Thunderchild
New Member
So I want to use the non invasive method of a coil attatched as close as possible to the earpeice of a house phone so that I can record or put on speaker what is being said on the other end. what sort of amplification will I need and what type of coil for example roughly how many windings of what size wire ?
or if a direct connection to the earpeice is a better solution what should I do I don't fancy putting 40 volts into and op amp that will only take 20 for example. If I remember correctly there are dc 40 V when the line is inactive that go to 8 volts when it is active so would a blocking condenser be sufficient ?
hm better go route out some op amps
or if a direct connection to the earpeice is a better solution what should I do I don't fancy putting 40 volts into and op amp that will only take 20 for example. If I remember correctly there are dc 40 V when the line is inactive that go to 8 volts when it is active so would a blocking condenser be sufficient ?
hm better go route out some op amps