pyjaman
Well-known member
Hello, gentlemen.
Here the deal:
a friend of mine who works as a PA system engineer asked me to imagine and build a gizmo for him that could take audio signal at the output of a 4KW PA amp, attenuate and convert it into a balanced line level for FFT analisys purpose. Don't ask me why. ultra low noise is not a problem for PA use, but very flat frequency response, and very low disortion are important for his purpose.
He needs it for the very next days, so we're in a hurry.
It has to be simple also, because I don't have time to build and test something complicated, and despite my learning efforts, my knowledge is somewhat limited (I'm an average live tech and DIYer, not an electronic engineer).
I was thinking of a 1/200 resistive divider (as the amp can output about 300V max) in parallele to the load, made of High value resistors (to avoid any loading disturbance to the amp/speaker), followed by a good FET ultra low distortion opamp, (with offset trim?) , directly coupled to a THAT balanced line driver.
Normally, no DC is present at the amp output.
Maybe there are problems I'm not aware of, or maybe it could be much simpler, that's why I'm begging for your help. Idealy, it would be smarter if powered by the console phantome, but discrete design is far beyond my knowledge.
I'm aware that's not one of the most exciting topic of the year, but my friend is a great guy, and I owe him a lot, that's why I'd really like to be able to do it for him.
But I won't be able to do it in such a short time without any help.
So, any inputs from the good souls here?
Thanks,
Laurent.
Here the deal:
a friend of mine who works as a PA system engineer asked me to imagine and build a gizmo for him that could take audio signal at the output of a 4KW PA amp, attenuate and convert it into a balanced line level for FFT analisys purpose. Don't ask me why. ultra low noise is not a problem for PA use, but very flat frequency response, and very low disortion are important for his purpose.
He needs it for the very next days, so we're in a hurry.
It has to be simple also, because I don't have time to build and test something complicated, and despite my learning efforts, my knowledge is somewhat limited (I'm an average live tech and DIYer, not an electronic engineer).
I was thinking of a 1/200 resistive divider (as the amp can output about 300V max) in parallele to the load, made of High value resistors (to avoid any loading disturbance to the amp/speaker), followed by a good FET ultra low distortion opamp, (with offset trim?) , directly coupled to a THAT balanced line driver.
Normally, no DC is present at the amp output.
Maybe there are problems I'm not aware of, or maybe it could be much simpler, that's why I'm begging for your help. Idealy, it would be smarter if powered by the console phantome, but discrete design is far beyond my knowledge.
I'm aware that's not one of the most exciting topic of the year, but my friend is a great guy, and I owe him a lot, that's why I'd really like to be able to do it for him.
But I won't be able to do it in such a short time without any help.
So, any inputs from the good souls here?
Thanks,
Laurent.