musician w electronics project -planning stage

[JR.]

Sorry but I can't follow exactly what you are asking...

You do not need to load sources down with impedance equal to their source impedance, Bridging terminations use 10x or more the source impedance.

JR

[Phidelity]

Sorry but I can't follow exactly what you are asking...

You do not need to load sources down with impedance equal to their source impedance, Bridging terminations use 10x or more the source impedance.

JR

Sorry my post is verbose and I'm certain I haven't been using clear electronics language to illustrate my concern.

Basically I have two concerns

1) Because i am building a series resister network; if i use resistors of values <= 50 ohms there is a situation where the current is really high. 24 mA which from reading specs on my audio gear that is too high and i don't want to damage anything; If i increase the values of the resisters to >=100 ohms then i run into a situation where I the voltage drop has increased to the point that is (effectively *) beyond the resolution of the 24 bit ADC.

*I say effectively because i would be trying to identify/ distinguish 2 frets with 1 dB of voltage change. This can be discerned in a 24 bit ADC but I am expecting another phenomenon to interfere and that is a change in the conductivity of the string due to its shape changing after the string is plucked. I 'think' the effect will create a voltage change is greater than that resolution and will create a sampling error. To summerize as the string is dymnamically vibrating it's conductivity is being altered in an analogous fashion ( with a phase difference) that I suspect will be more than .5 db voltage change.

2) Because the resistance of my component has such a wide range( 100 ohms->2200 ohm) I am wondering how to best keep the voltage transfer between the three devices efficient. input signal from the synth (which has an output impedance of 100 Ohm) to my controller then from my controller to the preamp stage (with an input impedance >1200 ohm). From what i have read for best voltage transfer in an audio system impedance bridging is the best method. how do i accomplish this?

What i am trying to wrap my head around is how my resister network is going to interact with the source signal and the preamp. Because I am new to this, i think i understand the problem and to a point some solutions but ...it is all new infromation to me.

Is that a better explanation?

thanks JR for taking the time to help me out

phi

[JR.]

Sorry my post is verbose and I'm certain I haven't been using clear electronics language to illustrate my concern.

Basically I have two concerns

1) Because i am building a series resister network; if i use resistors of values <= 50 ohms there is a situation where the current is really high. 24 mA which from reading specs on my audio gear that is too high and i don't want to damage anything; If i increase the values of the resisters to >=100 ohms then i run into a situation where I the voltage drop has increased to the point that is (effectively *) beyond the resolution of the 24 bit ADC.

Voltage dividers are based on ratios. The voltage step size is independent of the resistance, but a function of the ratio between resistor values.
-------

1 dB is roughly 10%. 8 bit a/d provides 256 steps or <1/2% resolution.

*I say effectively because i would be trying to identify/ distinguish 2 frets with 1 dB of voltage change. This can be discerned in a 24 bit ADC but I am expecting another phenomenon to interfere and that is a change in the conductivity of the string due to its shape changing after the string is plucked. I 'think' the effect will create a voltage change is greater than that resolution and will create a sampling error. To summerize as the string is dymnamically vibrating it's conductivity is being altered in an analogous fashion ( with a phase difference) that I suspect will be more than .5 db voltage change.

the resistance of a metal string will not change enough to measure from being played.

2) Because the resistance of my component has such a wide range( 100 ohms->2200 ohm) I am wondering how to best keep the voltage transfer between the three devices efficient. input signal from the synth (which has an output impedance of 100 Ohm) to my controller then from my controller to the preamp stage (with an input impedance >1200 ohm). From what i have read for best voltage transfer in an audio system impedance bridging is the best method. how do i accomplish this?

connect them... 100 to 1200 is already a bridging termination (10x).

What i am trying to wrap my head around is how my resister network is going to interact with the source signal and the preamp. Because I am new to this, i think i understand the problem and to a point some solutions but ...it is all new infromation to me.

Is that a better explanation?

thanks JR for taking the time to help me out

phi

Still unclear... Are you applying a DC voltage to your resistor string to determine fretting, or some other voltage?

JR