According to What Hi-Fi - more music. That simple.

I'm inclined to agree.

Discuss.

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

IT consultancy, hardware and software support, broadband installation

"Glenn Richards"

According to What Hi-Fi - more music. That simple.


** It would indeed be wonderful if you could *actually* buy music to play
through your home hi-fi.

Unfortunately, all you can ever purchase is another flawed commercial
recording.


I'm inclined to agree.


** Shame you are a ****wit TROLL.




....... Phil

"Phil Allison" wrote in message
...
::
:
: ** Shame you are a f***wit TROLL.
:
:
:
:
: ...... Philthy the Troll
:
:
Pot - Kettle - Toaster - Black, AGAIN!!!!!!!!!

TT

"Glenn Richards" wrote in message
...
According to What Hi-Fi - more music. That simple.

I'm inclined to agree.

Discuss.

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

IT consultancy, hardware and software support, broadband installation

My late wife's stepfather, W Cutler of Wolverhampton, read in some mentally
deranged hifi magazine that you should always keep the system switched on,
so now the ****** leave it on loud all night and keeps people awake. If I
was his neighbour, I would have made sure that Cutler was given an
anti-social behaviour order (ASBO) and had his hifi confiscated.
Regards Mike.

Mike Cawood, HND BIT wrote:

My late wife's stepfather, W Cutler of Wolverhampton, read in some
mentally deranged hifi magazine that you should always keep the
system switched on, so now the ****** leave it on loud all night and
keeps people awake. If I was his neighbour, I would have made sure
that Cutler was given an anti-social behaviour order (ASBO) and had
his hifi confiscated.

Yes... when hi-fi magazines talk about leaving the system switched on
permanently... I don't think that's *quite* what they meant!

Actually there's a lot to be said for leaving your kit on all the time
(if you're using it for more than say 8 hours in a day)... it eliminates
the "thermal cycling" effect. No, this is nothing to do with snake oil
or esoteric audiophile theories. If you heat metal up to 40-50 degrees
it expands, cool it back down to 18-20 degrees (normal room temperature)
it'll contract. Enough cycles and it'll fracture.

Also it avoids the surge current when you power it up. Think light bulbs
- they nearly always fail when you turn the power on. A sudden inrush
current into a cold filament causes a thermal shock. As an aside, the
bulbs for my wall lights in my living room are quite expensive, so I've
wired them through a 'soft switch' which fades them up to full
brightness when you turn them on and fades down to dark when you turn
them off. Practical advantage is that it avoids thermal shock to the
bulbs... and it looks *really* cool!

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

IT consultancy, hardware and software support, broadband installation

There is good reason to leave a system on so as to not excessivly
power cycle it. And then we apply numbers. Amazing how numbers expose
junk science reasoning. For example, power switch is typically rated
for 100,000 cycle: seven times every day of the year for .... 39
years. IOW worry about something that is totally irrelevant.

These decrees about power cycling (thermal cycling) as destructive
are chock full of technical ignorance, no numbers, and even forgets
that normal operation is also power cycling and thermal cycling.

Semiconductors are manufactured in repeated cycles from room
temperature to upwards of 900 degrees. Now that is real thermal
cycling - and it is not destructive. Do same items get thermal cycled
when temperature varies less than 100 degree? Of course not. Yes
thermal cycling is destructive. And again we apply numbers. After how
many generations? When doing it seven times every day - including
holidays and vacation? Junk science proclamaitions must routinely
avoid numbers so as to promote myths.

Stress from power on is irrelevant. But then electronics also
contain additional protection layers that makes that power cycling
irrelevant: inrush current limiter. More information unknown to those
who just *know* power cycling must be destructive. That is the problem
with junk science. It never first learns about basic technology - even
a 1950 technology called inrush current limiter - AND completely avoids
numbers. Once numbers are provided,, then it is obvious: turn it off
when done just like a TV or radio to perserve life expectancy and
eliminate wasteful power consumption.

Nonsense about "thermal cycling" is classic "snake oil".

Meanwhile, note what was posted about light bulbs. However, when one
first learns science or even consults ight bulb industry specs: power
cycling is not destructive to light bulbs. If power cycling was
destrutive, then orange traffic signals - power cycling all night long
- would be first to burn out; would often be seen failed. Those bulbs
fail so infrequently that sometimes the bulbs power cycled most -
orange - are not even replaced by LEDs. Reality - even using numbers
from the light bulb manufacturers - light bulb life expectancy is a
function of voltage and hours of operation. Power cycling is
irrelevant. There is no formula to relate power cycling to light bulb
life expectancy. But there are plenty of formulas from real world
scientists (not junk scientists) that relate life expectancy to voltage
and hours.

Just like 'thermal cycling', light bulb life expectancy is related to
power cycling only when junk science - including no science AND
especially no numbers - is promoted. Lurkers are warned about those
who always just know - and yet don't do the numbers.

Glenn Richards is invited to cite how electronics is manufactured at
upwards of 900 degrees for multiple times - and it not "thermal
stressed". Glenn Richards is invited to cite industry science (and I
will even help him by providing the light bulb industry bible found in
any good library: IES Lighting Handbook) to cite industry science that
demonstrates a relationship between power cycling (thermal cycling) and
life bulb life expectancy.

Glenn Richards wrote:
Mike Cawood, HND BIT wrote:
My late wife's stepfather, W Cutler of Wolverhampton, read in some
mentally deranged hifi magazine that you should always keep the
system switched on, ...

Yes... when hi-fi magazines talk about leaving the system switched on
permanently... I don't think that's *quite* what they meant!

Actually there's a lot to be said for leaving your kit on all the time
(if you're using it for more than say 8 hours in a day)... it eliminates
the "thermal cycling" effect. No, this is nothing to do with snake oil
or esoteric audiophile theories. If you heat metal up to 40-50 degrees
it expands, cool it back down to 18-20 degrees (normal room temperature)
it'll contract. Enough cycles and it'll fracture.

Also it avoids the surge current when you power it up. Think light bulbs
- they nearly always fail when you turn the power on. A sudden inrush
current into a cold filament causes a thermal shock. As an aside, the
bulbs for my wall lights in my living room are quite expensive, so I've
wired them through a 'soft switch' which fades them up to full
brightness when you turn them on and fades down to dark when you turn
them off. Practical advantage is that it avoids thermal shock to the
bulbs... and it looks *really* cool!

In article . com,
w_tom
wrote:

[snip]

Semiconductors are manufactured in repeated cycles from room
temperature to upwards of 900 degrees. Now that is real thermal cycling
- and it is not destructive. Do same items get thermal cycled when
temperature varies less than 100 degree?

Although I agree in general terms with your thesis, I would apply the above
with caution. The manufacturing process is quite different to the use.

Most domestic audio SS devices will be made of silicon-based
semiconductors. These will normally be designed to work with device
temperatures up to the order of 200 C - so quoting '900' (with no units)
would be misleading. The reality is that either the device, or its
electrical connections, or its bonding to the pack, may fail if you go too
much above the order of 200 C.

In practice, SS devices tend to be designed to be cycled many many times,
and, provided the designer chose and used them with care, there is a good
chance they will work for a very long time. Devices in circuit locations
where the power dissipation does not vary much tend to operate with low
device temperatures. Devices in, say, B or AB output stages will have their
temperatures vary far more with signal than between being powered up or
not.

I have two 30+ year old receivers. In daily use. No SS device failures so
far. I have two 25+ year old 200W power amps. One device failure last year
(intermittent) - which may have been the soldering onto the PCB, but I
suspect was the bonding inside the pack. The device in question was a class
A, voltage stage device, not an output device, used well within spec, so I
put this down to the normal laws of statistics for real-world devices...

So 1 transistor in about a hundred, in 25-30 years of daily use, often
being switched on/off more than once per day.

Hence if someone is worried by thermal cycling of the SS devices in their
audio amplifiers, then the best advice is that they should either never use
the units, or only play low-power 1kHz sinewaves into high impedance,
resistive, speakers. :-)

OTOH If you want to play music, then I regret to say that 'thermal cycling'
of the output devices generally goes with the territory.

Of course, you could go to class A output. But then the operating
temperatures are elevated almost all the time the unit is used. The
lifetime of devices is a strong function of device temperature, so the
chances are that the MTTF will be much lower for such 'thermal cycle
avoiding' designs than if you'd used a well designed B or AB unit. If you
used one that was on continuously, I have my doubts that it would run
without problems for 25-30 years - but might if designed with this in mind.
Would probably cost you far more overall, though.

In my experience, the bias levels in the decent amps I know of all settle
in a matter of a few seconds to minutes after they turn on. After that, it
is down to the music, the weather, and your central heating. :-)

So I'd agree. Just choose the music you want to hear, and enjoy it. :-)

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

w_tom wrote:

There is good reason to leave a system on so as to not excessivly
power cycle it. And then we apply numbers. Amazing how numbers
expose junk science reasoning. For example, power switch is
typically rated for 100,000 cycle: seven times every day of the year
for .... 39 years. IOW worry about something that is totally
irrelevant.

"junk science"... so how come when I just turned on my Audiotron there
was a loud bang and a smell of smoke? The power supply has blown... the
exact same thing happened to my other Audiotron a few months back (a
replacement PSU fixed it).

The unit has been running fine for months, it was only turned off while
I moved it to a new location.

"w_tom" (why can't you people use your real names?) is invited to learn
about posting etiquette and understand why you shouldn't top-post
(except perhaps in a Microsoft group), and why you should trim quotes.

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

IT consultancy, hardware and software support, broadband installation

In article , Glenn Richards
wrote:
w_tom wrote:

There is good reason to leave a system on so as to not excessivly
power cycle it. And then we apply numbers. Amazing how numbers
expose junk science reasoning. For example, power switch is typically
rated for 100,000 cycle: seven times every day of the year for ....
39 years. IOW worry about something that is totally irrelevant.

"junk science"... so how come when I just turned on my Audiotron there
was a loud bang and a smell of smoke? The power supply has blown... the
exact same thing happened to my other Audiotron a few months back (a
replacement PSU fixed it).

I suspect the answer may be "junk engineering" :-) ...although that is a
harsh phrase, and I'd need to know more to be sure. However, the designer
should know what surge currents, etc, arise when the unit is switched on,
and choose components and a design that reliably deals with this.

The unit has been running fine for months, it was only turned off while
I moved it to a new location.

Given what you say, I can understand why you are wary. However my
inclination would be either to get the design modified, or change to
something that was better designed and made. Not to assume behaviour like
this was either acceptable or a 'norm' for well designed and made
equipment.

Since you often report your anecdotes, I will recount one of my own...

Many years ago, when I joined 'Armstrong' they had two general tasks for
me. One was to develop an entirely new amplifier, etc. The other was to
re-examine their existing range to see if it could be 'improved'.

I noticed that the existing 600 range amplifier units had a 'thermal delay'
in the PSU. This was a series resistor shunted with a switch. The switch
was a bimetallic strip, with a heater element. The arrangement meant that
when the unit was turned on from 'cold' the initial inrush had to go
through the resistor. However after about 10-20 seconds the heater operated
the bimetallic switch, and the resistor was bypassed.

I was told this switch was unreliable, but seemed to be essential otherwise
the sets might fail. Yet it was clear that many other manufacturers didn't
employ anything like it in their PSUs and did not seem to have a problem.

It cost a fair bit. It also tended to alarm some purchasers since the first
few times a new amplifier was switched on the heating element tended to
issue a smell like burning, and even sometimes a whisp of smoke!

Investigating, I found that the switch was present only because the diodes
chosen for the PSU rectifier had far too low a surge current rating. So I
changed to a much higher surge rating for the diodes and removed the
switch. The extra cost of the diodes was trivial compared with the saving
from not needing a switch.

The calls from new owners worried about the 'burning' vanished. The number
of sets returned for PSU problems also vanished.

All this required was to ensure that those components affected by the
switch on process were chosen to meet the requirements.

The root of the above problem was partly that the orginal designer did not
really fully understand the properties of solid state devices, so didn't
fully take the relevant factors into account. He was very skilled and
experienced with valves - where the time taken to warm the rectified valve
leads to different behaviour. But the failure or stress modes of solid
state devices were outwith his experience. His valve designs gave no
equivalent problems, because he understood how to design them so that they
didn't.

The experience was useful for me. It meant that when I designed a new (700)
amp I could ensure that although the switch-on surge was of the order of
100A, the design was reliable. I've been using two 600s and two 700s for
the last 20-30 years. No failures in their PSUs or related to switchon.
Indeed, FWIW, one of my main personal concerns at the time was that units
would be reliable in use. This benefits both the customers and the company
in my view.

None of the above is 'rocket science'. It just requires the designer to be
aware of what they are doing, device specs, and a maker who will then use
the required components - not try to cheese-pare by using something
'cheaper' which may cost more in the long run!

Thus if your 'Audiotron' unit has a specific failure mode at switch-on I'd
be inclined to view its design with some caution. If the circuit diagrams,
etc, are available, let us know. We may be able to spot a 'fix'. However I
can't say anything more specific as I am afraid I don't know anything about
it.

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

When computer was turned off, then it did not restart. Clearly this
demonstrates power cycling causes failure. Yes, if using junk science
reasoning based only upon observation. Instead use logical facts to
create a conclusion. First learn the reasons why. In normal
operation, a pullup resistor failed. With a failed pullup, then boot
circuit for a voltage regulator did not restart a power supply. Power
cycling did not cause this failure. Resistor was damaged in normal
operation. But those who just know, instead, did classic junk science
reasoning. Because a power supply did not restart during a power
cycle, then clearly failure must have been created by power cycling.
Reality - discover first why something failed - demonstrates that
normal operation created the damage. Learn reasons why before drawing
a conclusion is a concept taugh in science class. Junk scientists
don't first learn technical facts. They know only upon observation.

Same junk science also proves that life could be created by
spontaneous regeneration. Another example of observation sufficient to
prove a fact: science be damned.

Power cycling is has been declared destructive because component
analysis was not performed. What part failed, when and why? Without
that answer, then declarations about destructive power cycling are only
classic junk science proclamations.

Normal operation caused pullup failure. But junk science declared
the failure due to power cycling because a human used only observation
as proof; technical facts be damned.

Glenn Richards wrote:
"junk science"... so how come when I just turned on my Audiotron there
was a loud bang and a smell of smoke? The power supply has blown... the
exact same thing happened to my other Audiotron a few months back (a
replacement PSU fixed it).

The unit has been running fine for months, it was only turned off while
I moved it to a new location.