I have read posts on this subject, but seen no real solutions:

I moved from USA to Germany two years ago. I brought along some audio
gear. I found a 500w transformer on ebay.de that gives me roughly 120v
and runs everything pretty much without a hitch, except for my Proton
D940 Receiver. When I first plugged it in, everything was fine. But
after awhile a 50 hz hum started coming from the speakers. At first I
experimented with reversing the power plugs of both the transformer
and the receiver. I was able to make it go away, but it always came
back. Now any changes in wiring don't produce audible effect. What I
find interesting is that what I am getting is a low level 50hz hum in
the speakers that is independant of the volume control, so it is not a
problem when I am cranking, only when I want to work at the computer
late at night, like now. Also, this hum seems to not affect preamp
circuits, as I can transfer audio from vinyl to digital without
picking up the hum, for example.

The transformer itself is audible even without load. That probably
points a finger, but I am wondering if this a problem without a
solution. I have often noticed audible hum in neighbors' stereo units.
Is 50 hz inherently harder to filter? Also, I brought a Hartke bass
amplifier which was dual voltage, 50/60. It works, but the unit itself
hums like mad. Interestingly, the hum does not come out of the
speakers significantly.

I do not know details of German house wiring and grounding
configurations, but it seems that it is single phase with one side
roughly 227v and the other neutral to ground. I measure no potential
between neutral, electrical ground, and earth ground (i.e. my steam
radiator).

I am running connected components some powered from the transformer
and others direct to the house voltage. This is probably a bad idea,
but no amount of fiddling seems to remove the hum from my speakers, or
add it anywhere else.

I suppose I could solve the problem by throwing enough money at a new
receiver or power amp, but I just like tinkering with problems,
solving them myself, and keeping my money. (Example: I drive a Saab
with 330,000km on it. It's still a great car!) Also, I like the
switching features on my Proton; separate listen and record out
selection, and pre-out and pwr-amp in jumpers. What new home theater
receiver has that?

Anyone know some details about hum, specifically in the 50hz range?

Robobass

In , on 06/22/04
at 04:28 PM, (robobass) said:

I have read posts on this subject, but seen no real solutions:

I moved from USA to Germany two years ago. I brought along some audio
gear. I found a 500w transformer on ebay.de that gives me roughly 120v
and runs everything pretty much without a hitch, except for my Proton
D940 Receiver. When I first plugged it in, everything was fine. But
after awhile a 50 hz hum started coming from the speakers. At first I
experimented with reversing the power plugs of both the transformer
and the receiver. I was able to make it go away, but it always came

I'm not sure there are any practical solutions.

It could be that the filtering in the amplifier is not quite up to
dealing with the 50Hz.

The transformer will run a bit warmer at 50 Hz and the heat may have
loosened some of the laminations that are now making more noise.

Since the unit will run warmer on 50Hz, the power supply filter
capacitors may have aged somewhat faster than normal.

Some power transformers are sensitive to the harmonic content of the
power line (which could vary by time of day). Some harmonics may cause
more audible mechanical hum.

That voltage reduction transformer may have an external magnetic field
that is inducing hum.

----

You could move things around to deal with an external field. Tightening
the power transformer lamination clamps may be possible and may help.
Dealing with a power line harmonic problem (if you have one) is messy.

My suggestion is to have the unit checked by a professional who has the
proper instrumentation (you may have to loan your step-down transformer
to the service station). If the unit is OK (other than having a tough
time with 50Hz), I think the most practical solution is to replace the
unit temporarily or permenantly as appropriate considering your current
expat status.

Note that a power line harmonic problem could be local to your area.
The harmonic may not be present at the service center.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 06/22/04
at 04:28 PM, (robobass) said:

I have read posts on this subject, but seen no real solutions:

I moved from USA to Germany two years ago. I brought along some audio
gear. I found a 500w transformer on ebay.de that gives me roughly 120v
and runs everything pretty much without a hitch, except for my Proton
D940 Receiver. When I first plugged it in, everything was fine. But
after awhile a 50 hz hum started coming from the speakers. At first I
experimented with reversing the power plugs of both the transformer
and the receiver. I was able to make it go away, but it always came

I'm not sure there are any practical solutions.

It could be that the filtering in the amplifier is not quite up to
dealing with the 50Hz.

The transformer will run a bit warmer at 50 Hz and the heat may have
loosened some of the laminations that are now making more noise.

Since the unit will run warmer on 50Hz, the power supply filter
capacitors may have aged somewhat faster than normal.

Some power transformers are sensitive to the harmonic content of the
power line (which could vary by time of day). Some harmonics may cause
more audible mechanical hum.

That voltage reduction transformer may have an external magnetic field
that is inducing hum.

----

You could move things around to deal with an external field. Tightening
the power transformer lamination clamps may be possible and may help.
Dealing with a power line harmonic problem (if you have one) is messy.

My suggestion is to have the unit checked by a professional who has the
proper instrumentation (you may have to loan your step-down transformer
to the service station). If the unit is OK (other than having a tough
time with 50Hz), I think the most practical solution is to replace the
unit temporarily or permenantly as appropriate considering your current
expat status.

Note that a power line harmonic problem could be local to your area.
The harmonic may not be present at the service center.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 06/22/04
at 04:28 PM, (robobass) said:

I have read posts on this subject, but seen no real solutions:

I moved from USA to Germany two years ago. I brought along some audio
gear. I found a 500w transformer on ebay.de that gives me roughly 120v
and runs everything pretty much without a hitch, except for my Proton
D940 Receiver. When I first plugged it in, everything was fine. But
after awhile a 50 hz hum started coming from the speakers. At first I
experimented with reversing the power plugs of both the transformer
and the receiver. I was able to make it go away, but it always came

I'm not sure there are any practical solutions.

It could be that the filtering in the amplifier is not quite up to
dealing with the 50Hz.

The transformer will run a bit warmer at 50 Hz and the heat may have
loosened some of the laminations that are now making more noise.

Since the unit will run warmer on 50Hz, the power supply filter
capacitors may have aged somewhat faster than normal.

Some power transformers are sensitive to the harmonic content of the
power line (which could vary by time of day). Some harmonics may cause
more audible mechanical hum.

That voltage reduction transformer may have an external magnetic field
that is inducing hum.

----

You could move things around to deal with an external field. Tightening
the power transformer lamination clamps may be possible and may help.
Dealing with a power line harmonic problem (if you have one) is messy.

My suggestion is to have the unit checked by a professional who has the
proper instrumentation (you may have to loan your step-down transformer
to the service station). If the unit is OK (other than having a tough
time with 50Hz), I think the most practical solution is to replace the
unit temporarily or permenantly as appropriate considering your current
expat status.

Note that a power line harmonic problem could be local to your area.
The harmonic may not be present at the service center.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

If you are getting the hum out of the speakers, and you do not have a
shielding problem from the interconnects, this means that the main filter
caps in the power supply have to be changed.

One test is to disconnect all the interconnects, and see if there is still
hum. If so, get the unit serviced.

The power transformer in the unit is most likely running hotter, because it
was probably designed to run on 60 Hz. It would not hurt to replace the main
filter caps with ones of a bit of a higher "uF" rating, if there is enough
physical space. An experienced technician should know what to do with this
problem.

--

Jerry G.
=====


"robobass" wrote in message
om...
I have read posts on this subject, but seen no real solutions:

I moved from USA to Germany two years ago. I brought along some audio
gear. I found a 500w transformer on ebay.de that gives me roughly 120v
and runs everything pretty much without a hitch, except for my Proton
D940 Receiver. When I first plugged it in, everything was fine. But
after awhile a 50 hz hum started coming from the speakers. At first I
experimented with reversing the power plugs of both the transformer
and the receiver. I was able to make it go away, but it always came
back. Now any changes in wiring don't produce audible effect. What I
find interesting is that what I am getting is a low level 50hz hum in
the speakers that is independant of the volume control, so it is not a
problem when I am cranking, only when I want to work at the computer
late at night, like now. Also, this hum seems to not affect preamp
circuits, as I can transfer audio from vinyl to digital without
picking up the hum, for example.

The transformer itself is audible even without load. That probably
points a finger, but I am wondering if this a problem without a
solution. I have often noticed audible hum in neighbors' stereo units.
Is 50 hz inherently harder to filter? Also, I brought a Hartke bass
amplifier which was dual voltage, 50/60. It works, but the unit itself
hums like mad. Interestingly, the hum does not come out of the
speakers significantly.

I do not know details of German house wiring and grounding
configurations, but it seems that it is single phase with one side
roughly 227v and the other neutral to ground. I measure no potential
between neutral, electrical ground, and earth ground (i.e. my steam
radiator).

I am running connected components some powered from the transformer
and others direct to the house voltage. This is probably a bad idea,
but no amount of fiddling seems to remove the hum from my speakers, or
add it anywhere else.

I suppose I could solve the problem by throwing enough money at a new
receiver or power amp, but I just like tinkering with problems,
solving them myself, and keeping my money. (Example: I drive a Saab
with 330,000km on it. It's still a great car!) Also, I like the
switching features on my Proton; separate listen and record out
selection, and pre-out and pwr-amp in jumpers. What new home theater
receiver has that?

Anyone know some details about hum, specifically in the 50hz range?

Robobass

If you are getting the hum out of the speakers, and you do not have a
shielding problem from the interconnects, this means that the main filter
caps in the power supply have to be changed.

One test is to disconnect all the interconnects, and see if there is still
hum. If so, get the unit serviced.

The power transformer in the unit is most likely running hotter, because it
was probably designed to run on 60 Hz. It would not hurt to replace the main
filter caps with ones of a bit of a higher "uF" rating, if there is enough
physical space. An experienced technician should know what to do with this
problem.

--

Jerry G.
=====


"robobass" wrote in message
om...
I have read posts on this subject, but seen no real solutions:

I moved from USA to Germany two years ago. I brought along some audio
gear. I found a 500w transformer on ebay.de that gives me roughly 120v
and runs everything pretty much without a hitch, except for my Proton
D940 Receiver. When I first plugged it in, everything was fine. But
after awhile a 50 hz hum started coming from the speakers. At first I
experimented with reversing the power plugs of both the transformer
and the receiver. I was able to make it go away, but it always came
back. Now any changes in wiring don't produce audible effect. What I
find interesting is that what I am getting is a low level 50hz hum in
the speakers that is independant of the volume control, so it is not a
problem when I am cranking, only when I want to work at the computer
late at night, like now. Also, this hum seems to not affect preamp
circuits, as I can transfer audio from vinyl to digital without
picking up the hum, for example.

The transformer itself is audible even without load. That probably
points a finger, but I am wondering if this a problem without a
solution. I have often noticed audible hum in neighbors' stereo units.
Is 50 hz inherently harder to filter? Also, I brought a Hartke bass
amplifier which was dual voltage, 50/60. It works, but the unit itself
hums like mad. Interestingly, the hum does not come out of the
speakers significantly.

I do not know details of German house wiring and grounding
configurations, but it seems that it is single phase with one side
roughly 227v and the other neutral to ground. I measure no potential
between neutral, electrical ground, and earth ground (i.e. my steam
radiator).

I am running connected components some powered from the transformer
and others direct to the house voltage. This is probably a bad idea,
but no amount of fiddling seems to remove the hum from my speakers, or
add it anywhere else.

I suppose I could solve the problem by throwing enough money at a new
receiver or power amp, but I just like tinkering with problems,
solving them myself, and keeping my money. (Example: I drive a Saab
with 330,000km on it. It's still a great car!) Also, I like the
switching features on my Proton; separate listen and record out
selection, and pre-out and pwr-amp in jumpers. What new home theater
receiver has that?

Anyone know some details about hum, specifically in the 50hz range?

Robobass

If you are getting the hum out of the speakers, and you do not have a
shielding problem from the interconnects, this means that the main filter
caps in the power supply have to be changed.

One test is to disconnect all the interconnects, and see if there is still
hum. If so, get the unit serviced.

The power transformer in the unit is most likely running hotter, because it
was probably designed to run on 60 Hz. It would not hurt to replace the main
filter caps with ones of a bit of a higher "uF" rating, if there is enough
physical space. An experienced technician should know what to do with this
problem.

--

Jerry G.
=====


"robobass" wrote in message
om...
I have read posts on this subject, but seen no real solutions:

I moved from USA to Germany two years ago. I brought along some audio
gear. I found a 500w transformer on ebay.de that gives me roughly 120v
and runs everything pretty much without a hitch, except for my Proton
D940 Receiver. When I first plugged it in, everything was fine. But
after awhile a 50 hz hum started coming from the speakers. At first I
experimented with reversing the power plugs of both the transformer
and the receiver. I was able to make it go away, but it always came
back. Now any changes in wiring don't produce audible effect. What I
find interesting is that what I am getting is a low level 50hz hum in
the speakers that is independant of the volume control, so it is not a
problem when I am cranking, only when I want to work at the computer
late at night, like now. Also, this hum seems to not affect preamp
circuits, as I can transfer audio from vinyl to digital without
picking up the hum, for example.

The transformer itself is audible even without load. That probably
points a finger, but I am wondering if this a problem without a
solution. I have often noticed audible hum in neighbors' stereo units.
Is 50 hz inherently harder to filter? Also, I brought a Hartke bass
amplifier which was dual voltage, 50/60. It works, but the unit itself
hums like mad. Interestingly, the hum does not come out of the
speakers significantly.

I do not know details of German house wiring and grounding
configurations, but it seems that it is single phase with one side
roughly 227v and the other neutral to ground. I measure no potential
between neutral, electrical ground, and earth ground (i.e. my steam
radiator).

I am running connected components some powered from the transformer
and others direct to the house voltage. This is probably a bad idea,
but no amount of fiddling seems to remove the hum from my speakers, or
add it anywhere else.

I suppose I could solve the problem by throwing enough money at a new
receiver or power amp, but I just like tinkering with problems,
solving them myself, and keeping my money. (Example: I drive a Saab
with 330,000km on it. It's still a great car!) Also, I like the
switching features on my Proton; separate listen and record out
selection, and pre-out and pwr-amp in jumpers. What new home theater
receiver has that?

Anyone know some details about hum, specifically in the 50hz range?

Robobass

En robobass va escriure en 22 Jun 2004 16:28:13 -0700:

When I first plugged it in, everything was fine. But
after awhile a 50 hz hum started coming from the speakers.

Have a look at "Jensen System Troubleshooting Guide" at

http://www.jensen-transformers.com/an/ts_guide.pdf

and other application notes at

http://www.jensen-transformers.com/apps_wp.html


Hope it helps,

Toni

En robobass va escriure en 22 Jun 2004 16:28:13 -0700:

When I first plugged it in, everything was fine. But
after awhile a 50 hz hum started coming from the speakers.

Have a look at "Jensen System Troubleshooting Guide" at

http://www.jensen-transformers.com/an/ts_guide.pdf

and other application notes at

http://www.jensen-transformers.com/apps_wp.html


Hope it helps,

Toni

En robobass va escriure en 22 Jun 2004 16:28:13 -0700:

When I first plugged it in, everything was fine. But
after awhile a 50 hz hum started coming from the speakers.

Have a look at "Jensen System Troubleshooting Guide" at

http://www.jensen-transformers.com/an/ts_guide.pdf

and other application notes at

http://www.jensen-transformers.com/apps_wp.html


Hope it helps,

Toni