Mains filter test results
 

Ok, as promised, results of tests with various filters, power cables etc...

First test on my own system, Arcam DV-79, AVR-250, Mordaunt-Short Avant
908/905C/903S speakers, B&W ASW-1000 sub, Audio Innovations Silver
Bi-Wire speaker cable.

As promised, I've been loaned an Isotek power cable (£60) in order to
carry out these tests. I was also loaned an Isotek power distribution
block (not sure of price, I think they're about £150).

For comparison, I also used a standard IEC mains cable, and an IEC cable
with a filtered plug.

I normally have my system plugged in via a Masterplug surge protected
and RFI-filtered 4-way distribution block, £8 trade or £20 retail.

For a test track I decided to use "So Far Away", from Dire Straits'
"Brothers In Arms" CD. The version in question is the SBM remaster.

Two other people were also present. One person was unsure, the other was
a complete sceptic.

First things first, I plugged the DVD player and amplifier into an
unfiltered block. I then played the test track.

I then switched power cables on the DVD player to use the Isotek, and
played the track again. This made no difference whatsoever - which is to
be expected, as the DVD player is merely acting as a transport. I
switched cables back again and played the test track to be sure, and
indeed there was no difference.

I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth.

I switched back to the standard IEC cable and listened again to ensure
that there was in fact a difference and that I wasn't imagining things.
The sound seemed flat after switching back.

Next I tried the standard cable with filtered plug. This again made
quite a dramatic difference to dynamics. Perhaps not quite so much as
the Isotek cable, but that may be the psychological bit coming into
play. But maybe not, as later tests showed.

I then brought filtered mains distribution blocks into play, and tried
various combinations of esoteric and generic branded filters, unfiltered
cables etc.

What I discovered (and the two other people in the room also heard quite
clearly) was that a filtered distribution block makes a difference, but
there did not appear to be any audible difference between the Isotek
block at £150 or the Masterplug block. Both have RFI filtering and surge
protection, the Isotek has a metal case, the Masterplug is plastic. But
none of us could hear a difference between them.

Also, the Isotek cable sounded exactly the same when plugged into an
unfiltered or filtered block. The generic filtered cable sounded
slightly better when connected via an RFI filtered block.

The combination of generic filtered cable and Masterplug filtered block
sounded as good as using the £60 Isotek cable. Both sounded
significantly better than using an unfiltered cable.

So on this basis I would recommend the Masterplug filtered 4-way block,
£8 from CPC or anything up to £20 retail, along with a filtered plug on
the IEC cable (costs about £3.50 from CPC, not sure about retail).

However, the next part of the test was interesting. We then went around
to a friend's house, who has a similar setup to mine - Arcam CD73, A90,
B&W DM603 speakers, QED speaker cables (not sure which one, but nice and
thick).

We then performed the same series of tests, and obtained a similar set
of results. However, the differences on his system weren't anywhere near
as dramatic as on mine.

So we then shut down and unplugged his PC, in the next room but on the
same ring main, and repeated the experiments.

This time the differences were negligibly small. We heard a tiny
improvement when using either the Isotek or generic filtered cables, and
a similar improvement when using the filtered mains blocks. This time we
didn't hear any difference between a filtered and unfiltered IEC cable
when used with a filtered block.

We plugged the PC back in and fired it up again, and repeated several
times for consistency. Once again the results with filtered mains were
much more noticeable when the PC was turned on.

So, in summary:

If you don't have any computer equipment (or anything with switch-mode
power supplies) on the same ring main as your hi-fi, buy a Masterplug
RFI filtered 4-way strip, if for no other reason than it incorporates
surge protection, so will protect your kit against voltage spikes.
(Believe me, I've seen quite a few PSUs fried by this type of thing.) If
it makes it sound better then that's a bonus. If it doesn't, well, at
least you know your equipment is protected.

If you have one or two PCs in the house that aren't left on all the
time, get the RFI filtered block. Try using a filtered IEC cable and
listen, if it makes a difference then keep using it.

If you've got a miniature version of Docklands Telehouse in your attic
or spare room, stick an RFI filtered 4-way block in, then use filtered
power cables from that. It's also probably worth putting filtered cables
on your PCs and other items with SMPSUs, as then you'll tackle the
problem at source (and additionally protect *that* expensive equipment
from spikes).

In the meantime, I appear to have "won" an Isotek power cable worth £60.
They want the distribution block back, but they've said I can hang on to
the power cable for now. Might try opening up the plug and see exactly
what type of filter they've put in...

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

Mains filter test results
 

In article , Glenn Richards wrote:
[...]
I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth.

I switched back to the standard IEC cable and listened again to ensure
that there was in fact a difference and that I wasn't imagining things.
The sound seemed flat after switching back.

Next I tried the standard cable with filtered plug. This again made
quite a dramatic difference to dynamics. Perhaps not quite so much as
the Isotek cable, but that may be the psychological bit coming into
play. But maybe not, as later tests showed.
[...]

Did you measure anything objectively with instruments? Anything at all?
Doesn't it ever cross your mind how remarkable it is that after the mains
current has travelled all those miles underground and overhead, the last
few feet can make such a difference? Are you sure you're really hearing
what you think you're hearing?

Rod.

Mains filter test results
 

On Mon, 20 Mar 2006 00:51:28 -0000, Roderick Stewart
wrote:

Did you measure anything objectively with instruments? Anything at all?
Doesn't it ever cross your mind how remarkable it is that after the mains
current has travelled all those miles underground and overhead, the last
few feet can make such a difference? Are you sure you're really hearing
what you think you're hearing?

He's suggesting that a filtered power lead can reduce interference
from an adjacent computer. Not that it's improving the mains supply
as such.

Mains filter test results
 

Glenn Richards wrote:

What I discovered (and the two other people in the room also heard quite
clearly) was that a filtered distribution block makes a difference, but
there did not appear to be any audible difference between the Isotek
block at £150 or the Masterplug block. Both have RFI filtering and surge
protection, the Isotek has a metal case, the Masterplug is plastic. But
none of us could hear a difference between them.


What you discovered was that a particular amplifier sounded better to three
people under certain circumstances, no more, no less.

Ian

Mains filter test results
 

In article 441e64e4.0@entanet, Ian Bell wrote:
Glenn Richards wrote:

What I discovered (and the two other people in the room also heard
quite clearly) was that a filtered distribution block makes a
difference, but there did not appear to be any audible difference
between the Isotek block at £150 or the Masterplug block. Both have
RFI filtering and surge protection, the Isotek has a metal case, the
Masterplug is plastic. But none of us could hear a difference between
them.


What you discovered was that a particular amplifier sounded better to
three people under certain circumstances, no more, no less.

Not quite. It was 'discovered' that they had this opinion... However the
'test' as reported shows no signs of being reliable beyond that.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Mains filter test results
 

In article , Glenn Richards
wrote:
Ok, as promised, results of tests with various filters, power cables
etc...

[snip]

First things first, I plugged the DVD player and amplifier into an
unfiltered block. I then played the test track.

I then switched power cables on the DVD player to use the Isotek, and
played the track again. This made no difference whatsoever - which is to
be expected, as the DVD player is merely acting as a transport. I
switched cables back again and played the test track to be sure, and
indeed there was no difference.

You presumably were aware thoughout of what arrangement was in use. You
also seem to have only done this a few times, not many times to form
abody of data on which any meaningful statistical analysis could be
carried out.

I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth.

....or at least that was the impression of those involved.


[snip]

What I discovered (and the two other people in the room also heard quite
clearly) was that a filtered distribution block makes a difference, but
there did not appear to be any audible difference between the Isotek
block at £150 or the Masterplug block. Both have RFI filtering and surge
protection, the Isotek has a metal case, the Masterplug is plastic. But
none of us could hear a difference between them.

The problem is that no-one else at this point can tell if your opinions
have any weight or not since your test method may not be reliable, and
you give no data which others could uses to assess the validity or
statistical reliability of what you report.

If you wish to obtain valid results which can be used as a reliable guide
then you would at least have to:

A) Do some tests where the results can be shown to depend *only* on the
sounds being produced. i.e. ensure that those involved don't know which of
the items being compared are in use at any point when having to make
decisions.

B) Do the tests enough times to allow the results to be assessed for level
of statistical significance.

It might also help if you'd tried actually measuring or examining the
output from the system to see if you could find any changes that might
account for the opinions you formed.

It would also help to take measures to check for, or control the risk
of interpreting an effect due to some other cause as being due to
what you may incorrectly assume. e.g. ensure that you have enough
test runs to deal with alterations in listening position (acoustics)
and reverse ordering to deal with psycho- or physio- adaptions due
to immdiately previous experiences.

In this particular case, it would have been useful to repeat the tests
in your friend's house, with someone else in another room either having
the PC (alleged to be the source of assumed 'interference') on or off,
and have you say which was the case simply by listening. If you could
do this repeatedly and get the answer correct then that would be a
useful result. But if you know the PC is on or off when listening, then
it is not really very useful.

Alas, in the absence of the above, the report you make tells us about the
opinions of those involved, but does not tell us if the cables, etc,
actually did anything to the output of the system. Nor if this had
anything to do with 'filtering'.

IIUC it has been explained on more than one occasion in the past that such
'tests' do need to be carried out in an appropriate manner if we wish the
results to have any reliability as evidence. It therefore seems a shame
that you seem not to have done this. The result is that your opinions
may or may not be well-founded, and no-one can tell which since either
possibility will seem equally probable to anyone other than yourself.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Mains filter test results
 

In the meantime, I appear to have "won" an Isotek power cable worth £60.
They want the distribution block back, but they've said I can hang on to
the power cable for now. Might try opening up the plug and see exactly
what type of filter they've put in...


Yes, see what's adding in extra resistance and or inductance.

Don't fancy doing it all again with a storage scope across the mains to
see what's happening to the waveform and voltage?, to see if the
filters/power cords etc are seriously affecting the mains power
increasing the source impedance etc, into the units under test?........

--
Tony Sayer

Mains filter test results
 

In article , Roderick
Stewart writes
In article , Glenn Richards wrote:
[...]
I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth.

I switched back to the standard IEC cable and listened again to ensure
that there was in fact a difference and that I wasn't imagining things.
The sound seemed flat after switching back.

Next I tried the standard cable with filtered plug. This again made
quite a dramatic difference to dynamics. Perhaps not quite so much as
the Isotek cable, but that may be the psychological bit coming into
play. But maybe not, as later tests showed.
[...]

Did you measure anything objectively with instruments? Anything at all?
Doesn't it ever cross your mind how remarkable it is that after the mains
current has travelled all those miles underground and overhead, the last
few feet can make such a difference? Are you sure you're really hearing
what you think you're hearing?


Perhaps he is hearing/imaging some change. Course if I stuck some
inductance resistance into the mains on my amp etc, I would expect it
the behave differently, wouldn't expect it to behave any better tho!..

BTW was there any RF present to speak of when U were doing all this?...
Rod.


--
Tony Sayer

Mains filter test results
 

"tony sayer" wrote in message
...
In the meantime, I appear to have "won" an Isotek power cable worth £60.
They want the distribution block back, but they've said I can hang on to
the power cable for now. Might try opening up the plug and see exactly
what type of filter they've put in...


Yes, see what's adding in extra resistance and or inductance.

Don't fancy doing it all again with a storage scope across the mains to
see what's happening to the waveform and voltage?, to see if the
filters/power cords etc are seriously affecting the mains power
increasing the source impedance etc, into the units under test?........

--
Tony Sayer


I was about to say exactly the same thing as Tony. I don't doubt that Glenn
and his chums thought that they heard some difference - and perhaps they
did. I'm certainly not going to join the " it's all just a load of ********
" brigade on this BUT, if adding in filtering ahead of the equipment really
DID produce a difference, then in order to evaluate the true validity of the
perceived improvement, we would need to know exactly what the filters were
filtering against, and how effectively. A high bandwidth storage scope would
be a satisfactory way of doing this. If the filters are indeed removing
mains-injected hash from a single computer's power supply, then firstly, you
would have to question if that computer's power supply and input filtering,
were working correctly. If there is sufficient level to have a siginificant
enough effect to hear, being introduced by this computer, then it would
almost certainly be operating outside of it's CE approval ( assuming that
it's got one ). Strictly speaking, if it hasn't, and is introducing hash to
the mains supply, you render yourself liable to prosecution ...

Secondly, if the computer is within spec regarding its emmissions, then you
would have to question why an expensive amplifier is being affected to a
degree that you can hear, by such a low level of mains borne noise ? If this
is indeed the case, and the amp is CE approved, then it should not respond
to such low levels, introduced through its mains port. Indeed, if you
contact the manufacturer and ask nicely, they might be able to produce a
copy of the CE test report for you, or at least tell you what figures were
achieved for noise immunity.

Either way, if you want to progress this discussion further, in a sensible
way, we need to see some objective test results as to what the filters were
doing, otherwise, this thread will just degenerate into another long string
of insults and taunts and challenges, that are meaningless, and time
wasting, and do nothing for the credibility of the group.

Arfa

Mains filter test results
 

On Sun, 19 Mar 2006 23:42:23 +0000, Glenn Richards
wrote:

Ok, as promised, results of tests with various filters, power cables etc...

First test on my own system, Arcam DV-79, AVR-250, Mordaunt-Short Avant
908/905C/903S speakers, B&W ASW-1000 sub, Audio Innovations Silver
Bi-Wire speaker cable.

As promised, I've been loaned an Isotek power cable (£60) in order to
carry out these tests. I was also loaned an Isotek power distribution
block (not sure of price, I think they're about £150).

For comparison, I also used a standard IEC mains cable, and an IEC cable
with a filtered plug.

I normally have my system plugged in via a Masterplug surge protected
and RFI-filtered 4-way distribution block, £8 trade or £20 retail.

For a test track I decided to use "So Far Away", from Dire Straits'
"Brothers In Arms" CD. The version in question is the SBM remaster.

Two other people were also present. One person was unsure, the other was
a complete sceptic.

First things first, I plugged the DVD player and amplifier into an
unfiltered block. I then played the test track.

I then switched power cables on the DVD player to use the Isotek, and
played the track again. This made no difference whatsoever - which is to
be expected, as the DVD player is merely acting as a transport. I
switched cables back again and played the test track to be sure, and
indeed there was no difference.

I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth.

I switched back to the standard IEC cable and listened again to ensure
that there was in fact a difference and that I wasn't imagining things.
The sound seemed flat after switching back.

Next I tried the standard cable with filtered plug. This again made
quite a dramatic difference to dynamics. Perhaps not quite so much as
the Isotek cable, but that may be the psychological bit coming into
play. But maybe not, as later tests showed.

I then brought filtered mains distribution blocks into play, and tried
various combinations of esoteric and generic branded filters, unfiltered
cables etc.

What I discovered (and the two other people in the room also heard quite
clearly) was that a filtered distribution block makes a difference, but
there did not appear to be any audible difference between the Isotek
block at £150 or the Masterplug block. Both have RFI filtering and surge
protection, the Isotek has a metal case, the Masterplug is plastic. But
none of us could hear a difference between them.

Also, the Isotek cable sounded exactly the same when plugged into an
unfiltered or filtered block. The generic filtered cable sounded
slightly better when connected via an RFI filtered block.

The combination of generic filtered cable and Masterplug filtered block
sounded as good as using the £60 Isotek cable. Both sounded
significantly better than using an unfiltered cable.

So on this basis I would recommend the Masterplug filtered 4-way block,
£8 from CPC or anything up to £20 retail, along with a filtered plug on
the IEC cable (costs about £3.50 from CPC, not sure about retail).

However, the next part of the test was interesting. We then went around
to a friend's house, who has a similar setup to mine - Arcam CD73, A90,
B&W DM603 speakers, QED speaker cables (not sure which one, but nice and
thick).

We then performed the same series of tests, and obtained a similar set
of results. However, the differences on his system weren't anywhere near
as dramatic as on mine.

So we then shut down and unplugged his PC, in the next room but on the
same ring main, and repeated the experiments.

This time the differences were negligibly small. We heard a tiny
improvement when using either the Isotek or generic filtered cables, and
a similar improvement when using the filtered mains blocks. This time we
didn't hear any difference between a filtered and unfiltered IEC cable
when used with a filtered block.

We plugged the PC back in and fired it up again, and repeated several
times for consistency. Once again the results with filtered mains were
much more noticeable when the PC was turned on.

So, in summary:

If you don't have any computer equipment (or anything with switch-mode
power supplies) on the same ring main as your hi-fi, buy a Masterplug
RFI filtered 4-way strip, if for no other reason than it incorporates
surge protection, so will protect your kit against voltage spikes.
(Believe me, I've seen quite a few PSUs fried by this type of thing.) If
it makes it sound better then that's a bonus. If it doesn't, well, at
least you know your equipment is protected.

If you have one or two PCs in the house that aren't left on all the
time, get the RFI filtered block. Try using a filtered IEC cable and
listen, if it makes a difference then keep using it.

If you've got a miniature version of Docklands Telehouse in your attic
or spare room, stick an RFI filtered 4-way block in, then use filtered
power cables from that. It's also probably worth putting filtered cables
on your PCs and other items with SMPSUs, as then you'll tackle the
problem at source (and additionally protect *that* expensive equipment
from spikes).

In the meantime, I appear to have "won" an Isotek power cable worth £60.
They want the distribution block back, but they've said I can hang on to
the power cable for now. Might try opening up the plug and see exactly
what type of filter they've put in...

Well, this would all be a little more convincing if the changes you
"observed" were ones concerned with symptoms that might possibly be
addressed by cleaner power. These would be essentially (as Dave
Plowman pointed out), an absence of clicks from devices like
thermostats.

What you present here amounts to "I used Cillit Bang to clean my sink,
and yes, I was three inches taller as a result".

So no, yet again you have presented us with some nonsensical
pseudo-science to support something imaginary that you and your
friends convinced yourselves had happened.

d

Pearce Consulting
http://www.pearce.uk.com

Mains filter test results
 

Roderick Stewart wrote:

Doesn't it ever cross your mind how remarkable it is that after the
mains current has travelled all those miles underground and overhead,
the last few feet can make such a difference? Are you sure you're
really hearing what you think you're hearing?

It's not the cable that makes a difference so much as the filtering.
Which, I assume, is why the combination of Masterplug RFI filtered block
and generic IEC lead with filtered plug had the same effect as a £60
Isotek cable.

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

Mains filter test results
 

"Glenn Richards" wrote in message
...
Ok, as promised, results of tests with various filters, power cables etc...

First test on my own system, Arcam DV-79, AVR-250, Mordaunt-Short Avant
908/905C/903S speakers, B&W ASW-1000 sub, Audio Innovations Silver Bi-Wire
speaker cable.

As promised, I've been loaned an Isotek power cable (£60) in order to carry
out these tests. I was also loaned an Isotek power distribution block (not
sure of price, I think they're about £150).

For comparison, I also used a standard IEC mains cable, and an IEC cable with
a filtered plug.

I normally have my system plugged in via a Masterplug surge protected and
RFI-filtered 4-way distribution block, £8 trade or £20 retail.

For a test track I decided to use "So Far Away", from Dire Straits' "Brothers
In Arms" CD. The version in question is the SBM remaster.

Two other people were also present. One person was unsure, the other was a
complete sceptic.

First things first, I plugged the DVD player and amplifier into an unfiltered
block. I then played the test track.

I then switched power cables on the DVD player to use the Isotek, and played
the track again. This made no difference whatsoever - which is to be expected,
as the DVD player is merely acting as a transport. I switched cables back
again and played the test track to be sure, and indeed there was no
difference.

I then switched the power cable on the amplifier to use the Isotek cable.
Immediately there was an improvement in dynamics, percussion in particular had
much more presence and depth.

I switched back to the standard IEC cable and listened again to ensure that
there was in fact a difference and that I wasn't imagining things. The sound
seemed flat after switching back.

Next I tried the standard cable with filtered plug. This again made quite a
dramatic difference to dynamics. Perhaps not quite so much as the Isotek
cable, but that may be the psychological bit coming into play. But maybe not,
as later tests showed.

I then brought filtered mains distribution blocks into play, and tried various
combinations of esoteric and generic branded filters, unfiltered cables etc.

What I discovered (and the two other people in the room also heard quite
clearly) was that a filtered distribution block makes a difference, but there
did not appear to be any audible difference between the Isotek block at £150
or the Masterplug block. Both have RFI filtering and surge protection, the
Isotek has a metal case, the Masterplug is plastic. But none of us could hear
a difference between them.

Also, the Isotek cable sounded exactly the same when plugged into an
unfiltered or filtered block. The generic filtered cable sounded slightly
better when connected via an RFI filtered block.

The combination of generic filtered cable and Masterplug filtered block
sounded as good as using the £60 Isotek cable. Both sounded significantly
better than using an unfiltered cable.

So on this basis I would recommend the Masterplug filtered 4-way block, £8
from CPC or anything up to £20 retail, along with a filtered plug on the IEC
cable (costs about £3.50 from CPC, not sure about retail).

However, the next part of the test was interesting. We then went around to a
friend's house, who has a similar setup to mine - Arcam CD73, A90, B&W DM603
speakers, QED speaker cables (not sure which one, but nice and thick).

We then performed the same series of tests, and obtained a similar set of
results. However, the differences on his system weren't anywhere near as
dramatic as on mine.

So we then shut down and unplugged his PC, in the next room but on the same
ring main, and repeated the experiments.

This time the differences were negligibly small. We heard a tiny improvement
when using either the Isotek or generic filtered cables, and a similar
improvement when using the filtered mains blocks. This time we didn't hear any
difference between a filtered and unfiltered IEC cable when used with a
filtered block.

We plugged the PC back in and fired it up again, and repeated several times
for consistency. Once again the results with filtered mains were much more
noticeable when the PC was turned on.


So this friend who believes his ears demand fancy speaker cables had never
noticed that his computer was degrading the sound of his system?

With two friends, you had the opportunity to do the test blind. Why didn't you?

Does anyone know what frequencies are removed by mains filters? How should I
choose between them? Is there a standard? Do they all offer the same
attenuation?

If not then, as with fancy speaker cables, what explains the variety when they
all have the same purpose?

cheers, Ian

So, in summary:

If you don't have any computer equipment (or anything with switch-mode power
supplies) on the same ring main as your hi-fi, buy a Masterplug RFI filtered
4-way strip, if for no other reason than it incorporates surge protection, so
will protect your kit against voltage spikes. (Believe me, I've seen quite a
few PSUs fried by this type of thing.) If it makes it sound better then that's
a bonus. If it doesn't, well, at least you know your equipment is protected.

If you have one or two PCs in the house that aren't left on all the time, get
the RFI filtered block. Try using a filtered IEC cable and listen, if it makes
a difference then keep using it.

If you've got a miniature version of Docklands Telehouse in your attic or
spare room, stick an RFI filtered 4-way block in, then use filtered power
cables from that. It's also probably worth putting filtered cables on your PCs
and other items with SMPSUs, as then you'll tackle the problem at source (and
additionally protect *that* expensive equipment from spikes).

In the meantime, I appear to have "won" an Isotek power cable worth £60. They
want the distribution block back, but they've said I can hang on to the power
cable for now. Might try opening up the plug and see exactly what type of
filter they've put in...

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

Mains filter test results
 

Laurence Payne wrote:

He's suggesting that a filtered power lead can reduce interference
from an adjacent computer. Not that it's improving the mains supply
as such.

The other thing we noticed, that when I re-read my post I seem to have
omitted (I'm sure I remember typing this bit, obviously not though)...

Whilst doing the second part of the test round at a friend's house, we
also tried putting the filtered cables onto his PC instead of the hi-fi.
The results from this were the same as when the PC was turned off.

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

Mains filter test results
 

Don Pearce wrote:

Well, this would all be a little more convincing if the changes you
"observed" were ones concerned with symptoms that might possibly be
addressed by cleaner power. These would be essentially (as Dave
Plowman pointed out), an absence of clicks from devices like
thermostats.

And an absence of mains-bourne RF hash from the switching PSU in a PC...

(BTW, did you have to do an AOL and quote my entire post with only a
dozen lines of text? It's only one step away from top-posted HTML...)

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

Mains filter test results
 

On Mon, 20 Mar 2006 10:55:44 +0000, Glenn Richards
wrote:

Don Pearce wrote:

Well, this would all be a little more convincing if the changes you
"observed" were ones concerned with symptoms that might possibly be
addressed by cleaner power. These would be essentially (as Dave
Plowman pointed out), an absence of clicks from devices like
thermostats.

And an absence of mains-bourne RF hash from the switching PSU in a PC...

(BTW, did you have to do an AOL and quote my entire post with only a
dozen lines of text? It's only one step away from top-posted HTML...)

Far better than clipping the part that actually needed a response.

And it is mains-borne, not mains-bourne - this has nothing to do with
small streams.

And once again, RF is NOT audio.

d

Pearce Consulting
http://www.pearce.uk.com

Mains filter test results
 

Arfa Daily wrote:

Secondly, if the computer is within spec regarding its emmissions, then you
would have to question why an expensive amplifier is being affected to a
degree that you can hear, by such a low level of mains borne noise ?

Could be a high-end amp with capacitors bypassing the psu diodes to reduce
'diode switching noise'
and let through RF - thus creating a market for special filtered mains cables.

--
Eiron

There's something scary about stupidity made coherent - Tom Stoppard.

Mains filter test results
 

In article , Laurence Payne
wrote:
Did you measure anything objectively with instruments? Anything at all?
Doesn't it ever cross your mind how remarkable it is that after the mains
current has travelled all those miles underground and overhead, the last
few feet can make such a difference? Are you sure you're really hearing
what you think you're hearing?

He's suggesting that a filtered power lead can reduce interference
from an adjacent computer. Not that it's improving the mains supply
as such.

Then why does he use language like this.....?

"I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth".

What he seems to be talking about is a change in the sound quality. He
doesn't mention the sudden absence of "interference", nor what he thinks the
interference sounded like before the substitution.

Since he attributes the interference to the effects of switch-mode power
supplies in other equipment on the mains wiring, it would be interesting to
know if any of the audio equipment has this type of power supply, which I
believe is quite common. If so, is there a theory as to why the
"interference" only comes from a PC in the next room, but not from the audio
equipmenmt itself?

Rod.

Mains filter test results
 

On Mon, 20 Mar 2006 12:02:50 -0000, Roderick Stewart
wrote:

He's suggesting that a filtered power lead can reduce interference
from an adjacent computer. Not that it's improving the mains supply
as such.

Then why does he use language like this.....?

"I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth".

What he seems to be talking about is a change in the sound quality. He
doesn't mention the sudden absence of "interference", nor what he thinks the
interference sounded like before the substitution.

Since he attributes the interference to the effects of switch-mode power
supplies in other equipment on the mains wiring, it would be interesting to
know if any of the audio equipment has this type of power supply, which I
believe is quite common. If so, is there a theory as to why the
"interference" only comes from a PC in the next room, but not from the audio
equipmenmt itself?

Indeed, his logic is questionable. But you criticised him using the
"all the way back to the power station" argument. That wasn't
relevant to his claim of removing local power corruption.

Mains filter test results
 

In article , Eiron
wrote:
Arfa Daily wrote:

Secondly, if the computer is within spec regarding its emmissions,
then you would have to question why an expensive amplifier is being
affected to a degree that you can hear, by such a low level of mains
borne noise ?

Could be a high-end amp with capacitors bypassing the psu diodes to
reduce 'diode switching noise' and let through RF - thus creating a
market for special filtered mains cables.

If you use a set of bypass caps on the diodes it has the effect of blocking
any differential mode (Live-Neutral) noise via that route. If properly
referenced to RF ground it will also deal with common mode above ground. In
effect you can use it as part of ensuring all the power wiring is RF
shorted together and to local ground.

It also defines the RF impedance at the relevant points rather than
allowing it to change during each mains cycle and with current demand.

Hence in contrast with the implication of what you write, using such caps
to shunt the diodes can be a very effective way to block/reduce some of the
RF noise, clicks, etc. Provided it is done appropriately, of course.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Mains filter test results
 

Could I deign to suggest that if there is really any difference when
the filter plug is in place it is because it is reducing line noise
which had been getting through the (usually) poor PSU of the CD/DVD
player and upsetting it's decoding.

I think I am right in saying that it has been found that if the
decoding error rate is reduced on a CD player by whatever means - be
that new clean disc and/or a clean lens - as it is not struggling so
much to error-correct the decoded music the end result is a subjective
improvement?

One thing is sure. Most power supplies have some decent sized
electrolytics in them but few have any smaller value caps in parallel
to handle the higher frequencies. The late great John Lindsay-Hood
(and I seem to think Doug Self also) produced much on this topic
decades ago.


--
Woody

harrogate3 at ntlworld dot com

Mains filter test results
 

On Mon, 20 Mar 2006 18:08:54 GMT, "harrogate2"
wrote:

Could I deign to suggest that if there is really any difference when
the filter plug is in place it is because it is reducing line noise
which had been getting through the (usually) poor PSU of the CD/DVD
player and upsetting it's decoding.

This is British mains we are talking about here so no, you can't. We
are talking about someone with too much time on his hands, and a
desperate need for self validation.

I think I am right in saying that it has been found that if the
decoding error rate is reduced on a CD player by whatever means - be
that new clean disc and/or a clean lens - as it is not struggling so
much to error-correct the decoded music the end result is a subjective
improvement?

If errors are correctable, there is *no* difference. If errors are not
correctable, you get clicks and dropouts. There is no suggestion of
these. The claims suggest that digital bits are being changed in a
systematic way to affect dynamic range and other aspects of the
decoded signal. It all just beggars belief.

One thing is sure. Most power supplies have some decent sized
electrolytics in them but few have any smaller value caps in parallel
to handle the higher frequencies. The late great John Lindsay-Hood
(and I seem to think Doug Self also) produced much on this topic
decades ago.

Power supplies are just fine, and the common mode rejection ratio of
balanced amplifier stages is even better. If there were any kind of
problem possible with a balanced solid state amp, then a singled ended
valve amp plugged into the same supply would be driven to limiting by
mains-borne noise.

d

Pearce Consulting
http://www.pearce.uk.com

Mains filter test results
 

"harrogate2" wrote in message
...
[clip]

One thing is sure. Most power supplies have some decent sized
electrolytics in them but few have any smaller value caps in parallel
to handle the higher frequencies. The late great John Lindsay-Hood
(and I seem to think Doug Self also) produced much on this topic
decades ago.


--
Woody

harrogate3 at ntlworld dot com



Thats one of the first thing many DIYers do.

Mike

Mains filter test results
 

On Mon, 20 Mar 2006 10:09:23 +0000, Arfa Daily wrote:

snip
were working correctly. If there is sufficient level to have a siginificant
enough effect to hear, being introduced by this computer, then it would
almost certainly be operating outside of it's CE approval ( assuming that
it's got one ). Strictly speaking, if it hasn't, and is introducing hash to
the mains supply, you render yourself liable to prosecution ...

snip

Please don't start thinking that the CE mark is some sort of quality
symbol. It isn't. If a piece of equipment carries that mark then the
manufacturer is supposed to be able to produce documentation to show that
it was *designed to be* within the stated specification and that it
complies with the Low Voltage Directive (or its equivalent). If the spec
doesn't mention that the device may radiate at RF then it *may* still be
able to carry the CE mark! The purpose of the CE mark is to allow
equipment to pass European borders without having to produce all sorts of
test results etc for each piece of equipment. It is supposed to give
confidence that the spec means something and the device won't give
electric shocks or blow up when plugged in. Pretty basic really!

--
Mick (Working in a M$-free zone!)
Remove blockage to use my email address
Web: http://www.nascom.info & http://mixpix.batcave.net

Mains filter test results
 

Roderick Stewart wrote:

"I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth".

Which would make perfect sense, as by taking out RF interference what
you've done is lowered the noise floor. You may not be able to hear RF,
but if your amplifier is trying to reproduce it then it's increased the
noise floor, which will result in the dynamic range of the system being
reduced.

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

Mains filter test results
 

Jim Lesurf wrote:

You presumably were aware thoughout of what arrangement was in use. You
also seem to have only done this a few times, not many times to form
abody of data on which any meaningful statistical analysis could be
carried out.

We didn't worry about setting up a blind test at this stage, as my
concern was simply to find out whether there was a difference,
perceived, psychological, whatever.

From my point of view I'm satisfied with the results. Using an RFI
filtered 4-way strip in combination with a generic filtered IEC lead
will get rid of the RF hash on the mains supply, and thereby lower the
noise floor (and improve dynamics). These bits can be had at trade price
for about £8 for the 4-way block, and less than a fiver for a bare-ended
IEC cable and a filtered 13A plug. Use the two together and it's just as
effective as an Isotek cable (£60).

When you have the amount of PC hardware on your ring main as I do (WinXP
and NetBSD workstations in the dining room/office, 10 servers in the
attic, RISC PC in one bedroom, A3020 in another bedroom, plus a couple
of laptops, then all the Ethernet switches, wireless access point etc
all spewing RF onto the mains) then decent RFI filtering on the mains
does make a difference. And even if you're living out in the middle of
nowhere, with no PCs or SMPSUs for miles, it's worth having a surge
protected strip anyway.

Quick question - in the event of a lightning strike, what would you
rather have fried? £8 worth of surge protected mains distribution block,
or £1,000 worth of amplifier?

Bit of a no-brainer really, that one.

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

Mains filter test results
 

"Roderick Stewart" wrote
in message
om
In article , Glenn
Richards wrote: [...]
I then switched the power cable on the amplifier to use
the Isotek cable. Immediately there was an improvement
in dynamics, percussion in particular had much more
presence and depth.

I switched back to the standard IEC cable and listened
again to ensure that there was in fact a difference and
that I wasn't imagining things. The sound seemed flat
after switching back.

Next I tried the standard cable with filtered plug. This
again made quite a dramatic difference to dynamics.
Perhaps not quite so much as the Isotek cable, but that
may be the psychological bit coming into play. But maybe
not, as later tests showed.
[...]

Did you measure anything objectively with instruments?

Test instruments? Nahh, being a typical golden ear Glenn blew it all on
tweeks and overpriced high end components.

Anything at all? Doesn't it ever cross your mind how
remarkable it is that after the mains current has
travelled all those miles underground and overhead, the
last few feet can make such a difference?

Think of it this way - here's Glenn's opportunity to wrestle with science
and being judge and jury, declare himself the winnner.

Are you sure you're really hearing what you think you're hearing?

Of course he does - self-doubt comes with self-awareness.

Mains filter test results
 

In article , Glenn Richards wrote:
"I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth".

Which would make perfect sense, as by taking out RF interference what
you've done is lowered the noise floor. You may not be able to hear RF,
but if your amplifier is trying to reproduce it then it's increased the
noise floor, which will result in the dynamic range of the system being
reduced.

And the increase in "presence and depth" on percussion was the only thing
that was noticed?

Don't you think that if the noise floor was the only thing that the RF
interference caused (which seems a trifle unlikely if it really was RF
interference), it would simply be audible as noise? Why the need to listen
to music subjectively and write about it in flowery language? Why not just
measure the noise?

Rod.

Mains filter test results
 

"mick" wrote in message
news:pan.2006.03.20.19.56.44.574826@SPAMBLOCKmixte l.co.uk...
On Mon, 20 Mar 2006 10:09:23 +0000, Arfa Daily wrote:

snip
were working correctly. If there is sufficient level to have a
siginificant
enough effect to hear, being introduced by this computer, then it would
almost certainly be operating outside of it's CE approval ( assuming that
it's got one ). Strictly speaking, if it hasn't, and is introducing hash
to
the mains supply, you render yourself liable to prosecution ...

snip

Please don't start thinking that the CE mark is some sort of quality
symbol. It isn't. If a piece of equipment carries that mark then the
manufacturer is supposed to be able to produce documentation to show that
it was *designed to be* within the stated specification and that it
complies with the Low Voltage Directive (or its equivalent). If the spec
doesn't mention that the device may radiate at RF then it *may* still be
able to carry the CE mark! The purpose of the CE mark is to allow
equipment to pass European borders without having to produce all sorts of
test results etc for each piece of equipment. It is supposed to give
confidence that the spec means something and the device won't give
electric shocks or blow up when plugged in. Pretty basic really!

--
Mick (Working in a M$-free zone!)
Remove blockage to use my email address
Web: http://www.nascom.info & http://mixpix.batcave.net


It is not the Low Voltage Directive that deals with the interference issue
specifically. It is ( originally ) 89/336/EEC, the Electro Magnetic
Compatibility Directive. Both computer equipment, and audio equipment must
comply with this directive, which refers not only to interference caused by
directly radiated fields, but also interference caused to the mains supply
by any piece of covered equipment, and the response of any covered
equipment, to such interference. As I understand it, compliance with this
directive is a requirement before a CE mark can be placed on an item, and it
is required that covered goods carry such a mark, before they can be offered
for sale, or even use within the EU.

There are bound to be loopholes and get arounds, and self-certifiers who get
it wrong, but the general 'spirit' of CE marking assures a *degree* of
quality in respect of EMC and interference immunity, as well as the other
things such as safety, referred to in the Low Voltage Directive,
theoretically under threat of law.

I stand by what I said originally, that if a computer power supply is
putting enough garbage out onto a mains ring, to affect a piece of audio
equipment, on the same ring, but in another room, to a degree where the
reproductive quality is affected, then either the power supply is operating
outside of the requirements of the EMC directive, as designed, or it is
faulty. Likewise, if a CE marked piece of audio equipment is responding to
the minimal level of hash put onto the mains by a correctly operating and CE
compliant power supply, then it is either faulty in some way, or it has not
been designed and tested correctly in the first place, and its marked CE
compliance, is a lie.

Arfa

Mains filter test results
 

In article , Glenn Richards
wrote:
Roderick Stewart wrote:

"I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth".

Which would make perfect sense, as by taking out RF interference what
you've done is lowered the noise floor. You may not be able to hear RF,
but if your amplifier is trying to reproduce it then it's increased the
noise floor, which will result in the dynamic range of the system being
reduced.

You give no explanation of how the amplifier would be "trying to reproduce"
the RF and this then leads to it "inceasing the noise floor".

Thus you make a speculation, but give no mechanism.

Nor did you report any measurement or period of listening that showed that
you could detect a change in the audible noise floor. If this was occuring,
it would show most clearly when you were not playing any music, and the
effect would then be obvious if it was occurring.

Thus you did some 'tests' but obtained no evidence that the effect your
speculation assumes actually occurred.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Mains filter test results
 

In article , Glenn Richards
wrote:
Jim Lesurf wrote:

You presumably were aware thoughout of what arrangement was in use.
You also seem to have only done this a few times, not many times to
form abody of data on which any meaningful statistical analysis could
be carried out.

We didn't worry about setting up a blind test at this stage, as my
concern was simply to find out whether there was a difference,
perceived, psychological, whatever.

From my point of view I'm satisfied with the results.

That would be fine for you - if you had not then posted your opinions here
as if your 'test' had any reliability or value for anyone else. :-)

Alas, since your 'test' was not conducted in an appropriate manner, your
report will be unlikely to have eithe 'satisfied' or been of any use to
anyone else.

[snip]

Quick question - in the event of a lightning strike, what would you
rather have fried? £8 worth of surge protected mains distribution block,
or £1,000 worth of amplifier?

Bit of a no-brainer really, that one.

Indeed. :-) Particulary since a lightning strike may well crisp the
'surge protection' *and* the rest of the equipment locally connected. I'm
afraid that a small VDR isn't likely to be able to absorb the energy of a
nearby lightning strike. :-)

Nor is a VDR likely to be much use against RF spikes as it laregly converts
a voltage spike into a current pulse. So may still allow 'clicks' though if
the units you wish to 'protect' don't have decen PSU, grounding, etc.

If you wish to avoid clicks and pops from audio gear, then go for decent
kit, and perhaps suppliment it with *filters*, not a 'surge protection'
unit.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Mains filter test results
 

In article , Glenn Richards
writes
Roderick Stewart wrote:

"I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth".

Which would make perfect sense, as by taking out RF interference what
you've done is lowered the noise floor. You may not be able to hear RF,
but if your amplifier is trying to reproduce it then it's increased the
noise floor, which will result in the dynamic range of the system being
reduced.


Glenn,

do you live somewhere like Brookmans Park or Holme Moss?. Never known a
bloke to be troubled by so much RF!......
--
Tony Sayer

Mains filter test results
 

In article , Glenn Richards
writes
Jim Lesurf wrote:

You presumably were aware thoughout of what arrangement was in use. You
also seem to have only done this a few times, not many times to form
abody of data on which any meaningful statistical analysis could be
carried out.

We didn't worry about setting up a blind test at this stage, as my
concern was simply to find out whether there was a difference,
perceived, psychological, whatever.

Ah!, If your after the feel good factor going to church on Sundays or an
old s/hand bible might achieve that!.....

From my point of view I'm satisfied with the results. Using an RFI
filtered 4-way strip in combination with a generic filtered IEC lead
will get rid of the RF hash on the mains supply, and thereby lower the
noise floor (and improve dynamics). These bits can be had at trade price
for about £8 for the 4-way block, and less than a fiver for a bare-ended
IEC cable and a filtered 13A plug. Use the two together and it's just as
effective as an Isotek cable (£60).

When you have the amount of PC hardware on your ring main as I do (WinXP
and NetBSD workstations in the dining room/office, 10 servers in the
attic, RISC PC in one bedroom, A3020 in another bedroom, plus a couple
of laptops, then all the Ethernet switches, wireless access point etc
all spewing RF onto the mains) then decent RFI filtering on the mains
does make a difference. And even if you're living out in the middle of
nowhere, with no PCs or SMPSUs for miles, it's worth having a surge
protected strip anyway.

Quick question - in the event of a lightning strike, what would you
rather have fried? £8 worth of surge protected mains distribution block,
or £1,000 worth of amplifier?

O dear!, in the advent of a lightning strike make sure your insurance
covers your gear!....

Course going to church on Sunday might appease the almighty so your
protected!.....

Bit of a no-brainer really, that one.

Yep.. no brains at all.....


--
Tony Sayer

Mains filter test results
 

tony sayer wrote:

We didn't worry about setting up a blind test at this stage, as my
concern was simply to find out whether there was a difference,
perceived, psychological, whatever.
Ah!, If your after the feel good factor going to church on Sundays or
an old s/hand bible might achieve that!.....

Nope. Committed atheist, and have been ever since I was old enough to
know what it meant. (So about age 7 then...)

Quick question - in the event of a lightning strike, what would you
rather have fried? £8 worth of surge protected mains distribution
block, or £1,000 worth of amplifier?
O dear!, in the advent of a lightning strike make sure your insurance
covers your gear!....

Apparently with these Masterplug surge protected strips, Masterplug
themselves will guarantee to replace up to £4,000 worth of connected
equipment in the event of a power spike causing damage.

And as I've had a VCR get fried by a mains spike before (an old Ferguson
3V48... fortunately not a 3V43!) I tend to err on the side of caution
when it comes to power surges.

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

Mains filter test results
 

"Glenn Richards" wrote in
message
Jim Lesurf wrote:

You presumably were aware thoughout of what arrangement
was in use. You also seem to have only done this a few
times, not many times to form abody of data on which any
meaningful statistical analysis could be carried out.

We didn't worry about setting up a blind test at this
stage, as my concern was simply to find out whether there
was a difference, perceived, psychological, whatever.

Anybody with a clue about experimental design or psychology could predict
the outcome of your test without bothering to do it.

Mains filter test results
 

Arny Krueger wrote:

We didn't worry about setting up a blind test at this stage, as my
concern was simply to find out whether there was a difference,
perceived, psychological, whatever.
Anybody with a clue about experimental design or psychology could
predict the outcome of your test without bothering to do it.

The implication of what I wrote before was that if there appears to be a
difference (whether real or psychological) then it's worth the effort
and hassle of setting up a blind test. If there's no difference apparent
using a straight test then there's no point wasting time with blind testing.

However, as a straight test concluded that there was indeed a difference
(whether that difference was real or psychological is a matter for
debate, but the fact that three of us all heard the same effects would
suggest that the difference was indeed there) then it's perhaps worth
setting up a blind test.

As I appear to have won an Isotek power cable, at least for the time
being, I may well set up a blind test next time I've got a few hours to
waste. If I do so then I will of course post the results here.

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

Mains filter test results
 

In article , Tony sayer wrote:
"I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth".

Which would make perfect sense, as by taking out RF interference what
you've done is lowered the noise floor. You may not be able to hear RF,
but if your amplifier is trying to reproduce it then it's increased the
noise floor, which will result in the dynamic range of the system being
reduced.


Glenn,

do you live somewhere like Brookmans Park or Holme Moss?. Never known a
bloke to be troubled by so much RF!......
--
Tony Sayer

I think most technical "problems" with domestic gear are the product of a
lively but uninformed imagination. Also possibly the fact that a lot of
people never seem to outgrow their childhood instinct of believing what they
are told without questioning it provided they are told often enough by
people with the appearance of authority. Those that remain technically
ignorant but take up technical hobbies then spend their lives trying to
solve problems that don't exist. Either that or they keep on applying the
wrong remedies to problems that are of their own making because the
equipment hasn't been installed or set up correctly. I wonder how many
people who worry about RF actually know anything about it?

In my living room I have two PCs, one of them a wireless laptop which
normally lives on the same shelf unit as all the audio and video gear. The
wireless access point is only about 3 metres away, and just next to it is
the base station of a cordless phone, and my mobile phone is a similar
distance away on another shelf. Sometimes there are several other PCs in the
house if I am building or testing them for other people. The AV signals from
several disk recorders go through a SCART switch box and through about 5
metres of SCART cable to the TV set. I *think* all the TV and AV audio still
goes through the TV set before going back along several metres of phono
cables, but there's such a tangle of wiring which has been changed and added
to over the years that I'd have to check out the details, but certainly lots
of very ordinary cable. The kitchen is just next door and contains a fridge
with a thermostat, and there is another mains-switching thermostat on the
living room wall for the central heating.

And there isn't a single unwanted click, hiss or splat on the speakers from
any of this, ever. I can switch the amplifier to an unused input, turn the
volume control fully clockwise and put my head right in front of one of the
loudspeakers and hear nothing at all.

So why am I missing all the excitement? Everybody else seems to have to
tinker about solving endless technical problems with their hi-fi, but I just
connect everything together and sit back and enjoy the music without
worrying about anything, and it all works. The only problem I have that
*might* be RF based is that the radio-controlled wall clock tries to reset
itself at least once a day and is more often wrong than right, but there are
plenty of other gadgets that tell the time so it's not really important, and
if it annoys me once too often I can replace it with something from Ikea for
less than a fiver.

Rod.

Mains filter test results
 

Hi,

"Roderick Stewart" wrote in message

[snip description of a techno-den that sounds vaguely like my place]

And there isn't a single unwanted click, hiss or splat on the speakers from
any of this, ever. I can switch the amplifier to an unused input, turn the
volume control fully clockwise and put my head right in front of one of the
loudspeakers and hear nothing at all.

Ditto.

So why am I missing all the excitement?

You don't want to believe :-)

Everybody else seems to have to
tinker about solving endless technical problems with their hi-fi, but I just
connect everything together and sit back and enjoy the music without
worrying about anything, and it all works.

I don't think there's any 'have to' about it. I reckon some people 'want
to' tinker with endless technical problems. I'm a bit like that, but I put
it down to a thirst for knowledge (honest!) and I do my tinkering on
things that really might make a difference.

There are plenty of 'audiophiles' who are in it for the toys, not the music.
For those people who aren't _really_ in it for the music, there has to be some
twiddling to do in the endless (and fruitless) search for perfection, or it's
just
no fun. There's nothing wrong with that, except that it encourages the
******* that want to profit from naivety by selling snake oil.

In my book, if it ain't broke don't fix it.

Regards,

Glenn.

Mains filter test results
 

Roderick Stewart wrote:

I *think* all the TV and AV audio still goes through the TV set
before going back along several metres of phono cables, but there's
such a tangle of wiring which has been changed and added to over the
years that I'd have to check out the details, but certainly lots of
very ordinary cable.

Well, that just about says it all really.

The audio stage in most TVs is pretty poor, and if you're routing the AV
audio through the telly then it's going to sound bad.

The audio on my AV system goes nowhere near the TV, indeed the audio in
the SCART cable isn't even wired up. I've heard systems that were wired
up in this way, with all audio from AV (VCR, satellite box etc) routed
via the TV, and it sounded pretty horrible.

If that really is how you've got your system set up, and it sounds fine
to you, then don't waste your money on mains filters, interconnects,
silver speaker cable etc - as if you're happy with the way it sounds
like it is then you wouldn't appreciate the difference any of the
upgrades we've been discussing would make.

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

Mains filter test results
 

In article , Glenn Richards wrote:
I *think* all the TV and AV audio still goes through the TV set
before going back along several metres of phono cables, but there's
such a tangle of wiring which has been changed and added to over the
years that I'd have to check out the details, but certainly lots of
very ordinary cable.

Well, that just about says it all really.

The audio stage in most TVs is pretty poor, and if you're routing the AV
audio through the telly then it's going to sound bad.

The audio on my AV system goes nowhere near the TV, indeed the audio in
the SCART cable isn't even wired up. I've heard systems that were wired
up in this way, with all audio from AV (VCR, satellite box etc) routed
via the TV, and it sounded pretty horrible.

If that really is how you've got your system set up, and it sounds fine
to you, then don't waste your money on mains filters, interconnects,
silver speaker cable etc - as if you're happy with the way it sounds
like it is then you wouldn't appreciate the difference any of the
upgrades we've been discussing would make.

Just for the record, I've worked in broadcasting for 38 years, I'm not deaf
or stupid, and have plenty of experience of what many different kinds of
video and audio equipment look and sound like. You may have reached a
"decision" that my home AV setup cannot possibly perform well, based only
on my written description of it, but my own appraisal of it is based on
listening, watching, and comparing. Let's apply some logic please -
evidence first, *then* the conclusion.

Rod.

Mains filter test results
 

In article , Glenn Booth wrote:
You don't want to believe :-)

What I believe is based on what I can see and hear.

Everybody else seems to have to
tinker about solving endless technical problems with their hi-fi, but I just
connect everything together and sit back and enjoy the music without
worrying about anything, and it all works.

I don't think there's any 'have to' about it. I reckon some people 'want
to' tinker with endless technical problems. I'm a bit like that, but I put
it down to a thirst for knowledge (honest!) and I do my tinkering on
things that really might make a difference.

Good for you. I used to do a lot more of that too, until I reached a point where
the extra tinkering wasn't making any worthwhile improvement. As long as you
don't bother with things that defy reason or the laws of physics, and are honest
with yourself about what you can really hear, and follow up as much as you can
with objective measurements, then you'll make progress.

Rod.