My amplifier has two outputs. One is switched, and used for the
speakers in the living room. The other is taken via a separate
switch box to speakers in the dining room and kitchen.

Originally, the relative sound levels in all three rooms were
reasonably matched. However, during a kitchen refit, I had to
get rid of the conventional speakers, and fitted a pair of small
KEF in-ceiling units. These have a rather lower output level. If
I deselect the dining room pair, the kitchen is well enough
matched to the living room.

As a least cost work-around, it strikes me that I might be able
to improve the situation by inserting series resistors in the
feed to the dining room. Would this work? Living in a semi, I
don't run at particularly high sound levels.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

"Chris J Dixon" wrote in message
...
My amplifier has two outputs. One is switched, and used for the
speakers in the living room. The other is taken via a separate
switch box to speakers in the dining room and kitchen.

Originally, the relative sound levels in all three rooms were
reasonably matched. However, during a kitchen refit, I had to
get rid of the conventional speakers, and fitted a pair of small
KEF in-ceiling units. These have a rather lower output level. If
I deselect the dining room pair, the kitchen is well enough
matched to the living room.

As a least cost work-around, it strikes me that I might be able
to improve the situation by inserting series resistors in the
feed to the dining room. Would this work? Living in a semi, I
don't run at particularly high sound levels.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

If the dining room application is for background music during meals, then it
should work fine by attenuating the 'speakers relative to the others. Unless
you know how many dBs you need to attenuate, and can then calculate the
series resistance value, you'll be better off getting a loudspeaker volume
control as is used in Pubs and Restaurants for just such an application.
They're not expensive and it does allow you to make changes easily.

This will do it.
http://cpc.farnell.com/_/bt936/louds...all/dp/AV01580

It's a transformer-based design (presumably a variable auto-transformer,
like a Variac). A bit more expensive than a couple of 5-10 watt resistors,
but the extra flexibility is worth-while.

S.

--
http://audiopages.googlepages.com

"Serge Auckland" wrote in message
...

"Chris J Dixon" wrote in message
...
My amplifier has two outputs. One is switched, and used for the
speakers in the living room. The other is taken via a separate
switch box to speakers in the dining room and kitchen.

Originally, the relative sound levels in all three rooms were
reasonably matched. However, during a kitchen refit, I had to
get rid of the conventional speakers, and fitted a pair of small
KEF in-ceiling units. These have a rather lower output level. If
I deselect the dining room pair, the kitchen is well enough
matched to the living room.

As a least cost work-around, it strikes me that I might be able
to improve the situation by inserting series resistors in the
feed to the dining room. Would this work? Living in a semi, I
don't run at particularly high sound levels.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

If the dining room application is for background music during meals, then
it should work fine by attenuating the 'speakers relative to the others.
Unless you know how many dBs you need to attenuate, and can then calculate
the series resistance value, you'll be better off getting a loudspeaker
volume control as is used in Pubs and Restaurants for just such an
application. They're not expensive and it does allow you to make changes
easily.

This will do it.
http://cpc.farnell.com/_/bt936/louds...all/dp/AV01580

It's a transformer-based design (presumably a variable auto-transformer,
like a Variac). A bit more expensive than a couple of 5-10 watt resistors,
but the extra flexibility is worth-while.

S.

--
http://audiopages.googlepages.com

There is something odd about that part - a pair of audio transformers rated
60W with 20Hz to 20kHz response in package 140mm x 85mm x 45mm - and
variable as well - and for £20. Don't expect it to sound very good.

Michael Kellett

"MK" wrote in message
...

"Serge Auckland" wrote in message
...

"Chris J Dixon" wrote in message
...
My amplifier has two outputs. One is switched, and used for the
speakers in the living room. The other is taken via a separate
switch box to speakers in the dining room and kitchen.

Originally, the relative sound levels in all three rooms were
reasonably matched. However, during a kitchen refit, I had to
get rid of the conventional speakers, and fitted a pair of small
KEF in-ceiling units. These have a rather lower output level. If
I deselect the dining room pair, the kitchen is well enough
matched to the living room.

As a least cost work-around, it strikes me that I might be able
to improve the situation by inserting series resistors in the
feed to the dining room. Would this work? Living in a semi, I
don't run at particularly high sound levels.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

If the dining room application is for background music during meals, then
it should work fine by attenuating the 'speakers relative to the others.
Unless you know how many dBs you need to attenuate, and can then
calculate the series resistance value, you'll be better off getting a
loudspeaker volume control as is used in Pubs and Restaurants for just
such an application. They're not expensive and it does allow you to make
changes easily.

This will do it.
http://cpc.farnell.com/_/bt936/louds...all/dp/AV01580

It's a transformer-based design (presumably a variable auto-transformer,
like a Variac). A bit more expensive than a couple of 5-10 watt
resistors, but the extra flexibility is worth-while.

S.

--
http://audiopages.googlepages.com

There is something odd about that part - a pair of audio transformers
rated 60W with 20Hz to 20kHz response in package 140mm x 85mm x 45mm - and
variable as well - and for £20. Don't expect it to sound very good.

Michael Kellett

Yes, but they are most likely auto transformers, and I wouldn't believe the
response....they don't quote dB limits or distortion. Remember it's for
background music, not listening, so it will be adequate for the job it was
designed for. If the OP needs high quality, he will be better off with a
pair of active 'speakers and a multi-room system, but that's neither cheap
nor simple.

S.
--
http://audiopages.googlepages.com

"MK" wrote in message


http://audiopages.googlepages.com

There is something odd about that part - a pair of audio
transformers rated 60W with 20Hz to 20kHz response in
package 140mm x 85mm x 45mm - and variable as well - and
for £20. Don't expect it to sound very good.

They never actually have to pass the entire 60 watts, only a fraction of it.

And, they have a reputation for not being perfectly flat over the entire
range. Face it, with typical extension speakers response down to 80 Hz would
probably suffice.

I was just thinking this. I keep thinking saturated core for some reason.
Are we sure its not just two wirewound pots as I have in an old QED device?
They tend to be noisy when you move them though.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"MK" wrote in message
...

"Serge Auckland" wrote in message
...

"Chris J Dixon" wrote in message
...
My amplifier has two outputs. One is switched, and used for the
speakers in the living room. The other is taken via a separate
switch box to speakers in the dining room and kitchen.

Originally, the relative sound levels in all three rooms were
reasonably matched. However, during a kitchen refit, I had to
get rid of the conventional speakers, and fitted a pair of small
KEF in-ceiling units. These have a rather lower output level. If
I deselect the dining room pair, the kitchen is well enough
matched to the living room.

As a least cost work-around, it strikes me that I might be able
to improve the situation by inserting series resistors in the
feed to the dining room. Would this work? Living in a semi, I
don't run at particularly high sound levels.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

If the dining room application is for background music during meals, then
it should work fine by attenuating the 'speakers relative to the others.
Unless you know how many dBs you need to attenuate, and can then
calculate the series resistance value, you'll be better off getting a
loudspeaker volume control as is used in Pubs and Restaurants for just
such an application. They're not expensive and it does allow you to make
changes easily.

This will do it.
http://cpc.farnell.com/_/bt936/louds...all/dp/AV01580

It's a transformer-based design (presumably a variable auto-transformer,
like a Variac). A bit more expensive than a couple of 5-10 watt
resistors, but the extra flexibility is worth-while.

S.

--
http://audiopages.googlepages.com

There is something odd about that part - a pair of audio transformers
rated 60W with 20Hz to 20kHz response in package 140mm x 85mm x 45mm - and
variable as well - and for £20. Don't expect it to sound very good.

Michael Kellett

"Brian Gaff" wrote in message
om...
I was just thinking this. I keep thinking saturated core for some reason.
Are we sure its not just two wirewound pots as I have in an old QED device?
They tend to be noisy when you move them though.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________
They could be, but the CPC site says they are transformer based, so I have
assumed they use a tapped autotransformer, like a Variac.

S.

"Serge Auckland" wrote in
message
"Brian Gaff" wrote in message
om...
I was just thinking this. I keep thinking saturated core
for some reason. Are we sure its not just two wirewound
pots as I have in an old QED device? They tend to be
noisy when you move them though. Brian

--
Brian Gaff....Note, this account does not accept Bcc:
email. graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________
They could be, but the CPC site says they are transformer
based, so I have assumed they use a tapped
autotransformer, like a Variac.

Right.

The transformer is designed to present twice the nominal impedance of the
speakers to the amplifer, and uses boot/buck winding configurations to
minimize the actual power the transformer needs to handle.

"Serge Auckland"

They could be, but the CPC site says they are transformer based, so I have
assumed they use a tapped autotransformer, like a Variac.


** Do NOT under any circumstances use such devices.

They are 100%, guaranteed amplifier DESTROYERS !

Attenuators used with solid state hi-fi amplifiers must not be of the
auto-transformer type.

Seen the damage using them does, many times.

Think low frequency core saturation, very low DC resistance.

Bad news !!!


...... Phil

"MK"

This will do it.
http://cpc.farnell.com/_/bt936/louds...all/dp/AV01580

It's a transformer-based design (presumably a variable auto-transformer,
like a Variac). A bit more expensive than a couple of 5-10 watt
resistors, but the extra flexibility is worth-while.

There is something odd about that part - a pair of audio transformers
rated 60W with 20Hz to 20kHz response in package 140mm x 85mm x 45mm - and
variable as well - and for £20. Don't expect it to sound very good.


** Expect it to blow your amplifier.

Here is a nice pic of the insides:

http://www.avstorm.co.uk/Switch_boxe...36_17 63.html

Consists only of a multi-position switch and 2 tiny auto-transformers.




...... Phil