Hi,

I hope this is not off topic.

I see CPC (and I'm sure others) sell adaptors that convert mono plugs
to stereo ones or vice versa.

Something like this:
http://cpc.farnell.com/pro-signal/ps...-st/dp/AV17274

I realise that in addition to the stereo to mono conversion, this
particular example is also converting sizes but as far as the
electrical side of things goes, does the adaptor simply short the left
and right channels together?

Wouldn't plugging a mono plug into a stereo socket achieve exactly the
same thing without an adaptor (assuming the plug and socket were the
same size)?

I presume these adaptors are more useful when plugging a stereo plug
into a mono socket, which otherwise might only receive one channel?

TIA

In article ,
Fred wrote:
I realise that in addition to the stereo to mono conversion, this
particular example is also converting sizes but as far as the
electrical side of things goes, does the adaptor simply short the left
and right channels together?

It rather depends. Amplifier outputs are usually low impedance and may not
like being connected in parallel. So to be safe you'd use a resistor in
each leg to prevent distortion. Going the other way round - mono to
stereo, so two inputs are connected - is usually ok.

Wouldn't plugging a mono plug into a stereo socket achieve exactly the
same thing without an adaptor (assuming the plug and socket were the
same size)?

You'd be hoping the single tip mates with the twin stereo contacts. Which
it may or may not do reliably.

--
*Why do they put Braille on the drive-through bank machines?

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

On May 16, 1:45*pm, Fred wrote:
Hi,

I hope this is not off topic.

I see CPC (and I'm sure others) sell adaptors that convert mono plugs
to stereo ones or vice versa.

Something like this:http://cpc.farnell.com/pro-signal/ps...-6-35-mono-to-...

I realise that in addition to the stereo to mono conversion, this
particular example is also converting sizes but as far as the
electrical side of things goes, does the adaptor simply short the left
and right channels together?

Wouldn't plugging a mono plug into a stereo socket achieve exactly the
same thing without an adaptor (assuming the plug and socket were the
same size)?

I presume these adaptors are more useful when plugging a stereo plug
into a mono socket, which otherwise might only receive one channel?

TIA

A mono plug in a stereo socket connects to one channel and shorts out
the other.

Adaptors are liable to be direct connections, with no resistors.
Whether this is ideal depends on the details of the device feeding it


NT

On 16/05/2012 13:45, Fred wrote:
Hi,

I hope this is not off topic.

I see CPC (and I'm sure others) sell adaptors that convert mono plugs
to stereo ones or vice versa.

Something like this:
http://cpc.farnell.com/pro-signal/ps...-st/dp/AV17274

I realise that in addition to the stereo to mono conversion, this
particular example is also converting sizes but as far as the
electrical side of things goes, does the adaptor simply short the left
and right channels together?

Wouldn't plugging a mono plug into a stereo socket achieve exactly the
same thing without an adaptor (assuming the plug and socket were the
same size)?

Not quite... Mono plug in a stereo socket may well short one channel to
ground.

I presume these adaptors are more useful when plugging a stereo plug
into a mono socket, which otherwise might only receive one channel?

Indeed. There is usually enough resistance in the output drive to allow
the plug to do some crude "mixing" of the stereo channels into a single
mono one, when going the other way - but not all amps will appreciate it.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Wed, 16 May 2012 14:02:07 +0100, "Dave Plowman (News)"
wrote:


It rather depends. Amplifier outputs are usually low impedance and may not
like being connected in parallel. So to be safe you'd use a resistor in
each leg to prevent distortion. Going the other way round - mono to
stereo, so two inputs are connected - is usually ok.

I doubt these adaptors have resistors built-in, do they? It would add
complexity and cost to the design and I suppose the value of the
resistor would have to match the impedance of whatever it was
connected to, so the manufacturer would not be able to produce a "one
size fits all" item, or would they?

You'd be hoping the single tip mates with the twin stereo contacts. Which
it may or may not do reliably.

I think when I typed that a mono socket would short both channels
together I was thinking of the contacts in the socket touching the two
sections nearest the barrel end of the plug. Now that I think about
it, I think that ground is nearest the barrel, then right, then left
channel, in which case, wouldn't the right channel be shorted to
ground rather than to the left channel? Perhaps an adaptor is required
after all and I suppose for forty pence, better safe than sorry.

As it happens, I was looking for something completely different when I
stumbled across these, so it is all hypothetical but hopefully might
help somebody else.

I actually ordered a set of twin leads with phono plugs both ends to
carry left and right audio. The leads have arrived and on each plug is
printed the word "digital"! The mind boggles. Clearly a case of the
marketing department adding the word "digital" to make it sound
superior! I've gone and had a look at them and yes, they are gold
plated too

On May 18, 1:06*pm, Fred wrote:
On Wed, 16 May 2012 14:02:07 +0100, "Dave Plowman (News)"

wrote:

It rather depends. Amplifier outputs are usually low impedance and may not
like being connected in parallel. So to be safe you'd use a resistor in
each leg to prevent distortion. Going the other way round - mono to
stereo, so two inputs are connected - is usually ok.

I doubt these adaptors have resistors built-in, do they? It would add
complexity and cost to the design and I suppose the value of the
resistor would have to match the impedance of whatever it was
connected to, so the manufacturer would not be able to produce a "one
size fits all" item, or would they?

You'd be hoping the single tip mates with the twin stereo contacts. Which
it may or may not do reliably.

I think when I typed that a mono socket would short both channels
together I was thinking of the contacts in the socket touching the two
sections nearest the barrel end of the plug. Now that I think about
it, I think that ground is nearest the barrel, then right, then left
channel, in which case, wouldn't the right channel be shorted to
ground rather than to the left channel? Perhaps an adaptor is required
after all and I suppose for forty pence, better safe than sorry.

As it happens, I was looking for something completely different when I
stumbled across these, so it is all hypothetical but hopefully might
help somebody else.

I actually ordered a set of twin leads with phono plugs both ends to
carry left and right audio. The leads have arrived and on each plug is
printed the word "digital"! The mind boggles. Clearly a case of the
marketing department adding the word "digital" to make it sound
superior! I've gone and had a look at them and yes, they are gold
plated too

If you've got soldering iron, just use a stereo plug with 2 sm
resistors.


NT

In article ,
Fred wrote:
It rather depends. Amplifier outputs are usually low impedance and may
not like being connected in parallel. So to be safe you'd use a
resistor in each leg to prevent distortion. Going the other way round -
mono to stereo, so two inputs are connected - is usually ok.

I doubt these adaptors have resistors built-in, do they? It would add
complexity and cost to the design

Low power resistors cost a fraction of a penny in bulk. Probably not much
more than connecting wire.

and I suppose the value of the
resistor would have to match the impedance of whatever it was
connected to, so the manufacturer would not be able to produce a "one
size fits all" item, or would they?

This sort of socket is usually designed to drive stereo headphones of
approx 25 ohms as a maximum load. If you're using it to drive a mono amp,
the actual source impedance isn't critical. It you were using it to drive
mono headphones, they would likely be high impedance devices. So again,
not much concerned about the source impedance. If you were trying to drive
a loudspeaker, all bets are off. ;-)

--
*I love cats...they taste just like chicken.

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