In article , Jim Lesurf wrote:
Just before Christmas a colleague brought me the electronics from his TT as
it had stopped working. (Well regarded UK brand.)

Examining it, and working out the circuit, worried me.

There was no mains transformer, and no mains switch. The circuit was
therefore live all the time the deck was plugged into the mains, regardless
of the switches and indicators visible/useable on the deck.

There's a lot of dodgy design nowadays, the commonest manifestation being the
"lumpy mains plug" type of power supply with no switch, connected to the
equipment via one of those horrible little co-axial connectors with no
standardisation of physical size, voltage or polarity - if it even has a
polarity, because some of them are AC and some of them are DC. The only power
switch is in the low-voltage circuit, and being fitted to the equipment itself
probably gives the unsuspecting owner the comfortable feeling that when it's
switched off it's switched off.

Separate power supplies are so common nowadays, and almost unheard of when I
was young, that I wonder what can have changed? In reality, two boxes are more
expensive than one, considerably more ungainly, and with the huge variety of
power requirements a splendid opportunity for error, so there seems no
practical sense in not building the power supply into the equipment. My best
guess is that perhaps it is the result of some committee's misguided notion of
a safety feature, but does anybody know why?

Rod.

In article ,
Trevor Wilson wrote:
**It is "plain suitable wire" (i.e.: figure 8) which may alter the
frequency response in some systems.

Not in any I've tried. Just how long are the runs, what is the cross
sectional area of the conductor, and the impedance range of the speaker?

--
*Being healthy is merely the slowest possible rate at which one can die.

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

In article ,
Roderick Stewart wrote:
There's a lot of dodgy design nowadays, the commonest manifestation
being the "lumpy mains plug" type of power supply with no switch,
connected to the equipment via one of those horrible little co-axial
connectors with no standardisation of physical size, voltage or
polarity - if it even has a polarity, because some of them are AC and
some of them are DC. The only power switch is in the low-voltage
circuit, and being fitted to the equipment itself probably gives the
unsuspecting owner the comfortable feeling that when it's switched off
it's switched off.

If someone thinks a wall wart fed device is totally isolated from the
mains when switched off locally, let Darwin's law apply. However, perhaps
the majority of devices these days need permanent power to maintain
settings or to allow the use of a remote, etc. So really no different from
a VCR which has always remained powered up to keep the clock running.

IIRC, all CE marked wall warts have thermal fuses so shouldn't present a
fire risk. Nor is it a recent thing having permanently powered
transformers. Door bells have used then for decades. Bathroom shaver
sockets too.

--
*The closest I ever got to a 4.0 in school was my blood alcohol content*

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

"Roderick Stewart" wrote in message
om...
In article , Jim Lesurf wrote:
Just before Christmas a colleague brought me the electronics from his TT
as
it had stopped working. (Well regarded UK brand.)

Examining it, and working out the circuit, worried me.

There was no mains transformer, and no mains switch. The circuit was
therefore live all the time the deck was plugged into the mains,
regardless
of the switches and indicators visible/useable on the deck.

There's a lot of dodgy design nowadays, the commonest manifestation being
the
"lumpy mains plug" type of power supply with no switch, connected to the
equipment via one of those horrible little co-axial connectors with no
standardisation of physical size, voltage or polarity - if it even has a
polarity, because some of them are AC and some of them are DC. The only
power
switch is in the low-voltage circuit, and being fitted to the equipment
itself
probably gives the unsuspecting owner the comfortable feeling that when
it's
switched off it's switched off.

Separate power supplies are so common nowadays, and almost unheard of when
I
was young, that I wonder what can have changed? In reality, two boxes are
more
expensive than one, considerably more ungainly, and with the huge variety
of
power requirements a splendid opportunity for error, so there seems no
practical sense in not building the power supply into the equipment. My
best
guess is that perhaps it is the result of some committee's misguided
notion of
a safety feature, but does anybody know why?


Yes, there's wacky legislation afoot that any device with a captive power
lead must be capable of being suspended by that lead, hence the advent of
kettle leads.

In any case, separate 'wall-warts' must cost next to nothing these days, now
that their production has been going on so long...

Now, to drag this thread back on topic - did you know that they have
recently discovered secret records in the Bundesarkiv that prove beyond
doubt that Adolf Hitler could reliably differentiate between speaker cables
on early German audio kit....?



















That should do it.....

In article , Dave Plowman (News) wrote:
If someone thinks a wall wart fed device is totally isolated from the
mains when switched off locally, let Darwin's law apply. However, perhaps
the majority of devices these days need permanent power to maintain
settings or to allow the use of a remote, etc. So really no different from
a VCR which has always remained powered up to keep the clock running.

The difference is that the standby power consumed by a piece of electronic
equipment is actually doing something (either running a clock or maintaining
the equipment in a state of instant readiness), whereas any waste power
consumed by an outboard power supply that is only "switched off" in its low
voltage output circuit is doing nothing whatsoever. It's simply wasting power
because the switch has been designed into the wrong place.

Most people would be completely unaware of the difference, and would simply
assume that the equipment will work correctly and safely as provided by the
manufacturer, not an unreasonable assumption in today's world of rules
regulations and trading standards. Yes, it would be to their advantage to
learn about electronics and understand more about how their domestic
equipment works, but that's not reality, and it's unlikely to change.

Rod.

In article , Keith G wrote:
Now, to drag this thread back on topic - did you know that they have
recently discovered secret records in the Bundesarkiv that prove beyond
doubt that Adolf Hitler could reliably differentiate between speaker cables
on early German audio kit....?

Not much help to him if he couldn't differentiate between a winning strategy
and a losing one.

On the other hand, the acoustic isolation of that undergound bunker must have
been superb, so he'd have enjoyed really good audio quality while he could.

Rod.

On Wed, 11 Jan 2006 21:20:31 GMT, "Trevor Wilson"
wrote:


"mick" wrote in message
news
But you can't hear the effect of cable inductance or capacitance over a
reasonable length of any standard cable.

**Without specifying the impedance of the load, the length of the cable and
the inductance of the cable, there is NO WAY you can make such a
pronouncement. BTW: I NEVER mentioned (speaker) cable capacitance. It is not
relevant.

The value is simply too small to
have an effect at audio frequencies.

**Oh really? When did you last study electrical theory?

I contunue to do so, and he's right in all but the most extreme
systems.

You *can* hear the difference in
levels at the speaker terminals though, if the feed is switched between
monster cable and bell wire or computer ribbon cable.

**Given sufficient differences in resistivity, yes. BTW: Unless the computer
ribbon cable is specifically configured for low inductance, there won't be
much difference in inductance, between all the above cables.

But of course there's no point in using ribbon cable *unless* you so
configure it - which takes about ten minutes.

That's why the
levels need to be matched, and at 2 frequencies to get rid of cables with
daft things like discrete capacitors and inductors built into them to
change their response artificially.

**See if you can understand:

Figure 8 cable has the highest inductance of any easily available cable.

No, it doesn't. Parallel spaced conductors do, such as standard '300
ohm' antenna feeder (the 300 ohm bit is a dead giveaway if you know
your electrical theory), and of course Naim speaker cable.

Cables like Kimber, Goertz and others have LOW inductance figures. They are
LESS likely to affect the frequency response than figure 8 (zip) cables.

Agreed, but the difference is negligible in most case, and arguably
inaudible in any but the most pathological cases (such as fifty feet
into a 'stat speaker).

Conductors are conductors, only the
loop resistance can make a difference and that can be calibrated out of
the test.

**Wrong. Go hit the books and study up on electrical theory. After you do,
we can discuss.

No, you just keep bleating on about minor *measured* differences,
without ever addressing practical listening tests.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Wed, 11 Jan 2006 13:48:49 +0200, Forwarder wrote:

Don Pearce wrote:

On Wed, 11 Jan 2006 13:18:19 +0200, Forwarder wrote:


Joe Folly wrote:


To stop people from trying the test with a "cheat cable" just to win
the money.


Thanks Joe for answering my question.

Can you give a guess on this one also:

"Just how would that be done in practice? (frequency response AT THE
SPEAKER TERMINALS must be within 0.1dB.) Some box in between? Volume
level adjustment? How?"


If the cables are both reasonable for the job, then the response will
be within 0.1dB - there is nothing that needs to be done. See my later
thread on a protocol.


So in effect, stewart is suggesting that some exotic speaker cable must
sound the same as lamp cord (have the same freq resp) and sound
different at the same time? Wierd.

No, they actually do measure just the same in almost all cases -
despite the bull**** claims on some 'exotic' cable websites. For those
that might not, such as long lengths of ultra-low inductance cable, I
can substitute a low-inductance cable made from cheap computer ribbon
cable.

We recently ahd a row with this stewart on the same subject. I had
*accepted* his challenge. But when he started squir.. err.. stipulating
this and some other conditions (same gauge, same length, etc) I backed
out. Being the slimy low-life audiophool that I am.

And now you find that adopting an anonymous 'handle' improves your
credibility? BTW, you are flat lying about any stipulations regarding
length and gauge - the *only* conditions have *always* been the level
matching previously noted.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Wed, 11 Jan 2006 13:18:19 +0200, Forwarder wrote:

Joe Folly wrote:

To stop people from trying the test with a "cheat cable" just to win
the money.


Thanks Joe for answering my question.

Can you give a guess on this one also:

"Just how would that be done in practice? (frequency response AT THE
SPEAKER TERMINALS must be within 0.1dB.) Some box in between? Volume
level adjustment? How?"

In practice, it just happens with cables. In a pathological case such
as noted above, it would be very easy for me to rig up an equivalent
cable to any exotic, using cheap 'off the shelf' materials such as
computer ribbon cable - and maybe a quid's worth of inductors and
capacitors if some clown is trying a really outrageous cheat.

The level-matching requirement was really intended for amplifiers, as
this was the basis of the original international challenge which was
set up on rec.audio.high-end about seven years ago. No takers for that
one, either, even with a $5,000 pool.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Wed, 11 Jan 2006 14:40:59 +0200, Forwarder wrote:

Don Pearce wrote:

On Wed, 11 Jan 2006 13:48:49 +0200, Forwarder wrote:


Don Pearce wrote:


On Wed, 11 Jan 2006 13:18:19 +0200, Forwarder wrote:



Joe Folly wrote:



To stop people from trying the test with a "cheat cable" just to win
the money.


Thanks Joe for answering my question.

Can you give a guess on this one also:

"Just how would that be done in practice? (frequency response AT THE
SPEAKER TERMINALS must be within 0.1dB.) Some box in between? Volume
level adjustment? How?"


If the cables are both reasonable for the job, then the response will
be within 0.1dB - there is nothing that needs to be done. See my later
thread on a protocol.


So in effect, stewart is suggesting that some exotic speaker cable must
sound the same as lamp cord (have the same freq resp) and sound
different at the same time? Wierd.


Don't understand

Is it not freq response that determines how a cable might "sound" if at
all? What's not to understand?



We recently ahd a row with this stewart on the same subject. I had
*accepted* his challenge. But when he started squir.. err.. stipulating
this and some other conditions (same gauge, same length, etc) I backed
out. Being the slimy low-life audiophool that I am.


Nothing wrong with that. It would be too easy to insist that you
compare three feet of 14 gauge with a hundred yards of bell wire.


Agreed, that would be ludicrous..

Such
stipulations are absolutely vital.

To a point.. My speaker cables are very special construction, braided,
teflon shielding, etc. One would have to take them apart to determine
the "gauge" for instance..

Not interested, so long as I can achieve a level match in your
preferred system, using only cheap wire.

The comparison is between types of
cable, not between pieces of cable.

Care to open this one up a bit? Thanks.

See above for the 14AWG/bellwire argument, with which you already
agreed. We're looking only for a very rough match of gross LR
parameters, and I'd be using a roughly equivalent loop resistance of
plain copper wire with PVC insulation. Your 'exotic' construction and
materials will prove to have *zero* audible benefit - and of course
*I* am the one who's putting my money where that opinion is.

--

Stewart Pinkerton | Music is Art - Audio is Engineering