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