jcharles00
Well-known member
I'm kind of afraid to ask this question, because it sounds pretty dumb, but after digging around here and elsewhere on the net, I've only come to a vague conclusion and I think hearing some different opinions will help make more sense of it
what functions does a microphone preamp perform?
I ask this in the context of most basic, but usable design. (say, something that will accept the XLR input of a dynamic mic and output line blanaced line level)
The obvious is that it increases the voltage of it's input signal, but it seems like impedance matching on the input and output are vital to the process as well. Conversion from differential signal to single ended too. ..and then filtering?
I know this is a nebulous question because we could get down the road of secondary features like phantom and pads, etc, etc.. but I'm talking about a simple device to get usable, "clean" audio from an SM57 into an mbox line-in without damaging anything. (as an example)
The reason I ask, is because I'm trying to wrap my head around mic pre design, and thought the best way would be to compartmentalize the device's operations to try and create very basic solutions to each part from datasheets, then compare what I came up with to existing designs. I could just wire an input jack's pin 1 and 2 to one side of an opamp with a non-inverting feedback loop and it would do _something_, but i would be ignoring issues like the impedance, and introducing more noise than necessary by not converting the balanced signal, etc.
Surely not a black and white question, but I'm not sure how else to approach this without just lifting someone else's design, and it doesn't seem like I'd get as much from that educationally.
Any input? Is this approach good/not? How would you start, designing something from scratch?
what functions does a microphone preamp perform?
I ask this in the context of most basic, but usable design. (say, something that will accept the XLR input of a dynamic mic and output line blanaced line level)
The obvious is that it increases the voltage of it's input signal, but it seems like impedance matching on the input and output are vital to the process as well. Conversion from differential signal to single ended too. ..and then filtering?
I know this is a nebulous question because we could get down the road of secondary features like phantom and pads, etc, etc.. but I'm talking about a simple device to get usable, "clean" audio from an SM57 into an mbox line-in without damaging anything. (as an example)
The reason I ask, is because I'm trying to wrap my head around mic pre design, and thought the best way would be to compartmentalize the device's operations to try and create very basic solutions to each part from datasheets, then compare what I came up with to existing designs. I could just wire an input jack's pin 1 and 2 to one side of an opamp with a non-inverting feedback loop and it would do _something_, but i would be ignoring issues like the impedance, and introducing more noise than necessary by not converting the balanced signal, etc.
Surely not a black and white question, but I'm not sure how else to approach this without just lifting someone else's design, and it doesn't seem like I'd get as much from that educationally.
Any input? Is this approach good/not? How would you start, designing something from scratch?