Mains filters
 

"Don Pearce" wrote in message
...
On Thu, 16 Mar 2006 09:10:30 +0000, Glenn Richards
wrote:

Don Pearce wrote:

I ask a serious question, expecting some sensible responses, and
instead all I get are sarcastic comments.
No, you were trolling.

No, I was asking a serious question.

As reducing the noise floor (by whatever means) improves dynamics.
And this I have tested, I've recently been involved in cleaning up
some recordings made about 25 years ago on analogue equipment. This
process involves re-EQ followed by digital noise reduction, and the
results before and after applying the noise reduction are nothing
short of dramatic.
Cleaning up recordings most certainly does *not* involve eq. That
would be changing recordings.

By "cleaning up" I was referring specifically to applying digital noise
reduction. The re-EQ was mentioned simply for completeness, as the
recordings were a bit bass-shy and lacking in sparkle. So a touch of
smiley EQ solves that, followed by noise reduction.

It's rather vital that you EQ before NR though, otherwise the re-EQ
boosts bits that the NR has cut, leading to some interesting pumping
effects...

Read above - you can filter the mains til you turn blue and you won't
change your noise floor by even a milli dB.

On an average setup in an average domestic residence I'm sure that's the
case. Unfortunately I have a dozen or so PCs, all with switching power
supplies, sat in the next room, spewing RF onto the ring main. Which in
theory could be affecting the sound... at least in theory.

Turn your amplifier on, with no music playing and listen. Leave the
volume control in the normal listening position and sit in your
listening chair. What can you hear? Anything? Of course not. And what
little hiss there is comes from the front end of the amplifier. None
of it comes from the mains.

You can't hear much above 20kHz. But signals at frequencies above this
will affect what you do hear, harmonics, interaction etc. Why do you
think there's been so much work done on DVD-A, SACD etc, using sample
rates of 96kHz or even 192kHz, rather than 44.1?

Good old Russ Andrews - he has successfully conned £250 out of you.

Read my earlier postings. Currently I'm just using a standard IEC cable,
running into a surge protected (not even an RFI filtered) 4-way strip.
Surge protected for obvious reasons... I don't want a rogue power spike
frying 2 grand's worth of kit.

Now wise up and stop waving your stupidity like a flag of honour.

You are Stewart Pinkerton and I claim my five pounds.

That is the end of that then. You are not an engineer - you have never
been an engineer and you can never be an engineer.

So for goodness sake stop posting stuff that is trying to sound like
engineering when it is in fact unmitigated balls. I already told you,
it is no longer funny. Stick to whatever it is you know about.

d


Don. Have you taken your Andrew's liver salts this morning?
You are sounding like a grumpy old man:-)

It's a beautiful sunny day here. I am just off for a morning
walk down to the sea with the Airedale.

Regards to all.

Iain

Mains filters
 

On Thu, 16 Mar 2006 11:33:07 +0200, "Iain Churches"
wrote:


Don. Have you taken your Andrew's liver salts this morning?
You are sounding like a grumpy old man:-)

It's a beautiful sunny day here. I am just off for a morning
walk down to the sea with the Airedale.

Regards to all.

Iain


I am a grumpy old man - that is what keeps me so happy. Today it is
trying to snow, and I am about to go for a walk down to Sainsbury's to
get some food.

Just heard a thing on the radio about the London olympics in 2012, so
that is another excuse for me to snarl at people. Does anybody - apart
from those unmentionable lycra-wearers - give a flying stuff about the
Commonwealth Games? The opening ceremony was on telly last night, and
what little I saw was truly bizarre; definitely not to be switched on
during the next two weeks or whatever.

d

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

Mains filters
 

"Glenn Richards" wrote in message
...
Rich Wilson wrote:

If you're going to upgrade your power cable you really ought to do it
all the way back to the substation, otherwise it's a bit pointless...

Well that was my initial thought... but apparently not.

In a conversation I had with a friend, we determined that power cables are
good at carrying low frequencies, and poor at carrying higher frequencies.
So RFI picked up at the substation won't make it to your house, but
interference sources in your house will cause RFI to reach your kit.


That actually isn't true. Until recently, when the amateur radio community,
via first the R.A. and then Ofcom, managed to get it stopped, there were
tests of a system call PLT ( power line transmission ). This system placed
RF carriers up to about 30MHz, onto the domestic mains supply. The purpose
was for data transmission of the broadband internet variety. However, no
matter how balanced the mains supply is, it still isn't good enough to
prevent common mode currents at these sorts of frequencies, and therin lies
one of the major problems with this technology. The whole mains supply
network, from the injection point at the substation, to your house, has a
tendency to radiate like a dammed great antenna, at times causing serious
interference to legitimate receiving equipment - and thats not a hifi, it's
a radio.

It was eventually determined that there were better, more efficient, and
less troublesome technologies available for broadband delivery, and dropped,
at least here, although I believe that there may still be some places in
Europe where the tests are still happening. Bear in mind also, that the
generating and distribution companies, use this, or a similar high frequency
technology, in-house to carry telemetry data around their grid distribution
network. So, just to recap, the mains power distribution system can
successfully carry HF, as well as LF, all the way to your house.

As far as interference escaping from your equipment goes, it certainly
shouldn't, under strict EU regulations. Any electrical / electronic
equipment sold in the EU, should carry CE certification, and one of the
requirements of this certification, is that the equipment does not either
send crap out onto the mains, above a certain very low level, nor directly
radiate it. Further, the equipment's normal performance must not be
compromised in any way, by the presence of high level RF or pulse
interference, either introduced into any outside-world ports, the mains
supply being one such, or by direct radiation.

So again, to recap. If the equipment is reasonably recent, and the
manufacturer is playing by the rules, it should not feed any crap onto the
mains supply. If your hifi manufacturer has played by the rules, his kit
should not respond to any such crap, that got onto the mains by any route.

All that said, there's no harm at all in helping your kit out by fitting a
surge arrester plug, which contains VDRs, and if you find a good one, it
should have RF suppression in the form of LCR in it, as well. Worth a tenner
for the surge protection at least, and the ' belt and braces ' for the
filtering that should already be in your kit, but I certainly wouldn't pay
any more. Even then, I would probably spend the rest of the week trying to
work out if my money would have been better spent on 4 pints ...

Arfa

Mains filters
 

Arfa Daily wrote:

In a conversation I had with a friend, we determined that power
cables are good at carrying low frequencies, and poor at carrying
higher frequencies. So RFI picked up at the substation won't make
it to your house, but interference sources in your house will cause
RFI to reach your kit.
That actually isn't true. Until recently, when the amateur radio
community, via first the R.A. and then Ofcom, managed to get it
stopped, there were tests of a system call PLT ( power line
transmission ). This system placed RF carriers up to about 30MHz,
onto the domestic mains supply.

This technology actually exists (possibly at a different frequency), and
works very well.

About 18 months ago some student friends asked me if I could get
broadband around their shared house. First thoughts were WLAN of course,
so I duly ordered a broadband account for them, and set up a wireless
router in a central location, with wireless cards in all the PCs and
laptops allowing everyone to access the internet through it.

Unfortunately, it was a rather large house, and there was a huge dead
spot on the ground floor. So... enter HomePlug.

Whacked a HomePlug powerline networking bridge into the router via wired
Ethernet, and plugged a HomePlug access point in on the ground floor in
the middle of the dead spot. Which solved the problem.

All that said, there's no harm at all in helping your kit out by
fitting a surge arrester plug, which contains VDRs, and if you find a
good one, it should have RF suppression in the form of LCR in it, as
well. Worth a tenner for the surge protection at least, and the '
belt and braces ' for the filtering that should already be in your
kit, but I certainly wouldn't pay any more. Even then, I would
probably spend the rest of the week trying to work out if my money
would have been better spent on 4 pints ...

From a purely objective point of view, it's worth spending a tenner (of
a fiver trade) on a surge protected strip to protect 2 grand's worth of
kit, especially if you happen to live somewhere where there's dodgy
power. Yay rural areas...

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

IT consultancy, hardware and software support, broadband installation

Mains filters
 

It was eventually determined that there were better, more efficient, and
less troublesome technologies available for broadband delivery, and dropped,
at least here, although I believe that there may still be some places in
Europe where the tests are still happening. Bear in mind also, that the
generating and distribution companies, use this, or a similar high frequency
technology, in-house to carry telemetry data around their grid distribution
network.

What over the 475 kV grid?, don't you mean via the fibre optic at the
top running along the "aerial" earth wire?....

--
Tony Sayer

Mains filters
 

Don Pearce wrote:

So for goodness sake stop posting stuff that is trying to sound like
engineering when it is in fact unmitigated balls. I already told you,
it is no longer funny. Stick to whatever it is you know about.

So the bottom line is that you don't believe RFI filtering will make a
difference.

Why didn't you just say that? Why did you have to resort to posting all
that crap, in response to what was quite a serious question?

What really is no longer funny is that when one posts a question or
observation on this group that doesn't quite fit within the narrow
viewpoints of certain people that think they own and run this newsgroup,
all hell breaks loose, making it impossible to have a civilised
discussion about anything at all. Because there's always someone who
will disagree with subject "x" enough to start hurling personal insults
around.

If your opinion is that filtering won't make a difference, state your
opinion, avoid personal insults, and let civilised debate commence.

Sadly there doesn't appear to be a uk.rec.hi-fi where those of us who
can tell the difference between bell wire and 105-strand speaker cable
can have a discussion about which cable sounds best with which
equipment, without the likes of yourselves or Pinkerton (to name but
two) chiming in with "********" or words to that effect. We've got
uk.rec.audio.vinyl now, why not have uk.rec.audio.hi-fi or audiophile as
well?

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

IT consultancy, hardware and software support, broadband installation

Mains filters
 

"Iain Churches" wrote in message
...

"Don Pearce" wrote in message
...
On Thu, 16 Mar 2006 10:39:13 +0200, "Iain Churches"
wrote:


Hi Don. I have a feeling you are right. In many years of large
recording sessions, with hundreds of cables and interconnects
I have never seen a mains filter unit in use.

A lot of Pro equipment includes a mains filter as part of the IEC mains
socket. I have VDRs fitted to the plugs feeding all my audio and computer
equipment, as I've found it helps reduce the number of unexplained lock-ups,
when only a power cycle will unlock the kit. I only get one or two a year
now, as opposed to one or two a month without them. I do live out in the
sticks, so my supply may well have less urban hash on it, but possibly more
surges.


S.

Mains filters
 

Don Pearce wrote:

Not while you are posting, it wouldn't. Stop now and lower the noise
floor by 20dB.

Pinkerton? Is that you? :-P

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

IT consultancy, hardware and software support, broadband installation

Mains filters
 

In article , Glenn Richards wrote:
In a conversation I had with a friend, we determined that power cables
are good at carrying low frequencies, and poor at carrying higher
frequencies. So RFI picked up at the substation won't make it to your
house, but interference sources in your house will cause RFI to reach
your kit.

How do you determine the electrical properties of cables by conversation?

Rod.

Mains filters
 

In article , Glenn Richards wrote:
I've figured out a method of constructing a filtered power cable for
less than £10 materials cost, depending on quantity. Which, if the hi-fi
mags are anything to go by, will sell for anything up to £60.

And if it does make a perceptible difference, however tiny, that means
£50 profit each time...

And when it is discovered that it makes no difference whatsoever...?

Rod.