sea mouse
Member
Hi all
I racked a few v672 modules as mic pre-amps a while back and never got around to labelling the input impedance settings. I used a dual 4-position switch, having followed the threads in this forum, and set RE resistor values at 40, 600, 1200, and 2400 Ω. There is one RE resistor on each hot and cold connection, as in the datasheet guidance. My intention was to have the input impedances switchable between 40, 600, 1200, and 2400Ω.
However, I am all of a sudden unsure about how the input impedance relates to a pair of RE resistors (one on hot and one on cold). Does an RE value of 40Ω set an impedance of 40Ω or does it result in 80Ω input impedance?
I thought I understood it, but somehow I don't. I know impedance is frequency dependent but does the input impedance relate to the resistance between hot and cold, or the resistance between hot and ground, and cold and ground, or is it determined after a balanced signal has become unbalanced?
It seems to me that according to the datasheet using RE resistors at 40Ω on hot and 40Ω on cold should result in an input impedance of 40Ω.
Is that correct?
Sean
I racked a few v672 modules as mic pre-amps a while back and never got around to labelling the input impedance settings. I used a dual 4-position switch, having followed the threads in this forum, and set RE resistor values at 40, 600, 1200, and 2400 Ω. There is one RE resistor on each hot and cold connection, as in the datasheet guidance. My intention was to have the input impedances switchable between 40, 600, 1200, and 2400Ω.
However, I am all of a sudden unsure about how the input impedance relates to a pair of RE resistors (one on hot and one on cold). Does an RE value of 40Ω set an impedance of 40Ω or does it result in 80Ω input impedance?
I thought I understood it, but somehow I don't. I know impedance is frequency dependent but does the input impedance relate to the resistance between hot and cold, or the resistance between hot and ground, and cold and ground, or is it determined after a balanced signal has become unbalanced?
It seems to me that according to the datasheet using RE resistors at 40Ω on hot and 40Ω on cold should result in an input impedance of 40Ω.
Is that correct?
Sean
