In article ,
Phil Allison wrote:
But I'll bet your wrong. With the 33/303 or 33/405. the preamp was
earthed via the mains lead.

** Not the case with units exported to Australia.

I suppose I'll have to take your word for it. But have you one there to
check - rather than relying on your memory which seems pretty flaky given
you didn't remember just how the 405 speaker ground was wired.

33s and FM3s were supplied with a 2 wire lead with a US style 2 pin plug
- so most owners changed the US style plug on the 33 to an Aussie 3
pin one. FM3s simply plugged into one of the 33's two pin switched
outlets.

The 33 I have here has a three pin Bulgin mains input, where the earth
pin is connected to chassis. On a totally Quad installation you used a
three core mains lead to it, and it provided the mains ground to
everything else. The mains to the 303 (or early 405) would be a two core
fed from the US mains outlet on the back of the 33 - as would the FM
tuner.

303 and 405 Power amps were safety earthed via their 3 wire AC leads.

I really don't believe that Quad altered things to that extent for other
countries. The 303 had the same mains input connector as used on the 33,
to allow it to have a mains ground via that if needed when used on a non
Quad setup.

Most of the 303s I worked on were from recording studios and the Bulgin
plug and sockets had been changed to XLR-LNE mains connectors.

Any half decent facility would also use balanced inputs. One of the
benefits of which is the absence of the ground loop problems you can get
with unbalanced. Are you sure you're not talking about the Quad 50 - which
used the same case as the 303, but was a mono amp with LNE mains connector?
They were common in pro facilities at one time. The 303, not.

FYI:

It has long been illegal to supply a non standard IEC mains lead in
Australia - they are classed as "prescribed items" and must carry
agency approval.

Again, I'm not really interested in the quirks of OZ regs. They have
plenty of oddball ideas about many things.

But the bit you seem totally to be missing is that Quad changed the mains
grounding ideas too over the life of the 405. Which I was hoping a real
expert could explain fully to me.


** All 405s have a 3 pin IEC mains inlet, so are safety grounded.

I have never come across anyone so ****ing stupid as to interfere with
this here in Australia.

Not surprising if they're all as thick as you.

** Huh ???

Try learning to READ you ****ING MORON !!

Are you trying to tell me regs in OZ haven't changed since the mid 70s
when the 405 arrived?

They have in the UK. And providing a safety ground via a DIN cable doesn't
conform. It must be capable of taking out a 13 amp plug fuse within a set
time period in event of a fault. Which is why all appliance mains leads in
the UK are now of a greater cross section than once was allowed. The US
style flat two pin mains outlets on the 33 are also no longer allowed. Oh
- and neither is the XLR mains LNE. It cannot be used domestically.

Now accepting these things were changed for a good reason - and adopted by
Quad themselves - do you still say what Quad did in the original version
'must not be interfered with'? If so, keep your head firmly in the sand...

--
*Why is it that most nudists are people you don't want to see naked?*

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

In article ,
Phil Allison wrote:
A very nasty example of scenario "2" occurs when the equipment plug has
earth and neutral wires reversed - which goes unnoticed until the day it is
plugged into an outlet that has active and neutral reversed.


Crikey. Have you never heard of RCDs in OZ? I sort of guessed it was third
world - but not that bad.

--
*Aim Low, Reach Your Goals, Avoid Disappointment *

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

In article om,
mick wrote:
IIRC the shield on a DIN connector was always intended to be the chassis
connection, with pin 2 optionally being an isolated signal ground. Quad
were rather naughty when they connected pin 2 to chassis in the 303.
Keeping it separate would have allowed more flexible connection without
introducing hum loops. Linking the shield to pin 2 is fine for low level
inputs, but it shouldn't be done when linking to other equipment.

The 33 also supplied +12v DC on pin 4 for 'professional use'.

Modern electrical safety earthing might allow the 303 to be powered from
the 33 as the mains transformer appears to include an earthed shield
which would isolate the secondary from the primary. That would make it a
Class II (double-insulated) appliance. Of course, the shield would have
to be capable of carrying any fault current from the mains until the
fuse blows. Also, all mains leads (& probably internal mains wiring)
would need an outer sheath to provide double insulation.

It's likely pretty involved to provide a Class 2 device with a metal case.
The 405 miles away - the transformer mains connections are totally exposed
when the top cover is removed. The BBC installed a plastic cover over that
on their ones.

What intrigued me was the DC on the output of the later amp when not
connected to anything other than mains. Some 20 odd mV. Which goes to
about 2 mV when the phono ground is connected to chassis. The early amp
where the input ground is connected to chassis always at the 2 mV.

--
*Is there another word for synonym?

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

In article , Brian Gaff
wrote:
I have a Rogers Cadet here, and the mains through connectors are lethal.
I don't know how they got away with them at the time. Brian

Back then there was a tendency to assume people buying serious hifi kit
would have a clue about such matters. Particularly when many units could be
bought without any case, thus exposing high voltages (in safety terms). The
makers assumed the buyer was an adult who would take responsibility to
deploying and using safely.

It was also common for either the pre or power amp to be mains powered
from the other via an 'umbilical' of some kind. Also why then it was common
to include circuit diagrams, etc.

Different world.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Here's a pic of the 33 rear from the handbook. Even Phil should be able to
see the three pin mains input connector.


http://i139.photobucket.com/albums/q...psb60c597a.jpg

--
*I started out with nothing... and I still have most of it.

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

On Sat, 02 Aug 2014 11:24:57 +1000, Phil Allison wrote:

"mick"

That would make it a Class II (double-insulated) appliance.

** Absurd crap !!!



Ah... yes... That screen couldn't make it Class II could it? It would
need to be earthed. lol I missed that one!

I take that back, the Quad 303 definitely requires a mains earth to the
metalwork in order to comply with current UK regs. It can't rely on the
input connector as that can be unplugged while leaving the mains supply
connected. That makes it even more sensible not to connect signal earth
directly to chassis in the 303.


The basic principle of Class II is *NOT* to rely on the mains earth for
user safety.

Two reasons:

1. If the mains earth connection is missing anywhere, the equipment
still operates ( with no warning to the user) and you have no safety.

2. If the AC outlet or equipment plug is miswired, active can appear on
the earth conductor and you have a lethal situation.



The principle of Class II is that there is NO REQUIREMENT to rely on
earthing for user protection at all, as all mains-carrying wiring is
double-insulated away from the user side. Note that phone chargers etc
are virtually all Class II. In the UK these have a dummy plastic earth
pin which is only used to open the live & neutral shutters on the socket.

The mains output sockets on the 33 almost certainly wouldn't be legal now
anyway. Getting live and neutral right way round is a 50/50 guess.


A very nasty example of scenario "2" occurs when the equipment plug has
earth and neutral wires reversed - which goes unnoticed until the day it
is plugged into an outlet that has active and neutral reversed.


Agreed. It's only relatively recently that domestic wiring in the UK has
been using earth-leakage protection. Older installations (including my
own!) don't have it - in fact, I'm still on rewirable fuses here!
Consequently we tend to be careful about wiring plugs & sockets up
correctly. Even when properties are being refurbished over here, there
is no legal requirement to change any existing distribution boards etc.
unless they are damaged. Consequently there are a lot of houses in the
same condition as mine.

"Dave Plowman (Nutcase ****head )


Crikey. Have you never heard of RCDs in OZ?


** We have plenty of Ratbag Criminal Dickheads here.

All of them ****ing, pommie ****s like you.

"Dave Plowman (Criminal Lunatic)


** Not the case with units exported to Australia.

I suppose I'll have to take your word for it.

** Go and get ****ed.


33s and FM3s were supplied with a 2 wire lead with a US style 2 pin plug
- so most owners changed the US style plug on the 33 to an Aussie 3
pin one. FM3s simply plugged into one of the 33's two pin switched
outlets.

The 33 I have here has a three pin Bulgin mains input, where the earth
pin is connected to chassis. On a totally Quad installation you used a
three core mains lead to it, and it provided the mains ground to
everything else. The mains to the 303 (or early 405) would be a two core
fed from the US mains outlet on the back of the 33 - as would the FM
tuner.

** Totally unsafe and illegal in Australia and most places.


303 and 405 Power amps were safety earthed via their 3 wire AC leads.

I really don't believe that Quad altered things to that extent for other
countries.

** Quad altered nothing.

The responsibility to comply with safety regs was with the local importers.

Originally " British Merchandising" and then "Audio Engineers".


Most of the 303s I worked on were from recording studios and the Bulgin
plug and sockets had been changed to XLR-LNE mains connectors.

Any half decent facility would also use balanced inputs.

** So what - FOAD you stinking TROLL.


FYI:

It has long been illegal to supply a non standard IEC mains lead in
Australia - they are classed as "prescribed items" and must carry
agency approval.

Again, I'm not really interested in the quirks of OZ regs.


** Nothing quirky - just far more sane than the ****ing absurd pommy ones.



** All 405s have a 3 pin IEC mains inlet, so are safety grounded.

I have never come across anyone so ****ing stupid as to interfere
with
this here in Australia.

Not surprising if they're all as thick as you.

** Huh ???

Try learning to READ you ****ING MORON !!

Are you trying to tell me regs in OZ haven't changed since the mid 70s
when the 405 arrived?

** Try learning to READ you ****ING MORON !!


They have in the UK. And providing a safety ground via a DIN cable doesn't
conform.

** Try learning to READ you ****ING MORON !!


Now accepting these things were changed for a good reason - and adopted by
Quad themselves - do you still say what Quad did in the original version
'must not be interfered with'?

** Try learning to READ you ****ING MORONIC **** !!

Quad fitted an **IEC** 3 pin inlet to every 405 with safety ground
included.

All Australians did was ****ING USE IT as required by law.

God I how I hope you ancient, ****ed up 405s KILL YOU !!!!!!!!!



..... Phil

In article om, mick
wrote:
On Sat, 02 Aug 2014 11:24:57 +1000, Phil Allison wrote:

"mick"

That would make it a Class II (double-insulated) appliance.

** Absurd crap !!!



Ah... yes... That screen couldn't make it Class II could it? It would
need to be earthed. lol I missed that one!

I've assumed that double insulation means two different layers of
insulation (even if one is 'air' in some situations). Which in itsef is a
different issue to anything being connected to earth. However I've not
known the actual regs for many years now!


It's only relatively recently that domestic wiring in the UK has
been using earth-leakage protection. Older installations (including my
own!) don't have it - in fact, I'm still on rewirable fuses here!

Here also. The only RCDs I have are ones I plug in to use garden equipment
though.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 01/08/2014 14:37, Phil Allison wrote:

Rubbish.

Oh! They've let you out again have they?* How long is it for this time?


* or did you simply chew the leg irons off?

--
David Kennedy

http://www.anindianinexile.com