On Feb 28, 6:20*pm, mikeos wrote:
On 28/02/2011 00:06, Martin Jay wrote: http://www.bbc.co.uk/news/uk-12591587:

* Can a 74-year-old microphone last spoken into by King George VI still

be used to broadcast live to the nation? Paddy O'Connell, presenter of
Radio 4's Broadcasting House, thought it might be worth a try.

The answer to the question is

No, it doesn't have a USB interface! :-)

" wrote in message
...
On Feb 28, 6:20 pm, mikeos wrote:
On 28/02/2011 00:06, Martin Jay wrote: http://www.bbc.co.uk/news/uk-12591587:

Can a 74-year-old microphone last spoken into by King George VI still

be used to broadcast live to the nation? Paddy O'Connell, presenter of
Radio 4's Broadcasting House, thought it might be worth a try.

The answer to the question is

No, it doesn't have a USB interface! :-)

When I was little, I dismantled an old carbon microphone to see how it worked
I just hope to God it wasn't the last surviving example of this.
http://www.btinternet.com/~roger.bec...h/mics/bth.htm

Only joking, but it was similar, suspended in a metal hoop on four springs.
it had a Bakelite base housing the "induction coil" transformer, I remember
being surprised that the core was made up of many parallel iron wires.

Needless to say, I wish I still had it.


--
Graham.

%Profound_observation%

Graham. wrote:

Only joking, but it was similar, suspended in a metal hoop on four springs.
it had a Bakelite base housing the "induction coil" transformer, I remember
being surprised that the core was made up of many parallel iron wires.

As a child I discovered that the carbon mike inserts used by the GPO
would get very hot if subject to a high voltage. This was during
attempts to get a usable audio link between our house and my mate's
using very thin blasting wire nicked from the quarry and a lot of
enormous batteries nicked from the railway.

Bill

"Bill Wright" wrote in message
...
Graham. wrote:

Only joking, but it was similar, suspended in a metal hoop on four
springs.
it had a Bakelite base housing the "induction coil" transformer, I
remember
being surprised that the core was made up of many parallel iron wires.

As a child I discovered that the carbon mike inserts used by the GPO would
get very hot if subject to a high voltage. This was during attempts to get
a usable audio link between our house and my mate's using very thin
blasting wire nicked from the quarry and a lot of enormous batteries
nicked from the railway.


I had a carbon hand mic in a very substatial bakelite case
and padding with a switch on the side. It had the British WD
mark and broad arrrow on the back plus RTC (Royal Tank Corps)
and 2DG (2nd Dragoon Guards) After a while, I exchanged it for a
78rpm record; "All Shook Up" which I still have. I wonder if that
spotty kid in short trousers still has my mic? I would like it back:-)


Iain

"Iain Churches" wrote in message
...

"Bill Wright" wrote in message
...
Graham. wrote:

Only joking, but it was similar, suspended in a metal hoop on four
springs.
it had a Bakelite base housing the "induction coil" transformer, I
remember
being surprised that the core was made up of many parallel iron wires.

As a child I discovered that the carbon mike inserts used by the GPO
would get very hot if subject to a high voltage. This was during attempts
to get a usable audio link between our house and my mate's using very
thin blasting wire nicked from the quarry and a lot of enormous batteries
nicked from the railway.


I had a carbon hand mic in a very substatial bakelite case
and padding with a switch on the side. It had the British WD
mark and broad arrrow on the back plus RTC (Royal Tank Corps)
and 2DG (2nd Dragoon Guards) After a while, I exchanged it for a
78rpm record; "All Shook Up" which I still have. I wonder if that
spotty kid in short trousers still has my mic? I would like it back:-)


I also had a microphone answering to more or less that description. Inside
was a standard "transmitter insert No 13", the carbon microphone used in GPO
telephones at the time. The "No 13" had an amazingly long service life,
introduced with the telephone 162 in the early 1930s it was used for all the
200 and 300 series telephones and early issues of the 700 series, finally
being replaced by the "transmitter insert No 21" in the mid 1960s. And then
the "21" was found to be far less reliable than the "13" had been. My first
job after leaving school was to test a huge batch of "21"s that he been
returned as "faulty", as part of a project to find out the cause of the
premature failure of the 21.

It was a different world back then.


David.

"David Looser" wrote in message
...
"Iain Churches" wrote in message
...

"Bill Wright" wrote in message
...
Graham. wrote:

Only joking, but it was similar, suspended in a metal hoop on four
springs.
it had a Bakelite base housing the "induction coil" transformer, I
remember
being surprised that the core was made up of many parallel iron wires.

As a child I discovered that the carbon mike inserts used by the GPO
would get very hot if subject to a high voltage. This was during
attempts to get a usable audio link between our house and my mate's
using very thin blasting wire nicked from the quarry and a lot of
enormous batteries nicked from the railway.


I had a carbon hand mic in a very substatial bakelite case
and padding with a switch on the side. It had the British WD
mark and broad arrrow on the back plus RTC (Royal Tank Corps)
and 2DG (2nd Dragoon Guards) After a while, I exchanged it for a
78rpm record; "All Shook Up" which I still have. I wonder if that
spotty kid in short trousers still has my mic? I would like it back:-)


I also had a microphone answering to more or less that description. Inside
was a standard "transmitter insert No 13", the carbon microphone used in
GPO telephones at the time. The "No 13" had an amazingly long service
life, introduced with the telephone 162 in the early 1930s it was used for
all the 200 and 300 series telephones and early issues of the 700 series,
finally being replaced by the "transmitter insert No 21" in the mid
1960s. And then the "21" was found to be far less reliable than the "13"
had been. My first job after leaving school was to test a huge batch of
"21"s that he been returned as "faulty", as part of a project to find out
the cause of the premature failure of the 21.

It was a different world back then.

:-)

Indeed. The mic looked a bit like a thick lollipop.
The top part of the body which contained the mic was
disc shaped about 7.5cm in diameter, and 3cms in depth.
The front was pierced with holes, and could be unscrewed,
and the insert removed. There was a spring loaded push
switch on the right hand side of the handle.

Did you find out why the type 21 failed?

Iain