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Does it cause interference?

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Electronman

New Member
Hi,

Just want to know if it is possible to use a stereo amplifier like TDA1557Q so that it does amplify 2 spread signals?
I have a MP3 player and a mike with preamplifier on it; now want to know if I am able to connect these both devices to each channels of the amplifier without any problem or interference? Or the amplifier will cause them to interference each other?
If they interference each others whats the solution?

Thanks in advance.
 

MikeMl

Well-Known Member
Most Helpful Member
Are you asking about using two channels of a stereo amp to amplify totally unrelated signals; voice in one channel and music in the other? If so, there will be a spec on the data sheet that expresses "isolation" or "channel separation" or something like that. This is a measure of how much the signal in one channel couples into the other, usually expressed in db. For unrelated signals, you probably need more than 60db of isolation...
 

Electronman

New Member
Are you asking about using two channels of a stereo amp to amplify totally unrelated signals; voice in one channel and music in the other? If so, there will be a spec on the data sheet that expresses "isolation" or "channel separation" or something like that. This is a measure of how much the signal in one channel couples into the other, usually expressed in db. For unrelated signals, you probably need more than 60db of isolation...
Yea thats exactly what I want to do.
The datasheet tels that channel separation is 40dB for TDA1557Q so It can not be used as what I want, right?

I am wondering why both channels in a stereo amplifier are not completely separated of each other? Is not it bad for a stereo amplifier to work while both channels are affecting each others?
 
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Nigel Goodwin

Super Moderator
Most Helpful Member
Yea thats exactly what I want to do.
It is 40dB for TDA1557Q so It can not be used as what I want right?

I am wondering why both channels in a stereo amplifier are not completely separated of each other? It is not bad for a stereo amplifier to work while both channels are affecting each others?
Then don't use a stereo IC, use two mono amplifiers - use the right solution for the problem, don't complain that choosing the totally wrong solution doesn't do what you want.
 

audioguru

Well-Known Member
Most Helpful Member
The TDA1557Q stereo bridged amplifier has 13 pins. Since you need two mono bridged amplifiers then use two TDA7240A amplifiers instead that each has only 7 pins.
 

Electronman

New Member
I think I told my goal?!
Anyway I found that it is not possible to do so. besides I learnt a new phrase for stereo amplifiers.
Thanks to you Nigel and to you Mike.
 
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