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me
 
Posts: n/a
Default Can you explain this 50Hz hum??

This is so annoying. The only thing I have on are the computer and mixer
(and hence the power transformer I use here in Germany for my US gear). The
mixer's first two channel inserts are connected to delta1010 ins1/2. There
are two mics coming into those channels, but even with the mic cables
unplugged and trim all the way down, the delta monitor shows the following:
www.guitar-dreams.com/misc/delta1010problem1.jpg

If I unplug the inserts it goes away. The recorded audio is

http://www.guitar-dreams.com/misc/de...0waveform1.mp3

The spectrum analysis shows

http://www.guitar-dreams.com/misc/de...0waveform1.jpg

So, if I take the unplugged insert and touch it against any jack on the
mixer, the input level on the delta then rises back to the level shown in
the picture above (first one). I then touched it against one of the screws
that is holding the delta on my rack and suddenly both delta ins 1/2 input
levels dropped down. Not completely though.

There is still a waveform there

http://www.guitar-dreams.com/misc/de...0waveform2.mp3

with a similar specal analysis

http://www.guitar-dreams.com/misc/de...0waveform2.jpg

Any idea what is going on here? In both cases, the spectral peaks are at
50Hz which of course is no coincidence. I would be tempted to think it has
something to do with the step down transformer I am using on my US gear. But
in this apartment, if I turn on a stereo, I hear 50Hz coming through the
speakers regardless of the transformer.

I feel like I am just doomed in this apartment. I hear 50Hz everywhere. The
fridge, etc,etc.



  #2   Report Post  
Chris Hornbeck
 
Posts: n/a
Default Can you explain this 50Hz hum??

On Mon, 27 Oct 2003 20:36:49 GMT, "me" wrote:

This is so annoying. The only thing I have on are the computer and mixer


This sounds like a classic case of ground loop. First
read the FAQ, then check back. BTW, it's called a loop
because the ground path is one turn of a big transformer.
If you break that path, no current can flow; hence, no hum.

Good fortune,

Chris Hornbeck
new email address
  #3   Report Post  
Chris Hornbeck
 
Posts: n/a
Default Can you explain this 50Hz hum??

On Mon, 27 Oct 2003 20:36:49 GMT, "me" wrote:

This is so annoying. The only thing I have on are the computer and mixer


This sounds like a classic case of ground loop. First
read the FAQ, then check back. BTW, it's called a loop
because the ground path is one turn of a big transformer.
If you break that path, no current can flow; hence, no hum.

Good fortune,

Chris Hornbeck
new email address
  #4   Report Post  
me
 
Posts: n/a
Default Can you explain this 50Hz hum??

I know about ground loops when it comes to driving 2 amps with one guitar,
and I know how that problem is solved. I feel this is different. I have
never dealt with a problem that involves the computer.

-brian

"Chris Hornbeck" wrote in message
...
On Mon, 27 Oct 2003 20:36:49 GMT, "me" wrote:

This is so annoying. The only thing I have on are the computer and mixer


This sounds like a classic case of ground loop. First
read the FAQ, then check back. BTW, it's called a loop
because the ground path is one turn of a big transformer.
If you break that path, no current can flow; hence, no hum.

Good fortune,

Chris Hornbeck
new email address



  #5   Report Post  
me
 
Posts: n/a
Default Can you explain this 50Hz hum??

I know about ground loops when it comes to driving 2 amps with one guitar,
and I know how that problem is solved. I feel this is different. I have
never dealt with a problem that involves the computer.

-brian

"Chris Hornbeck" wrote in message
...
On Mon, 27 Oct 2003 20:36:49 GMT, "me" wrote:

This is so annoying. The only thing I have on are the computer and mixer


This sounds like a classic case of ground loop. First
read the FAQ, then check back. BTW, it's called a loop
because the ground path is one turn of a big transformer.
If you break that path, no current can flow; hence, no hum.

Good fortune,

Chris Hornbeck
new email address





  #6   Report Post  
Mike Dobony
 
Posts: n/a
Default Can you explain this 50Hz hum??


"me" wrote in message
s.com...
I know about ground loops when it comes to driving 2 amps with one guitar,
and I know how that problem is solved. I feel this is different. I have
never dealt with a problem that involves the computer.

-brian


It is no different with a computer. However, you mentioned it is associated
with an insert. I had the same problem and it was the cable. Try a new
cable.
--
Mike D.

www.stopassaultnow.org

Remove .spamnot to respond by email



"Chris Hornbeck" wrote in

message
...
On Mon, 27 Oct 2003 20:36:49 GMT, "me" wrote:

This is so annoying. The only thing I have on are the computer and

mixer

This sounds like a classic case of ground loop. First
read the FAQ, then check back. BTW, it's called a loop
because the ground path is one turn of a big transformer.
If you break that path, no current can flow; hence, no hum.

Good fortune,

Chris Hornbeck
new email address





---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.532 / Virus Database: 326 - Release Date: 10/27/2003


  #7   Report Post  
Mike Dobony
 
Posts: n/a
Default Can you explain this 50Hz hum??


"me" wrote in message
s.com...
I know about ground loops when it comes to driving 2 amps with one guitar,
and I know how that problem is solved. I feel this is different. I have
never dealt with a problem that involves the computer.

-brian


It is no different with a computer. However, you mentioned it is associated
with an insert. I had the same problem and it was the cable. Try a new
cable.
--
Mike D.

www.stopassaultnow.org

Remove .spamnot to respond by email



"Chris Hornbeck" wrote in

message
...
On Mon, 27 Oct 2003 20:36:49 GMT, "me" wrote:

This is so annoying. The only thing I have on are the computer and

mixer

This sounds like a classic case of ground loop. First
read the FAQ, then check back. BTW, it's called a loop
because the ground path is one turn of a big transformer.
If you break that path, no current can flow; hence, no hum.

Good fortune,

Chris Hornbeck
new email address





---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.532 / Virus Database: 326 - Release Date: 10/27/2003


  #8   Report Post  
Walter Chan
 
Posts: n/a
Default Can you explain this 50Hz hum??

Invert the phase.

"me" wrote in message
s.com...
This is so annoying. The only thing I have on are the computer and mixer
(and hence the power transformer I use here in Germany for my US gear).

The
mixer's first two channel inserts are connected to delta1010 ins1/2. There
are two mics coming into those channels, but even with the mic cables
unplugged and trim all the way down, the delta monitor shows the

following:
www.guitar-dreams.com/misc/delta1010problem1.jpg

If I unplug the inserts it goes away. The recorded audio is

http://www.guitar-dreams.com/misc/de...0waveform1.mp3

The spectrum analysis shows

http://www.guitar-dreams.com/misc/de...0waveform1.jpg

So, if I take the unplugged insert and touch it against any jack on the
mixer, the input level on the delta then rises back to the level shown in
the picture above (first one). I then touched it against one of the screws
that is holding the delta on my rack and suddenly both delta ins 1/2 input
levels dropped down. Not completely though.

There is still a waveform there

http://www.guitar-dreams.com/misc/de...0waveform2.mp3

with a similar specal analysis

http://www.guitar-dreams.com/misc/de...0waveform2.jpg

Any idea what is going on here? In both cases, the spectral peaks are at
50Hz which of course is no coincidence. I would be tempted to think it has
something to do with the step down transformer I am using on my US gear.

But
in this apartment, if I turn on a stereo, I hear 50Hz coming through the
speakers regardless of the transformer.

I feel like I am just doomed in this apartment. I hear 50Hz everywhere.

The
fridge, etc,etc.





  #9   Report Post  
Walter Chan
 
Posts: n/a
Default Can you explain this 50Hz hum??

Invert the phase.

"me" wrote in message
s.com...
This is so annoying. The only thing I have on are the computer and mixer
(and hence the power transformer I use here in Germany for my US gear).

The
mixer's first two channel inserts are connected to delta1010 ins1/2. There
are two mics coming into those channels, but even with the mic cables
unplugged and trim all the way down, the delta monitor shows the

following:
www.guitar-dreams.com/misc/delta1010problem1.jpg

If I unplug the inserts it goes away. The recorded audio is

http://www.guitar-dreams.com/misc/de...0waveform1.mp3

The spectrum analysis shows

http://www.guitar-dreams.com/misc/de...0waveform1.jpg

So, if I take the unplugged insert and touch it against any jack on the
mixer, the input level on the delta then rises back to the level shown in
the picture above (first one). I then touched it against one of the screws
that is holding the delta on my rack and suddenly both delta ins 1/2 input
levels dropped down. Not completely though.

There is still a waveform there

http://www.guitar-dreams.com/misc/de...0waveform2.mp3

with a similar specal analysis

http://www.guitar-dreams.com/misc/de...0waveform2.jpg

Any idea what is going on here? In both cases, the spectral peaks are at
50Hz which of course is no coincidence. I would be tempted to think it has
something to do with the step down transformer I am using on my US gear.

But
in this apartment, if I turn on a stereo, I hear 50Hz coming through the
speakers regardless of the transformer.

I feel like I am just doomed in this apartment. I hear 50Hz everywhere.

The
fridge, etc,etc.





  #10   Report Post  
Don Cooper
 
Posts: n/a
Default Can you explain this 50Hz hum??



Mike Dobony wrote:

I had the same problem and it was the cable. Try a new cable.



We have the 60Hz hum here. It's "10 louder". But seriously, it does
sound like it's the cable, especially if there's stereo mini involved.


Don


  #11   Report Post  
Don Cooper
 
Posts: n/a
Default Can you explain this 50Hz hum??



Mike Dobony wrote:

I had the same problem and it was the cable. Try a new cable.



We have the 60Hz hum here. It's "10 louder". But seriously, it does
sound like it's the cable, especially if there's stereo mini involved.


Don
  #12   Report Post  
Brian Huether
 
Posts: n/a
Default Can you explain this 50Hz hum??

It happens with a variety of cables.

-brian

"Mike Dobony" wrote in message
...

"me" wrote in message
s.com...
I know about ground loops when it comes to driving 2 amps with one

guitar,
and I know how that problem is solved. I feel this is different. I have
never dealt with a problem that involves the computer.

-brian


It is no different with a computer. However, you mentioned it is

associated
with an insert. I had the same problem and it was the cable. Try a new
cable.
--
Mike D.

www.stopassaultnow.org

Remove .spamnot to respond by email



"Chris Hornbeck" wrote in

message
...
On Mon, 27 Oct 2003 20:36:49 GMT, "me" wrote:

This is so annoying. The only thing I have on are the computer and

mixer

This sounds like a classic case of ground loop. First
read the FAQ, then check back. BTW, it's called a loop
because the ground path is one turn of a big transformer.
If you break that path, no current can flow; hence, no hum.

Good fortune,

Chris Hornbeck
new email address





---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.532 / Virus Database: 326 - Release Date: 10/27/2003




  #13   Report Post  
Brian Huether
 
Posts: n/a
Default Can you explain this 50Hz hum??

Invert the phase of what?

-brian

"Walter Chan" wrote in message
...
Invert the phase.

"me" wrote in message
s.com...
This is so annoying. The only thing I have on are the computer and mixer
(and hence the power transformer I use here in Germany for my US gear).

The
mixer's first two channel inserts are connected to delta1010 ins1/2.

There
are two mics coming into those channels, but even with the mic cables
unplugged and trim all the way down, the delta monitor shows the

following:
www.guitar-dreams.com/misc/delta1010problem1.jpg

If I unplug the inserts it goes away. The recorded audio is

http://www.guitar-dreams.com/misc/de...0waveform1.mp3

The spectrum analysis shows

http://www.guitar-dreams.com/misc/de...0waveform1.jpg

So, if I take the unplugged insert and touch it against any jack on the
mixer, the input level on the delta then rises back to the level shown

in
the picture above (first one). I then touched it against one of the

screws
that is holding the delta on my rack and suddenly both delta ins 1/2

input
levels dropped down. Not completely though.

There is still a waveform there

http://www.guitar-dreams.com/misc/de...0waveform2.mp3

with a similar specal analysis

http://www.guitar-dreams.com/misc/de...0waveform2.jpg

Any idea what is going on here? In both cases, the spectral peaks are at
50Hz which of course is no coincidence. I would be tempted to think it

has
something to do with the step down transformer I am using on my US gear.

But
in this apartment, if I turn on a stereo, I hear 50Hz coming through the
speakers regardless of the transformer.

I feel like I am just doomed in this apartment. I hear 50Hz everywhere.

The
fridge, etc,etc.







  #14   Report Post  
Justin Ulysses Morse
 
Posts: n/a
Default Can you explain this 50Hz hum??

You have a grounding problem. The three types are "not enough ground,"
"too much ground," or "mislocated ground."

To see if you have "not enough ground," just connect a wire from the
chassis of the mixer to the chassis of the Delta1010. If that solves
the problem, then you can fix it "for real" by figuring out why you
weren't getting a solid ground connection in your audio cable.

To see if you have "too much ground," you need to disconnect a ground
wire someplace. The safest way to do this is to use an audio cable
with its shield cut at one end. It's not considered safe to lift the
ground on the power cable.

If neither of these is your problem, then you're in a tough spot
because you can't do much about the 3rd possibility.

My suspicion is that the equipment is expecting to see a solid ground
connection through the power cable, but that you have inadvertently
lifted that ground by using a 220:110 stepdown transformer that is
ungrounded.

ulysses


In article m, me
wrote:

This is so annoying. The only thing I have on are the computer and mixer
(and hence the power transformer I use here in Germany for my US gear). The
mixer's first two channel inserts are connected to delta1010 ins1/2. There
are two mics coming into those channels, but even with the mic cables
unplugged and trim all the way down, the delta monitor shows the following:
www.guitar-dreams.com/misc/delta1010problem1.jpg

If I unplug the inserts it goes away. The recorded audio is

http://www.guitar-dreams.com/misc/de...0waveform1.mp3

The spectrum analysis shows

http://www.guitar-dreams.com/misc/de...0waveform1.jpg

So, if I take the unplugged insert and touch it against any jack on the
mixer, the input level on the delta then rises back to the level shown in
the picture above (first one). I then touched it against one of the screws
that is holding the delta on my rack and suddenly both delta ins 1/2 input
levels dropped down. Not completely though.

There is still a waveform there

http://www.guitar-dreams.com/misc/de...0waveform2.mp3

with a similar specal analysis

http://www.guitar-dreams.com/misc/de...0waveform2.jpg

Any idea what is going on here? In both cases, the spectral peaks are at
50Hz which of course is no coincidence. I would be tempted to think it has
something to do with the step down transformer I am using on my US gear. But
in this apartment, if I turn on a stereo, I hear 50Hz coming through the
speakers regardless of the transformer.

I feel like I am just doomed in this apartment. I hear 50Hz everywhere. The
fridge, etc,etc.



  #15   Report Post  
Don Cooper
 
Posts: n/a
Default Can you explain this 50Hz hum??



Brian Huether wrote:

It happens with a variety of cables.



I wonder if there's a short in back of the panel, then.


Don


  #16   Report Post  
Rob Reedijk
 
Posts: n/a
Default Can you explain this 50Hz hum??

I don't know if you have looked into this, but is your computer connected
to the internet by cable or phone? Does the hum go away when you physically
disconnect?

rob R.

me wrote:
This is so annoying. The only thing I have on are the computer and mixer
(and hence the power transformer I use here in Germany for my US gear). The
mixer's first two channel inserts are connected to delta1010 ins1/2. There
are two mics coming into those channels, but even with the mic cables
unplugged and trim all the way down, the delta monitor shows the following:
www.guitar-dreams.com/misc/delta1010problem1.jpg


If I unplug the inserts it goes away. The recorded audio is


http://www.guitar-dreams.com/misc/de...0waveform1.mp3


The spectrum analysis shows


http://www.guitar-dreams.com/misc/de...0waveform1.jpg


So, if I take the unplugged insert and touch it against any jack on the
mixer, the input level on the delta then rises back to the level shown in
the picture above (first one). I then touched it against one of the screws
that is holding the delta on my rack and suddenly both delta ins 1/2 input
levels dropped down. Not completely though.


There is still a waveform there


http://www.guitar-dreams.com/misc/de...0waveform2.mp3


with a similar specal analysis


http://www.guitar-dreams.com/misc/de...0waveform2.jpg


Any idea what is going on here? In both cases, the spectral peaks are at
50Hz which of course is no coincidence. I would be tempted to think it has
something to do with the step down transformer I am using on my US gear. But
in this apartment, if I turn on a stereo, I hear 50Hz coming through the
speakers regardless of the transformer.


I feel like I am just doomed in this apartment. I hear 50Hz everywhere. The
fridge, etc,etc.



  #17   Report Post  
Joakim Wendel
 
Posts: n/a
Default Can you explain this 50Hz hum??

In article ,
Justin Ulysses Morse wrote:

You have a grounding problem. The three types are "not enough ground,"
"too much ground," or "mislocated ground."
SNIP

If neither of these is your problem, then you're in a tough spot
because you can't do much about the 3rd possibility.


I think that sometimes the Cable as in cable TV or Broadband connection
jack has it's ground elsewhere, try pulling that if you have one ...

--
Joakim Wendel
Remove obvious mail JUNK block for mail reply.

My homepage : http://violinist.nu
  #18   Report Post  
S O'Neill
 
Posts: n/a
Default Can you explain this 50Hz hum??

I don't know your step-down transformer, but could it be operating non-linearly
(perhaps saturating) and sending 50-Hz-modulated trash in through a power supply?

me wrote:

This is so annoying. The only thing I have on are the computer and mixer



  #19   Report Post  
Walter Chan
 
Posts: n/a
Default Can you explain this 50Hz hum??


"Brian Huether" wrote in message
...
Invert the phase of what?

-brian


In an unbalanced situation, the 'hot' and 'ground'. In a balanced situation
the 'hot' and 'cold'.

unbalanced: RCA.
balanced: XLR - swap pins 2 and 3
balanced: TRS - swap ring and tip.

Alternatively, ground any unused pins on a balanced connector (i.e. solder
pin 2 (or pin 3) to pin 1 on the XLR)

I'd do it with a separate adapter (always have them handy).












"Walter Chan" wrote in message
...
Invert the phase.

"me" wrote in message
s.com...
This is so annoying. The only thing I have on are the computer and

mixer
(and hence the power transformer I use here in Germany for my US

gear).
The
mixer's first two channel inserts are connected to delta1010 ins1/2.

There
are two mics coming into those channels, but even with the mic cables
unplugged and trim all the way down, the delta monitor shows the

following:
www.guitar-dreams.com/misc/delta1010problem1.jpg

If I unplug the inserts it goes away. The recorded audio is

http://www.guitar-dreams.com/misc/de...0waveform1.mp3

The spectrum analysis shows

http://www.guitar-dreams.com/misc/de...0waveform1.jpg

So, if I take the unplugged insert and touch it against any jack on

the
mixer, the input level on the delta then rises back to the level shown

in
the picture above (first one). I then touched it against one of the

screws
that is holding the delta on my rack and suddenly both delta ins 1/2

input
levels dropped down. Not completely though.

There is still a waveform there

http://www.guitar-dreams.com/misc/de...0waveform2.mp3

with a similar specal analysis

http://www.guitar-dreams.com/misc/de...0waveform2.jpg

Any idea what is going on here? In both cases, the spectral peaks are

at
50Hz which of course is no coincidence. I would be tempted to think it

has
something to do with the step down transformer I am using on my US

gear.
But
in this apartment, if I turn on a stereo, I hear 50Hz coming through

the
speakers regardless of the transformer.

I feel like I am just doomed in this apartment. I hear 50Hz

everywhere.
The
fridge, etc,etc.









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