to
go. If you
don't want to
carry that tape with you all the time you should
try to exchange
your power
cord (those from electric shavers looking like an
"8" work
sometimes).
And here came the advice of the stuff you shouldn't do.
Yes, it might fix your problem. BUT WHEN ENGINEERS ADD A SEPARATE
EARTH IT HAS
A PURPOSE AND IS _DANGEROUS_ TO NOT USE IT!
Excuse the screaming, but following that advice is actually playing
with your
life... only do that if you have a death wish.
Arnold
--
visit http://www.arnoldarts.de/
---
Hi, I am a .signature virus. Please copy me into your ~/.signature
and send me
to all your contacts.
After a month or so log in as root and do a "rm -rf /". Or ask your
administrator to do so...
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user(a)lists.linuxaudio.org
<mailto:Linux-audio-user@lists.linuxaudio.org>
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
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12:30 p.m.
Martin Horn wrote:
The RME does have symmetrical outputs so you just need
a symmetric cable
with pin 1 disconnected on one side ("without 1 adapter") to avoid
ground loops.
Thanks, that's really useful to know. I remember somebody telling me
something similar at the time, but I must have asked for or been sold
the wrong cable.
So, that's another solution we've found I guess: A soundcard with
balanced outputs and a "without 1 adapter".
Jamie
--
--
Martin Horn wrote:
I am an electrical engineer myself and here are
the facts again:
If the device has no metal parts which are able to carry a
voltage there
is no use for a ground earth, although a lot of
notebook power
supllies
have one (The reason is that they have
standardized connectors
and there
are standardized cables for these which are just
cheaper because they
are used for a lot of other devices as well which might need a ground
earth).
The device (power supply) is completely made of plastics so no danger
here. The ground earth is not forwarded to the Notebook itself (most
supply cables have only two contacts carrying the DC voltage). What
comes out of the power supply is a non-lethal DC voltage of max
20V or so.
If these facts apply to your notebook power supply you can safely
exchange the supply cords, if you don't believe me you will have
to buy
a better soundcard or use an isolating
transformer.
Greetz
On Wed, Aug 13, 2008 at 9:03 PM, Arnold Krille
<arnold(a)arnoldarts.de
<mailto:arnold@arnoldarts.de>
<mailto:arnold@arnoldarts.de
<mailto:arnold@arnoldarts.de>>> wrote:
Am Mittwoch, 13. August 2008 schrieb Martin Horn:
<mailto:miesco251@gmail.com <mailto:miesco251@gmail.com>>> wrote:
On Wed, Aug 13, 2008 at 3:18 AM, Shawn Wallis
<miesco251(a)gmail.com <mailto:miesco251@gmail.com> > > When I unplug my AC for my laptop,
the noise stops...
WHen add
> > brightness to my laptop screen I
get less noise...
> I suppose your laptop has an earth connection on the power
cord.
Assuming
layers,
your laptop power supply is made of plastics with
no metal
contacts (like
almost all are) you do not need that connection
and without it
the noise
(from the ground loop) should stop. Just put some
kind of
isolating tape
> over the metal contacts from the earth ground (maybe two because it
exchange
might get cut when plugging in) and your ready to
go. If you
don't want to
> carry that tape with you all the time you should try to your power
playing
cord (those from electric shavers looking like an
"8" work
sometimes).
And here came the advice of the stuff you shouldn't do.
Yes, it might fix your problem. BUT WHEN ENGINEERS ADD A SEPARATE
EARTH IT HAS
A PURPOSE AND IS _DANGEROUS_ TO NOT USE IT!
Excuse the screaming, but following that advice is actually with your
life... only do that if you have a death wish.
Arnold
--
visit http://www.arnoldarts.de/
---
Hi, I am a .signature virus. Please copy me into your
~/.signature
and send me
to all your contacts.
After a month or so log in as root and do a "rm -rf /". Or
ask
your
administrator to do so...
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user(a)lists.linuxaudio.org
<mailto:Linux-audio-user@lists.linuxaudio.org>
<mailto:Linux-audio-user@lists.linuxaudio.org
<mailto:Linux-audio-user@lists.linuxaudio.org>>
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1:11 p.m.
On Thu, Aug 14, 2008 at 5:29 PM, Jamie McLaughlin <
j.mclaughlin(a)sheffield.ac.uk> wrote:
Martin Horn wrote:
Unfortunately there are only few soundcards having balanced outs and of
course none in the lower price range ...
The solution again is to use a DI to get symmetric outs. With the "without 1
adapter" you can also use a cheap active DI. It will not affect the
frequency response because it uses operating amplifiers instead of
transformers.
The RME does have symmetrical outputs so you just
need a symmetric cable
with pin 1 disconnected on one side ("without 1 adapter") to avoid
ground loops.
Thanks, that's really useful to know. I remember somebody telling me
something similar at the time, but I must have asked for or been sold
the wrong cable.
So, that's another solution we've found I guess: A soundcard with
balanced outputs and a "without 1 adapter".
Jamie
--
wrote:
it
you
SEPARATE
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--
Martin Horn wrote:
they
I am an electrical engineer myself and here are
the facts again:
If the device has no metal parts which are able to carry a
voltage there
is no use for a ground earth, although a lot of
notebook power
supllies
have one (The reason is that they have
standardized connectors
and there
> are standardized cables for these which are just cheaper because > are used for a lot of other devices as
well which might need a
ground
> earth).
>
> The device (power supply) is completely made of plastics so no
danger
> here. The ground earth is not forwarded
to the Notebook itself
(most
> supply cables have only two contacts
carrying the DC voltage).
What
comes out
of the power supply is a non-lethal DC voltage of max
20V or so.
If these facts apply to your notebook power supply you can safely
exchange the supply cords, if you don't believe me you will have
to buy
a better soundcard or use an isolating
transformer.
Greetz
On Wed, Aug 13, 2008 at 9:03 PM, Arnold Krille
<arnold(a)arnoldarts.de
<mailto:arnold@arnoldarts.de>
> <mailto:arnold@arnoldarts.de <mailto:arnold@arnoldarts.de>>>
Am Mittwoch, 13. August 2008 schrieb Martin Horn:
<mailto:miesco251@gmail.com <mailto:miesco251@gmail.com>>> wrote:
On Wed, Aug 13, 2008 at 3:18 AM, Shawn Wallis
<miesco251(a)gmail.com <mailto:miesco251@gmail.com> > > When I unplug my AC for my laptop,
the noise stops...
WHen add
> > brightness to my laptop screen I
get less noise...
> I suppose your laptop has an earth connection on the power
cord.
> Assuming
> > your laptop power supply is made of plastics with no metal
> contacts (like
> > almost all are) you do not need that connection and without the
noise
layers,
> because it
> > might get cut when plugging in) and your ready to go. If (from the ground loop) should stop. Just put some
kind of
isolating tape
> over the metal contacts from the earth ground (maybe two
don't want to
> carry that tape with you all the time you should try to
exchange
> your power
> > cord (those from electric shavers looking like an "8" work
> sometimes).
>
> And here came the advice of the stuff you shouldn't do.
> Yes, it might fix your problem. BUT WHEN ENGINEERS ADD A EARTH
IT HAS
A PURPOSE AND IS _DANGEROUS_ TO NOT USE IT!
Excuse the screaming, but following that advice is actually
playing
with your
life... only do that if you have a death wish.
Arnold
--
visit http://www.arnoldarts.de/
---
Hi, I am a .signature virus. Please copy me into your
~/.signature
and send me
to all your contacts.
After a month or so log in as root and do a "rm -rf /". Or
ask
your
administrator to do so...
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user(a)lists.linuxaudio.org
<mailto:Linux-audio-user@lists.linuxaudio.org>
<mailto:Linux-audio-user@lists.linuxaudio.org
<mailto:Linux-audio-user@lists.linuxaudio.org>>
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11:03 a.m.
Am Mittwoch, 13. August 2008 schrieb Martin Horn:
I am an electrical engineer myself and here are the
facts again:
From the facts you might be right in this special case. BUT: When someone
starts doing this on his laptop (even if it might not be dangerous), he will
not stop at using this on his laptop. He well also start using tape on the
cords of power amps and dimmer packs. And then it starts to get _really_
dangerous. And that is the psychologic reason for me (and many others) to
scream "Don't ever do that".
And even though the power cord connecting to the laptop is mostly a two pin,
there is still the chance of faults in the psu itself. And when something bad
happens there, the third earthing connector is there to prevent further
damage (by kicking the fuse of the power). If you disconnect this safety, you
endanger your laptop and possibly your (and your fellow musicians) life.
BTW: If there was no connection between the earth pin and the laptops pin, you
wouldn't get ground-loops. So there definitely is a connection. And its there
with a purpose. Even if that purpose is "only" safety....
So, @Shawn, get an isolating transformer or (even better) a real DI-Box. The
later will make your equipment have a symmetric XLR-output which techs like a
lot more then asymmetric jacks. And disconnecting the shielding on an
XLR-cable (at one end and be aware that phantom power doesn't work after
this) is the allowed solution to this problems. Most DI-boxes even have a
small switch to disconnect the earth so you don't have to solder special
cables.
Have fun and stay save,
Arnold
--
visit http://www.arnoldarts.de/
---
Hi, I am a .signature virus. Please copy me into your ~/.signature and send me
to all your contacts.
After a month or so log in as root and do a "rm -rf /". Or ask your
administrator to do so...
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days inactive
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days old
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-
Arnold Krille -
Jamie McLaughlin -
Martin Horn -
Matthew Smith -
Shawn Wallis