Tuner memory
 

In article ,
Keith G wrote:
Even leaving items like projectors plugged in can cost you a 200+ quid
lamp - had a ten minute power cut here the other night (according to
some of the clocks) and the next evening the PJ was dead.....

Did the power coming back on switch on the projector? My DLP set will
react to any suddenly active video input by switching out of standby. But
not if it's switched off - rather than unplugged.

--
*Generally speaking, you aren't learning much if your lips are moving.*

Dave Plowman London SW
To e-mail, change noise into sound.

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Don Pearce wrote:
On Mon, 21 Aug 2006 08:33:26 +0100, Rob
wrote:

Don Pearce wrote:
On Sun, 20 Aug 2006 22:38:31 +0100, Rob
wrote:

Um - per means 'for each', unless you have a more accurate definition.
You told me to use 'for', or 'FOR', in the first place. Each means every
one of more. Don't mean to patronise ...
Per means divided by. The sum you are doing is multiplied by. You are
talking Watt Hours, not Watts per hour.

d

I meant 'per' in the context of 'for each' - wasn't that clear to you? I
hope you're not a maths or English teacher - would you really say 'six
per three equals two'?

Rob

"For each" is exactly the meaning of per, and that is why you have it
wrong. Suppose you buy 10 apples for 30 pence, that is three pence per
apple (for each). You do that sum by dividing 30 by ten. So Watts per
hour is Watts divided by hours. You need Watts MULTIPLIED by hours,
which is Watt Hours.

I'm not being pedantic - you are not just a little bit wrong, you have
it entirely upside down.

d


Well, I meant multiplied, but you've taken the word 'per' to mean
'divided' which I think you're always going to have difficulty
explaining to me - but thanks for trying. It's curious that you think
that I don't know the difference between multiply and divide - I do by
the way, picked that one up.

The point, that I should have expressed consumption as kWh, and not
watts per hour, is taken. Am I allowed to use the term Wh' BTW?

Rob

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Jim Lesurf wrote:
In article , Rob
wrote:


Er, it was! Have I misunderstood something - wouldn't be the first/last
time :-)

I mean he consumes 400 Watts of electricity in one hour. Stand corrected
awaits ...

The nominal unit of energy is the Joule.

Power is the *rate* of energy transfer/creation/loss.

1 Watt (power) is 1 Joule per second (energy per time period).

Thus saying "watts per hour" implies "1 Joule per second, per hour", which
may be gibberish as it is neither a power nor an energy.

Thus the Watt-hour is also a unit of energy since it is the number of
joules transferred/created/used if you use power at the rate of 1 joule per
second for 1 hour. The common unit is the kWh.

Hence it isn't clear what something like, "he consumes 400 Watts of
electricity in one hour" actually means.


I think if forced, under considerable duress and on pain of death, you
could (on a good day) guess what was meant :-)

Am I allowed to say Wh - would that be ambiguous?

Rob

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On Mon, 21 Aug 2006 13:36:20 +0100, Rob
wrote:

Don Pearce wrote:
On Mon, 21 Aug 2006 08:33:26 +0100, Rob
wrote:

Don Pearce wrote:
On Sun, 20 Aug 2006 22:38:31 +0100, Rob
wrote:

Um - per means 'for each', unless you have a more accurate definition.
You told me to use 'for', or 'FOR', in the first place. Each means every
one of more. Don't mean to patronise ...
Per means divided by. The sum you are doing is multiplied by. You are
talking Watt Hours, not Watts per hour.

d

I meant 'per' in the context of 'for each' - wasn't that clear to you? I
hope you're not a maths or English teacher - would you really say 'six
per three equals two'?

Rob

"For each" is exactly the meaning of per, and that is why you have it
wrong. Suppose you buy 10 apples for 30 pence, that is three pence per
apple (for each). You do that sum by dividing 30 by ten. So Watts per
hour is Watts divided by hours. You need Watts MULTIPLIED by hours,
which is Watt Hours.

I'm not being pedantic - you are not just a little bit wrong, you have
it entirely upside down.

d


Well, I meant multiplied, but you've taken the word 'per' to mean
'divided' which I think you're always going to have difficulty
explaining to me - but thanks for trying. It's curious that you think
that I don't know the difference between multiply and divide - I do by
the way, picked that one up.


No, I didn't think you couldn't tell the difference between divide and
multiply. I thought you didn't understand the mathematical meaning of
the word "per". Such has proved to be the case.

The point, that I should have expressed consumption as kWh, and not
watts per hour, is taken. Am I allowed to use the term Wh' BTW?

Wh is just fine.

d

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

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On Mon, 21 Aug 2006 13:42:31 +0100, Rob
wrote:

Hence it isn't clear what something like, "he consumes 400 Watts of
electricity in one hour" actually means.


I think if forced, under considerable duress and on pain of death, you
could (on a good day) guess what was meant :-)

The problem with saying you consume 400W of electricity in one hour is
that there is instantly a corollary, which it that you will thus
consume 800W in two hours, and so on. Do you see the problem?

d

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

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In article ,
Rob wrote:
Jim Lesurf wrote:
[snip]

I think if forced, under considerable duress and on pain of death, you
could (on a good day) guess what was meant :-)

Are you unclear on the distinction between 'energy' and 'power'? If so,
then the units used may well confuse.

Am I allowed to say Wh - would that be ambiguous?

For what? :-)

If you mean 'Wh' to mean 'Watt-hour' then this is a unit of energy. It
represents the energy conveyed/used if you consume power at the rate of 1
Watt, for a duration of 1 hour.

So if you have a light bulb rated at '100W' it will use up 1 kWh if you
leave it on for 10 hours. You then pay for energy (numbered in an amount of
kWh). A 50W light would have to be on for 20 hourse to use up 1kWh of
energy.

Also, imagine you have two immersion heaters. One 1 kW, the other 2 kW.

With perfect insulation, the 2kW heater will heat up a tank of water in
half the time that the 1kW heater will require to get the same rise in
temperature. But the amount of energy used will be the same whichever you
used. (In the real world, the insulation won't be perfect, so it won't be
that simple. However physicists are allowed to do things like ignore all
such annoying complications when trying to explain something. :-) )

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

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Jim Lesurf wrote:
In article ,
Rob wrote:
Jim Lesurf wrote:
[snip]

I think if forced, under considerable duress and on pain of death, you
could (on a good day) guess what was meant :-)

Are you unclear on the distinction between 'energy' and 'power'? If so,
then the units used may well confuse.


Well, energy is power; power is the exercise of will :-)

Am I allowed to say Wh - would that be ambiguous?

For what? :-)


Just as a unit of energy, no more, nothing flash.

If you mean 'Wh' to mean 'Watt-hour' then this is a unit of energy. It
represents the energy conveyed/used if you consume power at the rate of 1
Watt, for a duration of 1 hour.

So if you have a light bulb rated at '100W' it will use up 1 kWh if you
leave it on for 10 hours. You then pay for energy (numbered in an amount of
kWh). A 50W light would have to be on for 20 hourse to use up 1kWh of
energy.

Also, imagine you have two immersion heaters. One 1 kW, the other 2 kW.

With perfect insulation, the 2kW heater will heat up a tank of water in
half the time that the 1kW heater will require to get the same rise in
temperature. But the amount of energy used will be the same whichever you
used. (In the real world, the insulation won't be perfect, so it won't be
that simple. However physicists are allowed to do things like ignore all
such annoying complications when trying to explain something. :-) )


Yes, many thanks - I worked on HEES for a couple of years so I am
familiar with what you're saying. That was more to do with fuel poverty
though - not nomenclature. You've all certainly driven home the
importance of precision here so I won't be using the phrase 'Watts per
hour' when I mean Wh.

Phew :-)

Rob

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Don Pearce wrote:
On Mon, 21 Aug 2006 13:42:31 +0100, Rob
wrote:

Hence it isn't clear what something like, "he consumes 400 Watts of
electricity in one hour" actually means.

I think if forced, under considerable duress and on pain of death, you
could (on a good day) guess what was meant :-)

The problem with saying you consume 400W of electricity in one hour is
that there is instantly a corollary, which it that you will thus
consume 800W in two hours, and so on. Do you see the problem?

d


Yes, that's quite clear, thanks Don.

Now, on pain of death I take it your answer to the question "If you had
to guess, if someone used the phrase 'Watts per hour', what do you think
they meant?" is:

---

The problem with saying you consume 400W of electricity in one hour is
that there is instantly a corollary, which it that you will thus consume
800W in two hours, and so on. Do you see the problem?

---

In other words, you have absolutely no idea - not even a remote clue, it
would never occur to you that Wh is the answer.

Blimey :-)

Tuner memory
 

On Mon, 21 Aug 2006 18:08:19 +0100, Rob
wrote:

Yes, that's quite clear, thanks Don.

Now, on pain of death I take it your answer to the question "If you had
to guess, if someone used the phrase 'Watts per hour', what do you think
they meant?" is:

I wouldn't have the slightest idea. I would have to assume that they
hadn't either.

---

The problem with saying you consume 400W of electricity in one hour is
that there is instantly a corollary, which it that you will thus consume
800W in two hours, and so on. Do you see the problem?

---

In other words, you have absolutely no idea - not even a remote clue, it
would never occur to you that Wh is the answer.

Blimey :-)

Not really. As I said above, if somebody gave a figure in Watts per
hour, and particularly if they persisted in doing so in the face of
multiple questions, I would assume they had not the slightest clue,
and the figure was therefore devoid of meaning.

Before anyone gets picky, there is of course a circumstance in which
the figure would make sense. It would be if they were talking about a
power generator that was ramping its power upwards at a rate of 400
watts per hour. I take it you don't have such a machine in mind?

d

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

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On Mon, 21 Aug 2006 18:02:15 +0100, Rob
wrote:

Jim Lesurf wrote:
In article ,
Rob wrote:
Jim Lesurf wrote:
[snip]

I think if forced, under considerable duress and on pain of death, you
could (on a good day) guess what was meant :-)

Are you unclear on the distinction between 'energy' and 'power'? If so,
then the units used may well confuse.


Well, energy is power; power is the exercise of will :-)

Now now. Power is the rate at which energy is delivered. :-)

d

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

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On Mon, 21 Aug 2006 13:42:31 +0100, Rob
wrote:

I think if forced, under considerable duress and on pain of death, you
could (on a good day) guess what was meant :-)

Am I allowed to say Wh - would that be ambiguous?

wH are fine, though KwH are more usual.

Tuner memory
 

In article ,
Rob wrote:
One of the few (obviously!) things I remember from physics at school is
that you should use the appliance switch if it has one to avoid damage,
rather than the socket switch or pull the plug. Is there any truth to
this?

I take it your physics teacher had a degree in physical education? Because
it's basically rubbish. Although some devices like projectors have cooling
fans which are meant to run after powering down, but I'll bet he wasn't
thinking of those.

--
*The longest recorded flightof a chicken is thirteen seconds *

Dave Plowman London SW
To e-mail, change noise into sound.

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"Don Pearce" wrote in message
...
On Mon, 21 Aug 2006 08:40:31 +0100, Rob
wrote:



One of the few (obviously!) things I remember from physics at school is
that you should use the appliance switch if it has one to avoid damage,
rather than the socket switch or pull the plug. Is there any truth to
this?

Rob

It depends. If the appliance switch is simply turning off the incoming
mains (the traditional way to do it), then pulling the plug or
switching off at the socket is exactly equivalent. If the appliance
switch works through some electronic function, then it isn't.

But whatever the case, there should be absolutely no danger of damage.


???

You never seen a wall socket with one hole a bit bigger than the other, with
blackened edges....???

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On Tue, 22 Aug 2006 00:22:20 +0100, "Keith G"
wrote:


"Don Pearce" wrote in message
...
On Mon, 21 Aug 2006 08:40:31 +0100, Rob
wrote:



One of the few (obviously!) things I remember from physics at school is
that you should use the appliance switch if it has one to avoid damage,
rather than the socket switch or pull the plug. Is there any truth to
this?

Rob

It depends. If the appliance switch is simply turning off the incoming
mains (the traditional way to do it), then pulling the plug or
switching off at the socket is exactly equivalent. If the appliance
switch works through some electronic function, then it isn't.

But whatever the case, there should be absolutely no danger of damage.


???

You never seen a wall socket with one hole a bit bigger than the other, with
blackened edges....???



Errrrmmmm..... No.

d

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

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Don Pearce wrote:
On Mon, 21 Aug 2006 08:40:31 +0100, Rob
wrote:

Trevor Wilson wrote:
"Serge Auckland" wrote in message
...
I would suggest that our domestic consumption is typical, even lower than
average as our children have left home, so if more people turned off stuff
on standby, the power saving would be very considerable. There is the
anecdotal evidence that equipment left on standby or permanently on seems
to be more reliable, but I'm happy to take that chance.
**A common misconception. The killer for most permanently powered items are
capacitor failures. Turning stuff off and on as required does several
things:

* Capacitors last longer.
* The product is shielded from unnecessary spikes on the mains.

I always turn stuff off (except for the obvious stuff, with clocks) unless I
actually want to use it.

One of the few (obviously!) things I remember from physics at school is
that you should use the appliance switch if it has one to avoid damage,
rather than the socket switch or pull the plug. Is there any truth to this?

Rob

It depends. If the appliance switch is simply turning off the incoming
mains (the traditional way to do it), then pulling the plug or
switching off at the socket is exactly equivalent. If the appliance
switch works through some electronic function, then it isn't.

But whatever the case, there should be absolutely no danger of damage.

d


That's grand - thanks.

Rob

Tuner memory
 

Dave Plowman (News) wrote:
In article ,
Rob wrote:
One of the few (obviously!) things I remember from physics at school is
that you should use the appliance switch if it has one to avoid damage,
rather than the socket switch or pull the plug. Is there any truth to
this?

I take it your physics teacher had a degree in physical education? Because
it's basically rubbish. Although some devices like projectors have cooling
fans which are meant to run after powering down, but I'll bet he wasn't
thinking of those.


No, she (it was a 'she', Dave, and not a 'he' - Ms Lyons, class 3C, BVGS
Birmingham 1976) was/is a physics graduate although she didn't have a
PhD - or at least she didn't use the title 'Dr' (most of the other
staff did). I'm afraid I can't remember if she was a member of any
chartered or similar organisation - sorry.

I was trying to remember last night - I asked her 'why?', and I'm pretty
sure the answer had the word 'surge' in it, and tailed off into a 'this
doesn't apply to everything but as a rule you shouldn't switch a
switched device on or off at the mains. Device first, mains second'. I
tried it with my system - 3 valve amps, TT and CD, and left them
switched on at the appliance and just flip the switch at the mains.
Mighty convenience, but hell of a thump at the speakers when it's
switched on, fine when switched off.

Rob

Tuner memory
 

In article ,
Rob wrote:
I take it your physics teacher had a degree in physical education? Because
it's basically rubbish. Although some devices like projectors have cooling
fans which are meant to run after powering down, but I'll bet he wasn't
thinking of those.


No, she (it was a 'she', Dave, and not a 'he' - Ms Lyons, class 3C, BVGS
Birmingham 1976) was/is a physics graduate although she didn't have a
PhD - or at least she didn't use the title 'Dr' (most of the other
staff did). I'm afraid I can't remember if she was a member of any
chartered or similar organisation - sorry.

I was trying to remember last night - I asked her 'why?', and I'm pretty
sure the answer had the word 'surge' in it, and tailed off into a 'this
doesn't apply to everything but as a rule you shouldn't switch a
switched device on or off at the mains. Device first, mains second'. I
tried it with my system - 3 valve amps, TT and CD, and left them
switched on at the appliance and just flip the switch at the mains.
Mighty convenience, but hell of a thump at the speakers when it's
switched on, fine when switched off.

That's rather different as there's no way you could switch all the devices
simultaneously except at the socket.

But I'd be worried if a valve power amp produced a thump at the speakers
when powered up.

--
*60-year-old, one owner - needs parts, make offer

Dave Plowman London SW
To e-mail, change noise into sound.

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"Don Pearce" wrote in message
...
On Tue, 22 Aug 2006 00:22:20 +0100, "Keith G"
wrote:


"Don Pearce" wrote in message
...
On Mon, 21 Aug 2006 08:40:31 +0100, Rob
wrote:



One of the few (obviously!) things I remember from physics at school is
that you should use the appliance switch if it has one to avoid damage,
rather than the socket switch or pull the plug. Is there any truth to
this?

Rob

It depends. If the appliance switch is simply turning off the incoming
mains (the traditional way to do it), then pulling the plug or
switching off at the socket is exactly equivalent. If the appliance
switch works through some electronic function, then it isn't.

But whatever the case, there should be absolutely no danger of damage.


???

You never seen a wall socket with one hole a bit bigger than the other,
with
blackened edges....???



Errrrmmmm..... No.



Errrrmmmm..... Really?

I have on a number of occasions.

How about seeing a flash when pulling a plug out? (Like even through the
white plastic?)

Tuner memory
 

"Rob" wrote in message
...
Don Pearce wrote:
On Mon, 21 Aug 2006 08:40:31 +0100, Rob
wrote:

Trevor Wilson wrote:
"Serge Auckland" wrote in message
...
I would suggest that our domestic consumption is typical, even lower
than average as our children have left home, so if more people turned
off stuff on standby, the power saving would be very considerable.
There is the anecdotal evidence that equipment left on standby or
permanently on seems to be more reliable, but I'm happy to take that
chance.
**A common misconception. The killer for most permanently powered items
are capacitor failures. Turning stuff off and on as required does
several things:

* Capacitors last longer.
* The product is shielded from unnecessary spikes on the mains.

I always turn stuff off (except for the obvious stuff, with clocks)
unless I actually want to use it.

One of the few (obviously!) things I remember from physics at school is
that you should use the appliance switch if it has one to avoid damage,
rather than the socket switch or pull the plug. Is there any truth to
this?

Rob

It depends. If the appliance switch is simply turning off the incoming
mains (the traditional way to do it), then pulling the plug or
switching off at the socket is exactly equivalent. If the appliance
switch works through some electronic function, then it isn't.

But whatever the case, there should be absolutely no danger of damage.

d


That's grand - thanks.


Except that it's not (see my posts alluding to burnt sockets).......

Also, do not be tempted to plug in a 'kettle lead' with the mains end
already plgged in - I've done that many times in the past, but had a little
'pop and flutter', once or twice recently.....

Tuner memory
 

On Tue, 22 Aug 2006 11:13:57 +0100, "Keith G"
wrote:


"Don Pearce" wrote in message
...
On Tue, 22 Aug 2006 00:22:20 +0100, "Keith G"
wrote:


"Don Pearce" wrote in message
.. .
On Mon, 21 Aug 2006 08:40:31 +0100, Rob
wrote:



One of the few (obviously!) things I remember from physics at school is
that you should use the appliance switch if it has one to avoid damage,
rather than the socket switch or pull the plug. Is there any truth to
this?

Rob

It depends. If the appliance switch is simply turning off the incoming
mains (the traditional way to do it), then pulling the plug or
switching off at the socket is exactly equivalent. If the appliance
switch works through some electronic function, then it isn't.

But whatever the case, there should be absolutely no danger of damage.


???

You never seen a wall socket with one hole a bit bigger than the other,
with
blackened edges....???



Errrrmmmm..... No.



Errrrmmmm..... Really?

I have on a number of occasions.

How about seeing a flash when pulling a plug out? (Like even through the
white plastic?)


Maybe when unplugging something really meaty - but never anything like
a Hi Fi.

d

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

Tuner memory
 

"Don Pearce" wrote in message
...
On Tue, 22 Aug 2006 11:13:57 +0100, "Keith G"
wrote:


"Don Pearce" wrote in message
.. .
On Tue, 22 Aug 2006 00:22:20 +0100, "Keith G"
wrote:


"Don Pearce" wrote in message
. ..
On Mon, 21 Aug 2006 08:40:31 +0100, Rob
wrote:



One of the few (obviously!) things I remember from physics at school
is
that you should use the appliance switch if it has one to avoid
damage,
rather than the socket switch or pull the plug. Is there any truth to
this?

Rob

It depends. If the appliance switch is simply turning off the incoming
mains (the traditional way to do it), then pulling the plug or
switching off at the socket is exactly equivalent. If the appliance
switch works through some electronic function, then it isn't.

But whatever the case, there should be absolutely no danger of damage.


???

You never seen a wall socket with one hole a bit bigger than the other,
with
blackened edges....???



Errrrmmmm..... No.



Errrrmmmm..... Really?

I have on a number of occasions.

How about seeing a flash when pulling a plug out? (Like even through the
white plastic?)


Maybe when unplugging something really meaty - but never anything like
a Hi Fi.


I did a projector swap the other evening using the same kettle lead that was
already plugged in and got a little 'plip' as I plugged the thin end into
the PJ - thus, I suspect, nearly reducing myself to *two* frazzled PJs at a
stroke!! I have no idea how many times I've heard fizzing/pops/cracks
pulling plugs out (audio gear) over the years - usually because I was in an
awkward position and not able to do it quickly and cleanly....

Tuner memory
 

On Tue, 22 Aug 2006 12:43:41 +0100, "Keith G"
wrote:

I did a projector swap the other evening using the same kettle lead that was
already plugged in and got a little 'plip' as I plugged the thin end into
the PJ - thus, I suspect, nearly reducing myself to *two* frazzled PJs at a
stroke!!

Why do you suspect that?

Tuner memory
 

"Laurence Payne" lpayne1NOSPAM@dslDOTpipexDOTcom wrote in message
...
On Tue, 22 Aug 2006 12:43:41 +0100, "Keith G"
wrote:

I did a projector swap the other evening using the same kettle lead that
was
already plugged in and got a little 'plip' as I plugged the thin end into
the PJ - thus, I suspect, nearly reducing myself to *two* frazzled PJs at
a
stroke!!

Why do you suspect that?



Because the PJ I wuz swapping out had (apparently) been rendered dead by a
10 minute power cut the night before and there I was, zapping the second
one....

(The first PJ *is* rendered dead by a blown lamp - sez so in the manual...)

Tuner memory
 

Dave Plowman (News) wrote:
In article ,
Rob wrote:
I take it your physics teacher had a degree in physical education? Because
it's basically rubbish. Although some devices like projectors have cooling
fans which are meant to run after powering down, but I'll bet he wasn't
thinking of those.


No, she (it was a 'she', Dave, and not a 'he' - Ms Lyons, class 3C, BVGS
Birmingham 1976) was/is a physics graduate although she didn't have a
PhD - or at least she didn't use the title 'Dr' (most of the other
staff did). I'm afraid I can't remember if she was a member of any
chartered or similar organisation - sorry.

I was trying to remember last night - I asked her 'why?', and I'm pretty
sure the answer had the word 'surge' in it, and tailed off into a 'this
doesn't apply to everything but as a rule you shouldn't switch a
switched device on or off at the mains. Device first, mains second'. I
tried it with my system - 3 valve amps, TT and CD, and left them
switched on at the appliance and just flip the switch at the mains.
Mighty convenience, but hell of a thump at the speakers when it's
switched on, fine when switched off.

That's rather different as there's no way you could switch all the devices
simultaneously except at the socket.


Indeed - it would be tricky - 6 switches!

But I'd be worried if a valve power amp produced a thump at the speakers
when powered up.


No, that's the curious thing - just a little 'blip' when the main supply
is switched in/on at the appliance. I'm not sure of the reason when
they're all put on at once, although I could easily isolate the rogue. I
have a feeling it is the power amp though - the guy who serviced it said
it's best to switch on the standby first, wait a minute, then switch on
the main thing.

The worst offender on the switch on thump syndrome is the CD - a
throoughly modern Marantz. I tend to switch that on first, followed by
everything else, finsihing with the power amp.

Rob

Tuner memory
 

Keith G wrote:
"Rob" wrote in message
...
Don Pearce wrote:
On Mon, 21 Aug 2006 08:40:31 +0100, Rob
wrote:

Trevor Wilson wrote:
"Serge Auckland" wrote in message
...
I would suggest that our domestic consumption is typical, even lower
than average as our children have left home, so if more people turned
off stuff on standby, the power saving would be very considerable.
There is the anecdotal evidence that equipment left on standby or
permanently on seems to be more reliable, but I'm happy to take that
chance.
**A common misconception. The killer for most permanently powered items
are capacitor failures. Turning stuff off and on as required does
several things:

* Capacitors last longer.
* The product is shielded from unnecessary spikes on the mains.

I always turn stuff off (except for the obvious stuff, with clocks)
unless I actually want to use it.

One of the few (obviously!) things I remember from physics at school is
that you should use the appliance switch if it has one to avoid damage,
rather than the socket switch or pull the plug. Is there any truth to
this?

Rob
It depends. If the appliance switch is simply turning off the incoming
mains (the traditional way to do it), then pulling the plug or
switching off at the socket is exactly equivalent. If the appliance
switch works through some electronic function, then it isn't.

But whatever the case, there should be absolutely no danger of damage.

d

That's grand - thanks.


Except that it's not (see my posts alluding to burnt sockets).......

Also, do not be tempted to plug in a 'kettle lead' with the mains end
already plgged in - I've done that many times in the past, but had a little
'pop and flutter', once or twice recently.....


Well, yep - it's a bit tricky having being told there's no danger of
damage, but I'll stick to my old habits of appliance first, mains second
for the pure and simple reason that I paid for the switches so I'm
bloody well going to use them :-)

Rob

Tuner memory
 

On Tue, 22 Aug 2006 14:17:01 +0100, Rob
wrote:

Dave Plowman (News) wrote:
In article ,
Rob wrote:
I take it your physics teacher had a degree in physical education? Because
it's basically rubbish. Although some devices like projectors have cooling
fans which are meant to run after powering down, but I'll bet he wasn't
thinking of those.


No, she (it was a 'she', Dave, and not a 'he' - Ms Lyons, class 3C, BVGS
Birmingham 1976) was/is a physics graduate although she didn't have a
PhD - or at least she didn't use the title 'Dr' (most of the other
staff did). I'm afraid I can't remember if she was a member of any
chartered or similar organisation - sorry.

I was trying to remember last night - I asked her 'why?', and I'm pretty
sure the answer had the word 'surge' in it, and tailed off into a 'this
doesn't apply to everything but as a rule you shouldn't switch a
switched device on or off at the mains. Device first, mains second'. I
tried it with my system - 3 valve amps, TT and CD, and left them
switched on at the appliance and just flip the switch at the mains.
Mighty convenience, but hell of a thump at the speakers when it's
switched on, fine when switched off.

That's rather different as there's no way you could switch all the devices
simultaneously except at the socket.


Indeed - it would be tricky - 6 switches!

But I'd be worried if a valve power amp produced a thump at the speakers
when powered up.


No, that's the curious thing - just a little 'blip' when the main supply
is switched in/on at the appliance. I'm not sure of the reason when
they're all put on at once, although I could easily isolate the rogue. I
have a feeling it is the power amp though - the guy who serviced it said
it's best to switch on the standby first, wait a minute, then switch on
the main thing.

Are you sure? The usual way is main first, then standby later.
Switching on the standby first does nothing until the main is on.


The worst offender on the switch on thump syndrome is the CD - a
throoughly modern Marantz. I tend to switch that on first, followed by
everything else, finsihing with the power amp.

Rob

It sounds like the amp is the common factor here, and thus also the
problem.

d

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

Tuner memory
 

Don Pearce wrote:
On Tue, 22 Aug 2006 14:17:01 +0100, Rob
wrote:

Dave Plowman (News) wrote:
In article ,
Rob wrote:
I take it your physics teacher had a degree in physical education? Because
it's basically rubbish. Although some devices like projectors have cooling
fans which are meant to run after powering down, but I'll bet he wasn't
thinking of those.

No, she (it was a 'she', Dave, and not a 'he' - Ms Lyons, class 3C, BVGS
Birmingham 1976) was/is a physics graduate although she didn't have a
PhD - or at least she didn't use the title 'Dr' (most of the other
staff did). I'm afraid I can't remember if she was a member of any
chartered or similar organisation - sorry.
I was trying to remember last night - I asked her 'why?', and I'm pretty
sure the answer had the word 'surge' in it, and tailed off into a 'this
doesn't apply to everything but as a rule you shouldn't switch a
switched device on or off at the mains. Device first, mains second'. I
tried it with my system - 3 valve amps, TT and CD, and left them
switched on at the appliance and just flip the switch at the mains.
Mighty convenience, but hell of a thump at the speakers when it's
switched on, fine when switched off.
That's rather different as there's no way you could switch all the devices
simultaneously except at the socket.

Indeed - it would be tricky - 6 switches!

But I'd be worried if a valve power amp produced a thump at the speakers
when powered up.

No, that's the curious thing - just a little 'blip' when the main supply
is switched in/on at the appliance. I'm not sure of the reason when
they're all put on at once, although I could easily isolate the rogue. I
have a feeling it is the power amp though - the guy who serviced it said
it's best to switch on the standby first, wait a minute, then switch on
the main thing.

Are you sure? The usual way is main first, then standby later.
Switching on the standby first does nothing until the main is on.


Yes, I'm sure. It's a Beard P100. The amp was originally fitted with a
'soft start', that would actually amplify, albeit at low volumes. The
problem was that owners kept them in this 'standby' mode all the time,
and early valve failure was common. Mine has been rewired so that
standby does something (all the valves light up but no sound), and power
brings with it sound.

The worst offender on the switch on thump syndrome is the CD - a
throoughly modern Marantz. I tend to switch that on first, followed by
everything else, finsihing with the power amp.

Rob

It sounds like the amp is the common factor here, and thus also the
problem.


Yes, I think it is the amp, but if the only way is to follow the
suggested power-up routine, then life goes on.

Rob

Tuner memory
 

"Rob" wrote


seven indents is too much for me....


Except that it's not (see my posts alluding to burnt sockets).......

Also, do not be tempted to plug in a 'kettle lead' with the mains end
already plgged in - I've done that many times in the past, but had a
little 'pop and flutter', once or twice recently.....


Well, yep - it's a bit tricky having being told there's no danger of
damage, but I'll stick to my old habits of appliance first, mains second
for the pure and simple reason that I paid for the switches so I'm bloody
well going to use them :-)


There used to be a saying that you switched the kit on like the amp was the
MD - last in and first out. Having been one for over a decade (MD that is,
not amp...) you can take if from me that that is exactly the wrong way
round!

.....A good MD gives 'em time in the morning to correct the cock-ups made the
previous day 'unnoticed' before he arrives and stays on long enough in the
evening to discover what cock-up there will need to be surreptitiously (and
swiftly) corrected before he arrives the next morning!! ;-)

Tuner memory
 

And to think all I did was ask about a tuner that doesn't forget when
the mains is off!


I built a 100Wpc dual-mono MOSFET power amp and wanted to switch it
from the pre-amp - at the time a Quad 33. I got a 30A solid state
relay, fitted it inside the amp, and switched it from the low voltage
supply from the pre-amp. Never had any thump or anything like.

The reason? Solid state relays only switch on at the zero crossing of
the mains, so there can never be any inrush current per se......


--
Woody

harrogate3 at ntlworld dot com

Tuner memory
 

In article ,
harrogate3 wrote:
I built a 100Wpc dual-mono MOSFET power amp and wanted to switch it
from the pre-amp - at the time a Quad 33. I got a 30A solid state
relay, fitted it inside the amp, and switched it from the low voltage
supply from the pre-amp. Never had any thump or anything like.

The reason? Solid state relays only switch on at the zero crossing of
the mains, so there can never be any inrush current per se......

I sincerely hope the 'mains inrush current' doesn't get to the speakers on
any amp...

--
*We are born naked, wet, and hungry. Then things get worse.

Dave Plowman London SW
To e-mail, change noise into sound.

Tuner memory
 

In article , harrogate3
wrote:
And to think all I did was ask about a tuner that doesn't forget when
the mains is off!


I built a 100Wpc dual-mono MOSFET power amp and wanted to switch it from
the pre-amp - at the time a Quad 33. I got a 30A solid state relay,
fitted it inside the amp, and switched it from the low voltage supply
from the pre-amp. Never had any thump or anything like.

The reason? Solid state relays only switch on at the zero crossing of
the mains, so there can never be any inrush current per se......


Oh yes there can. :-)

The first quarter cycle might still have to change the reservoir caps. Thus
can easily produce a surge. It may well be much smaller than if you'd
switched on at a mains peak, but the current at switch on may well be much
bigger than the current in normal use.

--
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