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Running an amplifier unearthed



 
 
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  #1 (permalink)  
Old November 29th 17, 07:55 AM posted to uk.rec.audio
D.M. Procida
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Posts: 140
Default Running an amplifier unearthed

If you read uk.d-i-y, you may have seen a thread ("This appliance must
be earthed") about Dutch mains sockets, which are often unearthed.

If I plug a Cyrus 1 amplifier (which has an extremely metal case and a
stern label saying "This appliance must be earthed") into an unearthed
socket, do I risk death by electrocution, or worse, poorer sound
quality?

Daniele
  #2 (permalink)  
Old November 29th 17, 08:26 AM posted to uk.rec.audio
Brian Gaff
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Posts: 637
Default Running an amplifier unearthed

Well, it depends on what else you have connected to it I suppose. You would
need to find out in this case why it says it has to be earthed, If its just
hum and buzz and pick up of rubbish then its safe but if it has large
capacitors between the earth and live etc, then you will get quite a belt.
I guess that if they are specifying an earth they probably have a reason
for running it that way, but I doubt if its going to be in danger of the
mains shorting to the earth, that would be silly. Its mainly appliances
which may be in the vicinity of water or which have components that might
fail like powerful motors that need an earth. Fridges Washing machines,
Vacuums etc.
I never did quite get why garden equipment has no earth though.
Brian

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"D.M. Procida" wrote in
message
...
If you read uk.d-i-y, you may have seen a thread ("This appliance must
be earthed") about Dutch mains sockets, which are often unearthed.

If I plug a Cyrus 1 amplifier (which has an extremely metal case and a
stern label saying "This appliance must be earthed") into an unearthed
socket, do I risk death by electrocution, or worse, poorer sound
quality?

Daniele



  #3 (permalink)  
Old November 29th 17, 08:42 AM posted to uk.rec.audio
Woody[_4_]
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Posts: 145
Default Running an amplifier unearthed


"D.M. Procida" wrote in
message
...
If you read uk.d-i-y, you may have seen a thread ("This appliance
must
be earthed") about Dutch mains sockets, which are often unearthed.

If I plug a Cyrus 1 amplifier (which has an extremely metal case and
a
stern label saying "This appliance must be earthed") into an
unearthed
socket, do I risk death by electrocution, or worse, poorer sound
quality?



In fact you will find that most amplifiers with a fixed cable use two
core and no earth, as do almost all other separates.

In practice if there is to be an earth within a hi-fi system there
should only ever be one and very often that used to be on the
turntable. If there is more than one you will likely end up with a
'hum loop' around the multiple earths causing a very low level but
continuous hum form the speakers.

If you have an amp with a 'kettle' plug connection if you have or know
someone who has a multimeter you should check for continuity between
the earth pin (the longer pin in the fixed plug) and the chassis
and/or the screen (outer) of any phono connector. If there is
continuity then use of an earthed cable is a good idea but you won't
damage the equipment and are unlikely to damage yourself if you don't.


--
Woody

harrogate3 at ntlworld dot com


  #5 (permalink)  
Old November 29th 17, 10:50 AM posted to uk.rec.audio
Phil Allison[_3_]
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Posts: 312
Default Running an amplifier unearthed

Woody wrote:

---------------


In fact you will find that most amplifiers with a fixed cable use two
core and no earth, as do almost all other separates.


** But ONLY if they are built to Class 2 standard as indicated by the famous double square symbol on the back.

All the rest with 3 core cable and standard 3 pin IEC inlets require a safety ground.


In practice if there is to be an earth within a hi-fi system there
should only ever be one and very often that used to be on the
turntable.



** Never the TT, that is plain insane.

A power amp or integrated amp is the wise choice and the TT ground lead connected to the pre-amp or integrated amps chassis.

An all class 2 system that includes a TT invariably hums - till you add a safety earth somewhere.


..... Phil


  #6 (permalink)  
Old November 29th 17, 10:57 AM posted to uk.rec.audio
Phil Allison[_3_]
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Posts: 312
Default Running an amplifier unearthed

D.M. Procida wrote:

----------------------

If you read uk.d-i-y, you may have seen a thread ("This appliance must
be earthed") about Dutch mains sockets, which are often unearthed.

If I plug a Cyrus 1 amplifier (which has an extremely metal case and a
stern label saying "This appliance must be earthed") into an unearthed
socket, do I risk death by electrocution, or worse, poorer sound
quality?


** The former, poor sound is also an alternative.

FFS a "safety ground" is there for the bloody obvious reason that it prevents exposed metalwork becoming live in case of a fault inside the equipment OR some connected piece of gear has a live chassis due to an internal fault OR wrong mains plug wiring.



..... Phil




..... Phil
  #7 (permalink)  
Old November 29th 17, 12:09 PM posted to uk.rec.audio
Dave Plowman (News)
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Posts: 5,872
Default Running an amplifier unearthed

In article
,
D.M. Procida wrote:
If you read uk.d-i-y, you may have seen a thread ("This appliance must
be earthed") about Dutch mains sockets, which are often unearthed.


If I plug a Cyrus 1 amplifier (which has an extremely metal case and a
stern label saying "This appliance must be earthed") into an unearthed
socket, do I risk death by electrocution, or worse, poorer sound
quality?


The warning simply means the construction doesn't conform to the EU
requirements of a device with metal parts and no earth. Assuming it is in
good condition, I doubt you'd get electrocuted by it with no earth.

Noise figures as part of an installation may be poorer, though.

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

Dave Plowman London SW
To e-mail, change noise into sound.
  #8 (permalink)  
Old November 29th 17, 12:12 PM posted to uk.rec.audio
Dave Plowman (News)
external usenet poster
 
Posts: 5,872
Default Running an amplifier unearthed

In article ,
Woody wrote:
In practice if there is to be an earth within a hi-fi system there
should only ever be one and very often that used to be on the
turntable. If there is more than one you will likely end up with a
'hum loop' around the multiple earths causing a very low level but
continuous hum form the speakers.


I've never ever seen a system where the mains earth is provided via the
turntable. Most usually by the device where the mains is switched from
like the amp or pre-amp, if that supplies switched mains for other things.

Signal ground is a different matter.

--
*A conclusion is the place where you got tired of thinking *

Dave Plowman London SW
To e-mail, change noise into sound.
  #9 (permalink)  
Old November 29th 17, 12:31 PM posted to uk.rec.audio
Woody[_4_]
external usenet poster
 
Posts: 145
Default Running an amplifier unearthed


"Dave Plowman (News)" wrote in message
...
In article ,
Woody wrote:
In practice if there is to be an earth within a hi-fi system there
should only ever be one and very often that used to be on the
turntable. If there is more than one you will likely end up with a
'hum loop' around the multiple earths causing a very low level but
continuous hum form the speakers.


I've never ever seen a system where the mains earth is provided via
the
turntable. Most usually by the device where the mains is switched
from
like the amp or pre-amp, if that supplies switched mains for other
things.

Signal ground is a different matter.



Although it is getting on a bit my Hitachi DD turntable has three-core
mains and the chassis and pickup are connected to it - don't ask me
why as I don't know. However I have never had any audible hum on the
system, and my amp and all the other separates are two-core mains.


--
Woody

harrogate3 at ntlworld dot com


 




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