Headset boost

[Daniel Inston]

I've attacked an old cordless phone and wired in a headset so that I can use
it hands free. I simply disconnected the phones mic and speaker and wored
them up to a headset socket.
While the mic works well; other party can hear me, I find that the earpiece
of the headset, even with the volume up loud is not quite enough if there is
any background noise.
So what I want to do is boost the phones speaker volume slightly so that the
volume control on the headset has some range to it. I thought that a garden
variety transistor might do it, along with a resistor or two.
Problem is - I dont know how - I can only follow instructions when it comes
to this sort of thing - so I am hoping that someone here will provide some
help.

Thanks in advance.
Daniel Inston

 

[Lord Garth]

"Daniel Inston" <daniel@dnisoft.com> wrote in message
news:3fbaf6c2$0$1736$5a62ac22@freenews.iinet.net.au...

I've attacked an old cordless phone and wired in a headset so that I can
use
it hands free. I simply disconnected the phones mic and speaker and wored
them up to a headset socket.
While the mic works well; other party can hear me, I find that the
earpiece
of the headset, even with the volume up loud is not quite enough if there
is
any background noise.
So what I want to do is boost the phones speaker volume slightly so that
the
volume control on the headset has some range to it. I thought that a
garden
variety transistor might do it, along with a resistor or two.
Problem is - I dont know how - I can only follow instructions when it
comes
to this sort of thing - so I am hoping that someone here will provide some
help.

Was it driving a moving coil speaker or a crystal type speaker originally?
Is it a similar type to the headphones? I'm guessing that the impedance is
mismatched greatly with the headphone.

 

[Daniel Inston]

"Lord Garth" <LGarth@Tantalus.net> wrote in message
news:hlKub.1190$I32.630@newssvr23.news.prodigy.com...

"Daniel Inston" <daniel@dnisoft.com> wrote in message
news:3fbaf6c2$0$1736$5a62ac22@freenews.iinet.net.au...
I've attacked an old cordless phone and wired in a headset so that I can
use
it hands free. I simply disconnected the phones mic and speaker and
wored
them up to a headset socket.
While the mic works well; other party can hear me, I find that the
earpiece
of the headset, even with the volume up loud is not quite enough if
there
is
any background noise.
So what I want to do is boost the phones speaker volume slightly so that
the
volume control on the headset has some range to it. I thought that a
garden
variety transistor might do it, along with a resistor or two.
Problem is - I dont know how - I can only follow instructions when it
comes
to this sort of thing - so I am hoping that someone here will provide
some
help.

Was it driving a moving coil speaker or a crystal type speaker originally?
Is it a similar type to the headphones? I'm guessing that the impedance
is
mismatched greatly with the headphone.



Actually, the impedance is the same - or at least within 1 or 2 ohms - they

are both about 33-35 ohms.
Speaker in phone is very small - so I would say that it is not a moving
coil - however I am not sure how to tell.
I really only want to boost the output a little - maybe double it - so that
the volume control has some adjustment. At the moment it is just a little
too quiet when turned up full.

Thanks
Daniel

 

[Lord Garth]

"Daniel Inston" <daniel@dnisoft.com> wrote in message
news:3fbc1033$0$1748$5a62ac22@freenews.iinet.net.au...

"Lord Garth" <LGarth@Tantalus.net> wrote in message
news:hlKub.1190$I32.630@newssvr23.news.prodigy.com...

"Daniel Inston" <daniel@dnisoft.com> wrote in message
news:3fbaf6c2$0$1736$5a62ac22@freenews.iinet.net.au...
I've attacked an old cordless phone and wired in a headset so that I
can
use
it hands free. I simply disconnected the phones mic and speaker and
wored
them up to a headset socket.
While the mic works well; other party can hear me, I find that the
earpiece
of the headset, even with the volume up loud is not quite enough if
there
is
any background noise.
So what I want to do is boost the phones speaker volume slightly so
that
the
volume control on the headset has some range to it. I thought that a
garden
variety transistor might do it, along with a resistor or two.
Problem is - I dont know how - I can only follow instructions when it
comes
to this sort of thing - so I am hoping that someone here will provide
some
help.

Was it driving a moving coil speaker or a crystal type speaker
originally?
Is it a similar type to the headphones? I'm guessing that the impedance
is
mismatched greatly with the headphone.



Actually, the impedance is the same - or at least within 1 or 2 ohms -
they
are both about 33-35 ohms.
Speaker in phone is very small - so I would say that it is not a moving
coil - however I am not sure how to tell.
I really only want to boost the output a little - maybe double it - so
that
the volume control has some adjustment. At the moment it is just a little
too quiet when turned up full.

Thanks
Daniel

If you have some power available, use an LM386...it's easy and cheap.