buzz in audio

[tg]

I bought a cheap thingy off ebay that enables me to record one side of a
telephone conversation: this thing...
http://cgi.ebay.co.uk/Telephone-Call-Recording-Phone-Adaptor-New_W0QQitemZ220321741431QQihZ012QQcategoryZ57238QQcmdZViewItemQQ_trksidZp1713.m153.l1262
Item number: 220321741431

it works ok but it causes a background buzz in the handset and it's
irritating when trying to have a phone conversation. The noise comes in
as soon as the audio jack plug touches any socket to record. Is there
any quickfix or handy gadget one can get that will eliminate this noise?
Here's a 13 second sample of it - starts with audio plug in, I pull the
plug out for a couple of seconds and then push it back in again.:
http://home.freeuk.net/tonj/buzz.mp3
thanks for any pointers.

 

[DaveM]

"tg" <tg@nospamevereverever.net> wrote in message
news:498e0b85$0$24587$da0feed9@news.zen.co.uk...

I bought a cheap thingy off ebay that enables me to record one side of a
telephone conversation: this thing...
http://cgi.ebay.co.uk/Telephone-Call-Recording-Phone-Adaptor-New_W0QQitemZ220321741431QQihZ012QQcategoryZ57238QQcmdZViewItemQQ_trksidZp1713.m153.l1262
Item number: 220321741431

it works ok but it causes a background buzz in the handset and it's
irritating when trying to have a phone conversation. The noise comes in as
soon as the audio jack plug touches any socket to record. Is there any
quickfix or handy gadget one can get that will eliminate this noise? Here's a
13 second sample of it - starts with audio plug in, I pull the plug out for a
couple of seconds and then push it back in again.:
http://home.freeuk.net/tonj/buzz.mp3
thanks for any pointers.

Typically, when you get a hum or buzz on a telephone, it's because there is a
lower than normal impedance to ground in the system. Telephones are meant to
have a balanced line, meaning that there is no "ground" connection to either of
the two wires.
Since your new device introduces the buzz into the system, we can reasonably
assume that it has a leakage to ground. This is likely to be through the
connection into the recording device, whether it be a cassette recorder, a
computer, or whatever.

You have several options.
(1) Return the device to the seller as being defective. It shouldn't cause the
buzz.
(2) Open the device and try to figure out the connections, and where the
imbalance is being introduced.
(3) Throw the device into the trash and chalk it up to bad experience.

If you choose door #2, you can get an idea of its contents by looking at
http://www.aaroncake.net/circuits/phonetap.asp or
http://www.solorb.com/elect/phone/tap/. Relate the innards of your device to
the schematics and see which one is closer. Come back with more questions when
you have more info.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.

 

[William Sommerwerck]

Is the recorder connected to the AC line? If so, that is likely the cause of
the problem. Try using a battery-operated machine.

RadioShack sells a similar device. I've used it several times, and had
absolutely no problem.

 

On Sat, 7 Feb 2009 22:33:50 -0000, "tg" <tg@nospamevereverever.net>
wrote:

I bought a cheap thingy off ebay that enables me to record one side of a
telephone conversation: this thing...
http://cgi.ebay.co.uk/Telephone-Call-Recording-Phone-Adaptor-New_W0QQitemZ220321741431QQihZ012QQcategoryZ57238QQcmdZViewItemQQ_trksidZp1713.m153.l1262
Item number: 220321741431

it works ok but it causes a background buzz in the handset and it's
irritating when trying to have a phone conversation. The noise comes in
as soon as the audio jack plug touches any socket to record. Is there
any quickfix or handy gadget one can get that will eliminate this noise?
Here's a 13 second sample of it - starts with audio plug in, I pull the
plug out for a couple of seconds and then push it back in again.:
http://home.freeuk.net/tonj/buzz.mp3
thanks for any pointers.

It could be the wires on your phone are reversed. There is a right
and wrong way to connect them. Normally a red and a green on single
line systems. Try reversing them.
I this thing is plugged into an AC outlet, and dont have a ground
prong, reverse the plug in the outlet.

LM

 

[tg]

<letterman@invalid.com> wrote in message
news:qnbso455kbi73u8no6rahgnl1jtg9u79sj@4ax.com...

On Sat, 7 Feb 2009 22:33:50 -0000, "tg" <tg@nospamevereverever.net
wrote:

It could be the wires on your phone are reversed. There is a right
and wrong way to connect them. Normally a red and a green on single
line systems. Try reversing them.
I this thing is plugged into an AC outlet, and dont have a ground
prong, reverse the plug in the outlet.

thanks I tried that, no joy. I should mention this is a cisco ip phone,
not an ordinary phone and it is powered from the mains through a 48v
adaptor, so there's no disconnecting it from mains. Even if I disconnect
the ethernet cable and switch off everything else the buzz is still
there. At this moment I don't have a battery powered recorder, only
mains powered units. I think my only solution here is to find some way
or device that was specifically made to filter out this buzz, which I
think is a standard 50Khz mains buzz. I'm sure I saw something like this
once but can't remember where...