R
Ross Herbert
- Jan 1, 1970
- 0
:
:Hello Tony and everyone, I am the OP.
:
:I've been away for a few days and I see there's so many posts that
:now I'm trying to get through them all!
:
:
:MY OBJECTIVE
:
:My aim is to take voice recordings made on various equipment and save
:them to a PC. Some of the voice recordings are of telephone
:conversations made onto tape. I would prefer to have fed the phone
:signal direct to the PC but I get a lot of noise.
:
:I want to preserve as much quality as possible because it will
robably be necessary for a third party to identify the person
:speaking.
:
:------
:
:Secondly and quite separately from the above....
:
:I didn't raise this problem in my first post. I am getting hum and
:noise when I record using a purpose build connector (Retell model 156
:~ see link below) to a hand-held battery-powered flash-memory
:recorder even when the phone is on hook. I can't see where the hum
:is coming from unless it is on the phone line because there can't be
:a ground loop this time.
:
:http://www.telephonerecorder.co.uk/recording/connectors/156.htm
:
:I do know my landlines don't have all the hum and noise so they must
:be doing something which I want for my recorder! I thought may be a
:transformer to better terminate the Virgin Media phone line might
:help but I am out of my depth here and line termination may be the
:wrong idea altogther.
:
:
EFINITIONS
:
:I guess my use of the word "matching" is not a very good electrical
:description. I'm not seeking to match impedances and I get the
:feeling that in electrical engineering, "matching" is often shorthand
:for impedence matching. So apologies for any confusion I have
:caused.
:
:I want to minimise any ground loop to reduce hum and other spuriae so
erhaps I should have said "isolating" transformer.
:
:Retell have a model (the 157) which connects direct to a PC and I
:believe it is identical to the 156 except it has the additional
:transformer I am asking about.
Get an approved line isolation unit such as this
http://www.dallasdelta.com/pdfs/liu_3kv.pdf
Since your PC is mains powered and it may not have the required isolation
between the mains side and the sound card input you can do your own thing using
an approved 600:600 transformer with 3kV isolation rating to interface the
telephone line to the sound card input.
:Hello Tony and everyone, I am the OP.
:
:I've been away for a few days and I see there's so many posts that
:now I'm trying to get through them all!
:
:
:MY OBJECTIVE
:
:My aim is to take voice recordings made on various equipment and save
:them to a PC. Some of the voice recordings are of telephone
:conversations made onto tape. I would prefer to have fed the phone
:signal direct to the PC but I get a lot of noise.
:
:I want to preserve as much quality as possible because it will
robably be necessary for a third party to identify the person
:speaking.
:
:------
:
:Secondly and quite separately from the above....
:
:I didn't raise this problem in my first post. I am getting hum and
:noise when I record using a purpose build connector (Retell model 156
:~ see link below) to a hand-held battery-powered flash-memory
:recorder even when the phone is on hook. I can't see where the hum
:is coming from unless it is on the phone line because there can't be
:a ground loop this time.
:
:http://www.telephonerecorder.co.uk/recording/connectors/156.htm
:
:I do know my landlines don't have all the hum and noise so they must
:be doing something which I want for my recorder! I thought may be a
:transformer to better terminate the Virgin Media phone line might
:help but I am out of my depth here and line termination may be the
:wrong idea altogther.
:
:
EFINITIONS
:
:I guess my use of the word "matching" is not a very good electrical
:description. I'm not seeking to match impedances and I get the
:feeling that in electrical engineering, "matching" is often shorthand
:for impedence matching. So apologies for any confusion I have
:caused.
:
:I want to minimise any ground loop to reduce hum and other spuriae so
erhaps I should have said "isolating" transformer.
:
:Retell have a model (the 157) which connects direct to a PC and I
:believe it is identical to the 156 except it has the additional
:transformer I am asking about.
Get an approved line isolation unit such as this
http://www.dallasdelta.com/pdfs/liu_3kv.pdf
Since your PC is mains powered and it may not have the required isolation
between the mains side and the sound card input you can do your own thing using
an approved 600:600 transformer with 3kV isolation rating to interface the
telephone line to the sound card input.